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Imaging Atherosclerosis and Risk of Plaque Rupture  

PubMed Central

Atherosclerosis imaging strategies can delineate characteristics of plaques at risk of rupture and thrombosis. Structural plaque imaging identifies high-risk plaque features including lipid pools, thin fibrous caps, and intraplaque hemorrhage, among others. New molecular imaging techniques complement structural imaging approaches by illuminating important features of plaque biology, with a prominent focus on detecting inflammation as a high-risk phenotype. As we unravel the molecular and structural characteristics underlying thrombosis-prone plaques, there is significant promise for eventual early identification and prediction of atherosclerotic plaque complications before they occur. Here we focus on recent imaging insights into high-risk arterial plaques, the etiologic agent of acute myocardial infarction (MI), stroke, and sudden cardiac death. PMID:23982263

Osborn, Eric A; Jaffer, Farouc A



Atherosclerotic plaque rupture and thrombosis. Evolving concepts.  


Rupture of an atherosclerotic plaque associated with partial or complete thrombotic vessel occlusion is fundamental to the development of ischemic coronary syndromes. Plaques that produce only mild-to-moderate angiographic luminal stenosis are frequently those that undergo abrupt disruption, leading to unstable angina or acute myocardial infarction. Plaques with increased lipid content appear more prone to rupture, particularly when the lipid pool is localized eccentrically within the intima. Macrophages appear to play an important role in atherogenesis, perhaps by participating in the uptake and metabolism of lipoproteins, secretion of growth factors, and production of enzymes and toxic metabolites that may facilitate plaque rupture. In addition, the particular composition or configuration of a plaque and the hemodynamic forces to which it is exposed may determine its susceptibility to disruption. Exposure of collagen, lipids, and smooth muscle cells after plaque rupture leads to the activation of platelets and the coagulation cascade system. The resulting thrombus may lead to marked reduction in myocardial perfusion and the development of an unstable coronary syndrome, or it may become organized and incorporated into the diseased vessel, thus contributing to the progression of atherosclerosis. In unstable angina, plaque disruption leads to thrombosis, which is usually labile and results in only a transient reduction in myocardial perfusion. Release of vasoactive substances, arterial spasm, or increases in myocardial oxygen demand may contribute to ischemia. In acute myocardial infarction, plaque disruption results in a more persistent thrombotic vessel occlusion; the extent of necrosis depends on the size of the artery, the duration of occlusion, the presence of collateral flow, and the integrity of the fibrinolytic system. Thrombi that undergo lysis expose a highly thrombogenic surface to the circulating blood, which has the capacity of activating platelets and the coagulation cascade system and may lead to thrombotic reocclusion. Measurements aimed at reversing the process of atherosclerosis via cholesterol reduction and enhanced high density lipoprotein activity are encouraging. Active research is being focused on the development of new antithrombotic tools, such as inhibitors of thrombin, thromboxane, and serotonin receptor antagonists, and monoclonal antibodies aimed at blocking platelet membrane receptors or adhesive proteins. These compounds may prove useful when immediate and potent inhibition of the hemostatic system is desired. Intensive research is still needed in the areas of pathogenesis and therapeutic intervention in atherosclerosis. PMID:2203564

Fuster, V; Stein, B; Ambrose, J A; Badimon, L; Badimon, J J; Chesebro, J H



Thrombosis formation on atherosclerotic lesions and plaque rupture.  


Atherosclerosis is a silent chronic vascular pathology that is the cause of the majority of cardiovascular ischaemic events. The evolution of vascular disease involves a combination of endothelial dysfunction, extensive lipid deposition in the intima, exacerbated innate and adaptive immune responses, proliferation of vascular smooth muscle cells and remodelling of the extracellular matrix, resulting in the formation of an atherosclerotic plaque. High-risk plaques have a large acellular lipid-rich necrotic core with an overlying thin fibrous cap infiltrated by inflammatory cells and diffuse calcification. The formation of new fragile and leaky vessels that invade the expanding intima contributes to enlarge the necrotic core increasing the vulnerability of the plaque. In addition, biomechanical, haemodynamic and physical factors contribute to plaque destabilization. Upon erosion or rupture, these high-risk lipid-rich vulnerable plaques expose vascular structures or necrotic core components to the circulation, which causes the activation of tissue factor and the subsequent formation of a fibrin monolayer (coagulation cascade) and, concomitantly, the recruitment of circulating platelets and inflammatory cells. The interaction between exposed atherosclerotic plaque components, platelet receptors and coagulation factors eventually leads to platelet activation, aggregation and the subsequent formation of a superimposed thrombus (i.e. atherothrombosis) which may compromise the arterial lumen leading to the presentation of acute ischaemic syndromes. In this review, we will describe the progression of the atherosclerotic lesion along with the main morphological characteristics that predispose to plaque rupture, and discuss the multifaceted mechanisms that drive platelet activation and subsequent thrombus formation. Finally, we will consider the current scientific challenges and future research directions. PMID:25156650

Badimon, L; Vilahur, G



Plaque Rupture Complications in Murine Atherosclerotic Vein Grafts Can Be Prevented by TIMP-1 Overexpression  

PubMed Central

The current study describes the incidence and phenotype of plaque rupture complications in murine vein grafts. Since matrix metalloproteinases (MMPs) are highly involved in atherosclerotic plaque vulnerability and plaque rupture, we hypothesized that this model can be validated by overexpression of the MMP inhibitor TIMP-1. First we studied 47 vein grafts in hypercholesterolemic ApoE3*Leiden mice for the incidence of plaque complications. In 79% of these grafts, extensive lesions with plaque rupture complications like dissections, intraplaque hemorrhages or erosions with intramural thrombi were found. Next, in vivo Near-InfraRed-Fluorescence imaging demonstrated that electroporation mediated TIMP-1-overexpression reduced local MMP activity in vein grafts by 73% (p<0.01). This led to a 40% reduction in lesion-size after 28d (p?=?0.01) and a more stable lesion phenotype with significant more smooth muscle cells (135%), collagen (47%) and significant less macrophages (44%) and fibrin (55%) than controls. More importantly, lesions in the TIMP-1 group showed a 90% reduction of plaque complications (10/18 of control mice showed plaque complications versus 1/18 in TIMP-1 treated mice). Murine vein grafts are a relevant spontaneous model to study plaque stability and subsequent hemorrhagic complications, resulting in plaque instability. Moreover, inhibition of MMPs by TIMP-1-overexpression resulted in decreased plaque progression, increased stabilization and decreased plaque rupture complications in murine vein grafts. PMID:23071737

de Vries, Margreet R.; Niessen, Hans W. M.; Lowik, Clemens W. G. M.; Hamming, Jaap F.; Jukema, J. Wouter; Quax, Paul H. A.



Biomechanics and Inflammation in Atherosclerotic Plaque Erosion and Plaque Rupture: Implications for Cardiovascular Events in Women  

PubMed Central

Objective Although plaque erosion causes approximately 40% of all coronary thrombi and disproportionally affects women more than men, its mechanism is not well understood. The role of tissue mechanics in plaque rupture and regulation of mechanosensitive inflammatory proteins is well established, but their role in plaque erosion is unknown. Given obvious differences in morphology between plaque erosion and rupture, we hypothesized that inflammation in general as well as the association between local mechanical strain and inflammation known to exist in plaque rupture may not occur in plaque erosion. Therefore, our objective was to determine if similar mechanisms underlie plaque rupture and plaque erosion. Methods and Results We studied a total of 74 human coronary plaque specimens obtained at autopsy. Using lesion-specific computer modeling of solid mechanics, we calculated the stress and strain distribution for each plaque and determined if there were any relationships with markers of inflammation. Consistent with previous studies, inflammatory markers were positively associated with increasing strain in specimens with rupture and thin-cap fibroatheromas. Conversely, overall staining for inflammatory markers and apoptosis were significantly lower in erosion, and there was no relationship with mechanical strain. Samples with plaque erosion most closely resembled those with the stable phenotype of thick-cap fibroatheromas. Conclusions In contrast to classic plaque rupture, plaque erosion was not associated with markers of inflammation and mechanical strain. These data suggest that plaque erosion is a distinct pathophysiological process with a different etiology and therefore raises the possibility that a different therapeutic approach may be required to prevent plaque erosion. PMID:25365517

Campbell, Ian C.; Suever, Jonathan D.; Timmins, Lucas H.; Veneziani, Alessandro; Vito, Raymond P.; Virmani, Renu; Oshinski, John N.; Taylor, W. Robert



Plaque rupture with severe pre-existing stenosis precipitating coronary thrombosis. Characteristics of coronary atherosclerotic plaques underlying fatal occlusive thrombi  

Microsoft Academic Search

Ruptured atheromatous plaques were identified by step-sectioning technique as responsible for 40 of 51 recent coronary artery thrombi and 63 larger intimal haemorrhages. The degree of pre-existing luminal narrowing at the site of rupture was decisive for whether plaque rupture caused occlusive thrombosis or just intimal haemorrhage. If the pre-existing stenosis was greater than 90% (histologically determined) then plaque rupture

E Falk



Macrophage Activation in Atherosclerosis: Pathogenesis and Pharmacology of Plaque Rupture  

Microsoft Academic Search

Atherosclerosis is still an important disease. It accounts for 39% of deaths in the U.K. and 12 million U.S citizens have atherosclerosis-associated disease. Atherosclerosis may exert clinical effects by slow narrowing, producing stable angina or dramatic rupture, producing acute coronary syndromes such as unstable angina or myocardial infarction and death. Macrophages are abundant in ruptured atherosclerotic plaques. Macrophages are innate

J. J. Boyle



Changing views of the biomechanics of vulnerable plaque rupture: a review.  


This review examines changing perspectives on the biomechanics of vulnerable plaque rupture over the past 25 years from the first finite element analyses (FEA) showing that the presence of a lipid pool significantly increases the local tissue stress in the atheroma cap to the latest imaging and 3D FEA studies revealing numerous microcalcifications in the cap proper and a new paradigm for cap rupture. The first part of the review summarizes studies describing the role of the fibrous cap thickness, tissue properties, and lesion geometry as main determinants of the risk of rupture. Advantages and limitations of current imaging technologies for assessment of vulnerable plaques are also discussed. However, the basic paradoxes as to why ruptures frequently did not coincide with location of PCS and why caps >65 ?m thickness could rupture at tissue stresses significantly below the 300 kPa critical threshold still remained unresolved. The second part of the review describes recent studies in the role of microcalcifications, their origin, shape, and clustering in explaining these unresolved issues including the actual mechanism of rupture due to the explosive growth of tiny voids (cavitation) in local regions of high stress concentration between closely spaced microinclusions oriented along their tensile axis. PMID:23842694

Cardoso, Luis; Weinbaum, Sheldon



Optical measurement of arterial mechanical properties: from atherosclerotic plaque initiation to rupture  

NASA Astrophysics Data System (ADS)

During the pathogenesis of coronary atherosclerosis, from lesion initiation to rupture, arterial mechanical properties are altered by a number of cellular, molecular, and hemodynamic processes. There is growing recognition that mechanical factors may actively drive vascular cell signaling and regulate atherosclerosis disease progression. In advanced plaques, the mechanical properties of the atheroma influence stress distributions in the fibrous cap and mediate plaque rupture resulting in acute coronary events. This review paper explores current optical technologies that provide information on the mechanical properties of arterial tissue to advance our understanding of the mechanical factors involved in atherosclerosis development leading to plaque rupture. The optical approaches discussed include optical microrheology and traction force microscopy that probe the mechanical behavior of single cell and extracellular matrix components, and intravascular imaging modalities including laser speckle rheology, optical coherence elastography, and polarization-sensitive optical coherence tomography to measure the mechanical properties of advanced coronary lesions. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in elucidating the mechanical aspects of coronary atherosclerosis in the future.

Nadkarni, Seemantini K.



Optical measurement of arterial mechanical properties: from atherosclerotic plaque initiation to rupture.  


During the pathogenesis of coronary atherosclerosis, from lesion initiation to rupture, arterial mechanical properties are altered by a number of cellular, molecular, and hemodynamic processes. There is growing recognition that mechanical factors may actively drive vascular cell signaling and regulate atherosclerosis disease progression. In advanced plaques, the mechanical properties of the atheroma influence stress distributions in the fibrous cap and mediate plaque rupture resulting in acute coronary events. This review paper explores current optical technologies that provide information on the mechanical properties of arterial tissue to advance our understanding of the mechanical factors involved in atherosclerosis development leading to plaque rupture. The optical approaches discussed include optical microrheology and traction force microscopy that probe the mechanical behavior of single cell and extracellular matrix components, and intravascular imaging modalities including laser speckle rheology, optical coherence elastography, and polarization-sensitive optical coherence tomography to measure the mechanical properties of advanced coronary lesions. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in elucidating the mechanical aspects of coronary atherosclerosis in the future. PMID:24296995

Nadkarni, Seemantini K



Association of statin therapy with reduced coronary plaque rupture: an optical coherence tomography study  

PubMed Central

Objective Statin therapy induces plaque regression and may stabilize atheromatous plaques. Optical coherence tomography (OCT) is a high-resolution in-vivo imaging modality that allows characterization of atherosclerotic plaques. We aimed to demonstrate the potential utility of OCT in evaluating coronary plaques in patients with or without statin therapy. Methods Patients undergoing cardiac catheterization were enrolled. We identified culprit lesions and performed intracoronary OCT imaging. Plaque lipid pool, fibrous cap thickness, and frequency of thin-cap fibroatheroma were evaluated using previously validated criteria. Macrophage density was determined from optical signals within fibrous caps. Presence of calcification, thrombosis, and rupture was assessed. Results Forty-eight patients were included (26 on statins, 22 without statins). Baseline characteristics were similar apart from lipid profile. Patients on statin therapy had lower total and low-density lipoprotein cholesterol concentrations (4.45± 1.35 vs. 5.26 ± 0.83 mmol/l, P = 0.02; 2.23 ± 0.78 vs. 3.26 ±0.62 mmol/l, P < 0.001, respectively). Frequencies of lipid-rich plaque (69 vs. 82%), thin-cap fibroatheroma (31 vs. 50%), plaque calcification (15 vs. 5%) and thrombosis (15 vs. 32%), and fibrous cap macrophage density were comparable between statin and nonstatin groups (5.9 vs. 6.3%; all P =NS). Ruptured plaques were, however, significantly less frequent in patients on established statin therapy (8 vs. 36%; P = 0.03) with a trend toward increased minimum fibrous cap thickness (78 vs. 49 ?m; P = 0.07). Conclusion We demonstrated the use of OCT in plaque characterization and found that patients on prior statin therapy have reduced incidence of ruptured plaques and a trend toward thicker fibrous caps. This suggests that statins may stabilize coronary plaques. PMID:18480667

Chia, Stanley; Raffel, Owen Christopher; Takano, Masamichi; Tearney, Guillermo J.; Bouma, Brett E.; Jang, Ik-Kyung



The Fat-Fed Apolipoprotein E Knockout Mouse Brachiocephalic Artery in the Study of Atherosclerotic Plaque Rupture  

PubMed Central

Atherosclerosis has been studied in animals for almost a century, yet the events leading up to the rupture of an atherosclerotic plaque (the underlying cause of the majority of fatal thrombosis formation) have only been studied in the past decade, due in part to the development of a mouse model of spontaneous plaque rupture. Apolipoprotein E knockout mice, when fed a high-fat diet, consistently develop lesions in the brachiocephalic artery that rupture at a known time point. It is therefore now possible to observe the development of lesions to elucidate the mechanisms behind the rupture of plaques. Critics argue that the model does not replicate the appearance of human atherosclerotic plaque ruptures. The purpose of this review is to highlight the reasons why we should be looking to the apolipoprotein E knockout mouse to further our understanding of plaque rupture. PMID:21076539

Bond, Andrew R.; Jackson, Christopher L.



Atherosclerosis and Atheroma Plaque Rupture: Imaging Modalities in the Visualization of Vasa Vasorum and Atherosclerotic Plaques  

PubMed Central

Invasive angiography has been widely accepted as the gold standard to diagnose cardiovascular pathologies. Despite its superior resolution of demonstrating atherosclerotic plaque in terms of degree of lumen stenosis, the morphological assessment for the plaque is insufficient for the analysis of plaque components, and therefore, unable to predict the risk status or vulnerability of atherosclerotic plaque. There is an increased body of evidence to show that the vasa vasorum play an important role in the initiation, progression, and complications of atherosclerotic plaque leading to major adverse cardiac events. This paper provides an overview of the evidence-based reviews of various imaging modalities with regard to their potential value for comprehensive characterization of the composition, burden, and neovascularization of atherosclerotic plaque. PMID:24688380



Biomechanical modeling and morphology analysis indicates plaque rupture due to mechanical failure unlikely in atherosclerosis-prone mice.  


Spontaneous plaque rupture in mouse models of atherosclerosis is controversial, although numerous studies have discussed so-called "vulnerable plaque" phenotypes in mice. We compared the morphology and biomechanics of two acute and one chronic murine model of atherosclerosis to human coronaries of the thin-cap fibroatheroma (TCFA) phenotype. Our acute models were apolipoprotein E-deficient (ApoE(-/-)) and LDL receptor-deficient (LDLr(-/-)) mice, both fed a high-fat diet for 8 wk with simultaneous infusion of angiotensin II (ANG II), and our chronic mouse model was the apolipoprotein E-deficient strain fed a regular chow diet for 1 yr. We found that the mouse plaques from all three models exhibited significant morphological differences from human TCFA plaques, including the plaque burden, plaque thickness, eccentricity, and amount of the vessel wall covered by lesion as well as significant differences in the relative composition of plaques. These morphological differences suggested that the distribution of solid mechanical stresses in the walls may differ as well. Using a finite-element analysis computational solid mechanics model, we computed the relative distribution of stresses in the walls of murine and human plaques and found that although human TCFA plaques have the highest stresses in the thin fibrous cap, murine lesions do not have such stress distributions. Instead, local maxima of stresses were on the media and adventitia, away from the plaque. Our results suggest that if plaque rupture is possible in mice, it may be driven by a different mechanism than mechanics. PMID:23203971

Campbell, Ian C; Weiss, Daiana; Suever, Jonathan D; Virmani, Renu; Veneziani, Alessandro; Vito, Raymond P; Oshinski, John N; Taylor, W Robert



3D Critical Plaque Wall Stress Is a Better Predictor of Carotid Plaque Rupture Sites Than Flow Shear Stress: An In Vivo MRI-Based 3D FSI Study  

PubMed Central

Atherosclerotic plaque rupture leading to stroke is the major cause of long-term disability as well as the third most common cause of mortality. Image-based computational models have been introduced seeking critical mechanical indicators, which may be used for plaque vulnerability assessment. This study extends the previous 2D critical stress concept to 3D by using in vivo magnetic resonance image (MRI) data of human atherosclerotic carotid plaques and 3D fluid-structure interaction (FSI) models to: identify 3D critical plaque wall stress (CPWS) and critical flow shear stress (CFSS) and to investigate their associations with plaque rupture. In vivo MRI data of carotid plaques from 18 patients scheduled for endarterectomy were acquired using histologically validated multicontrast protocols. Of the 18 plaques, histology-confirmed that six had prior rupture (group 1) as evidenced by presence of ulceration. The remaining 12 plaques (group 2) contained no rupture. The 3D multicomponent FSI models were constructed for each plaque to obtain 3D plaque wall stress (PWS) and flow shear stress (FSS) distributions. Three-dimensional CPWS and CFSS, defined as maxima of PWS and FSS from all vulnerable sites, were determined for each plaque to investigate their association with plaque rupture. Slice-based critical PWS and FSS were also calculated for all slices for more detailed analysis and comparison. The mean 3D CPWS of group 1 was 263.44 kPa, which was 100% higher than that from group 2 (132.77, p = 0.03984). Five of the six ruptured plaques had 3D CPWS sites, matching the histology-confirmed rupture sites with an 83% agreement. Although the mean 3D CFSS (92.94 dyn/cm2) for group 1 was 76% higher than that for group 2 (52.70 dyn / cm2), slice-based CFSS showed no significant difference between the two groups. Only two of the six ruptured plaques had 3D CFSS sites matching the histology-confirmed rupture sites with a 33% agreement. CFSS had a good correlation with plaque stenosis severity (R2 = 0.40 with an exponential function fitting 3D CFSS data). This in vivo MRI pilot study using plaques with and without rupture demonstrates that 3D critical plaque wall stress values are more closely associated with atherosclerotic plaque rupture then critical flow shear stresses. Critical wall stress values may become indicators of high risk sites of rupture. Future work with a larger population will establish a possible CPWS-based plaque vulnerability classification. PMID:20459195

Teng, Zhongzhao; Canton, Gador; Yuan, Chun; Ferguson, Marina; Yang, Chun; Huang, Xueying; Zheng, Jie; Woodard, Pamela K.



Stabilizing Role of Platelet P2Y12 Receptors in Shear-Dependent Thrombus Formation on Ruptured Plaques  

PubMed Central

Background In most models of experimental thrombosis, healthy blood vessels are damaged. This results in the formation of a platelet thrombus that is stabilized by ADP signaling via P2Y12 receptors. However, such models do not predict involvement of P2Y12 in the clinically relevant situation of thrombosis upon rupture of atherosclerotic plaques. We investigated the role of P2Y12 in thrombus formation on (collagen-containing) atherosclerotic plaques in vitro and in vivo, by using a novel mouse model of atherothrombosis. Methodology Plaques in the carotid arteries from Apoe?/? mice were acutely ruptured by ultrasound treatment, and the thrombotic process was monitored via intravital fluorescence microscopy. Thrombus formation in vitro was assessed in mouse and human blood perfused over collagen or plaque material under variable conditions of shear rate and coagulation. Effects of two reversible P2Y12 blockers, ticagrelor (AZD6140) and cangrelor (AR-C69931MX), were investigated. Principal Findings Acute plaque rupture by ultrasound treatment provoked rapid formation of non-occlusive thrombi, which were smaller in size and unstable in the presence of P2Y12 blockers. In vitro, when mouse or human blood was perfused over collagen or atherosclerotic plaque material, blockage or deficiency of P2Y12 reduced the thrombi and increased embolization events. These P2Y12 effects were present at shear rates >500 s?1, and they persisted in the presence of coagulation. P2Y12-dependent thrombus stabilization was accompanied by increased fibrin(ogen) binding. Conclusions/Significance Platelet P2Y12 receptors play a crucial role in the stabilization of thrombi formed on atherosclerotic plaques. This P2Y12 function is restricted to high shear flow conditions, and is preserved in the presence of coagulation. PMID:20405028

Nergiz-Unal, Reyhan; Cosemans, Judith M. E. M.; Feijge, Marion A. H.; van der Meijden, Paola E. J.; Storey, Robert F.; van Giezen, J. J. J.; oude Egbrink, Mirjam G. A.; Heemskerk, Johan W. M.; Kuijpers, Marijke J. E.



Mast cell infiltration in acute coronary syndromes: implications for plaque rupture  

Microsoft Academic Search

Objectives. To define the role of mast cells in plaque destabilization.Background. Inflammation is an essential feature of human coronary plaques. Macrophages and T lymphocytes are considered to contribute to destabilization of the plaques. The role of mast cells in this setting is less well studied. We therefore counted the mast cells in coronary atherectomy specimens from patients with chronic stable

Maija Kaartinen; Allard C. van der Wal; Chris M. van der Loos; Jan J. Piek; Karel T. Koch; Anton E. Becker; Petri T. Kovanen



Assessment of coronary plaque collagen with polarization sensitive optical coherence tomography (PS-OCT)  

Microsoft Academic Search

IntroductionCurrent evidence indicates that most plaques classified as vulnerable or ruptured plaque do not lead to unstable angina or myocardial infarction. Improved methods are needed to risk stratify plaques to identify those which lead to most acute coronary syndromes. Collagen depletion in the intima overlying lipid collections appears to be a critical component of unstable plaques. In this study, we

Susanne D. Giattina; Brian K. Courtney; Paul R. Herz; Michelle Harman; Sonya Shortkroff; Debra L. Stamper; Bin Liu; James G. Fujimoto; Mark E. Brezinski



Atherosclerosis and Atheroma Plaque Rupture: Normal Anatomy of Vasa Vasorum and Their Role Associated with Atherosclerosis  

PubMed Central

Atherosclerosis is primarily a degenerative disorder related to aging with a chronic inflammatory component. There are differences in expression among different vascular beds, inflicting a range of vascular diseases. The majority of studies focus on the inner and medial vascular layers, which are affected at the development of atherosclerosis. Recent evidence shows that the outer layer of blood vessels, composed of the adventitial layer and the vasa vasorum, not only plays a significant role in maintaining vessel integrity, but also reacts to atheroma. What is not clear is the extent of contribution of the outer layer to the process of atherosclerosis. Is it involved in the initiation, progression, and clinical expression of atheroma? Is the inflammation associated with atheroma limited to being merely reactive or is there a proactive element? This paper provides an overview of the normal anatomy of vasa vasorum and potential mechanism of plaque formation due to vascular injury (vasa vasorum) and microhemorrhage. PMID:24790560



Evaluation of Fibrous Cap Rupture of Atherosclerotic Carotid Plaque with Thin-Slice Source Images of Time-of-Flight MR Angiography  

PubMed Central

Objective: To investigate the ability of source image of time-of-flight magnetic resonance angiography (TOF-MRA) in the detection of fibrous cap rupture of atherosclerotic carotid plaques. Materials and Methods: From the database of radiological information in our hospital, 35 patients who underwent carotid MR imaging and subsequent carotid endoarterectomy within 2 weeks were included in this retrospective study. MR imaging included thin-slice time-of-flight MR angiography, black-blood T1- and T2-weighted imaging. Sensitivity, specificity and accuracy were calculated for the detection of fibrous cap rupture with source image of TOF-MRA. The Cohen k coefficient was also calculated to quantify the degree of concordance of source image of TOF-MRA with histopathological data. Results: Sensitivity, specificity and accuracy in the detection of fibrous cap rupture were 90% (95%CI: 81–98), 69% (95%CI: 56–82) and 79% (95%CI: 71–87) with a k value of 0.59. The false positives (n = 15) were caused by partial-volume averaging between fibrous cap and lumen at the shoulder of carotid plaque. The false negatives (n = 5) were underestimated as partial thinning of fibrous cap. Conclusion: Source image of TOF-MRA can be useful in the detection of fibrous cap rupture with high sensitivity, but further technical improvement should be necessary to overcome shortcomings causing image degradation. PMID:24995056



Current Computed Tomography Techniques Can Detect Duct of Bellini Plugging but not Randall's Plaques  

PubMed Central

Objectives To assess the ability of noninvasive computed tomography (CT) scans to detect interstitial calcium phosphate deposits (Randall's plaques) and duct of Bellini plugs, which are possible stone precursor lesions. Methods At time of percutaneous nephrolithotomy (PCNL) for stone removal, all accessible individual papillae of 105 patients were endoscopically visualized and video recorded. Image processing software was used to estimate the percentage papillary surface occupied by plaque or plug in each pole (upper, mid, lower). The location of stones was also recorded. A radiologist blinded to the mapping results scored pre surgical (n=98) and post surgical (n=105) abdominal CT scans for the presence or absence of calcification by pole. Results Mean age of the cohort was 56 years [range 23-84]. Maximum papillary surface area of each area of the kidney occupied by plug correlated with CT calcifications on both pre and post procedure images by rank sum test. However, maximum plaque surface area did not correlate with radiographic findings (p range from 0.10-0.90 for each pole by rank sum test). Sensitivity and specificity of CT to detect plugs of at least 1% of the papillary surface area was 81% and 69%, respectively. Conclusion Calcifications seen on current generation clinical CT scans correspond to ductal plugging involving at least 1% of the papillary surface area. Current clinical CT scan technology appears inadequate for detecting Randall's plaques. PMID:23791212

Krambeck, Amy E.; Lieske, John C.; Li, Xujian; Bergstralh, Eric J.; Rule, Andrew D.; Holmes, David; McCollough, Cynthia. M; Vrtiska, Terri J.



Magnetic Resonance Imaging to Identify Intraplaque Hemorrhage and Define its Location in Complicated Carotid Artery Plaques.  

E-print Network

??Atherosclerotic plaque (AP) composition is an important factor influencing plaque rupture. Intraplaque hemorrhage (IPH) is a marker of complicated-plaque formation, responsible for many of the… (more)

Bitar, Richard



Progress in atherosclerotic plaque imaging  

PubMed Central

Cardiovascular diseases are the primary cause of mortality in the industrialized world, and arterial obstruction, triggered by rupture-prone atherosclerotic plaques, lead to myocardial infarction and cerebral stroke. Vulnerable plaques do not necessarily occur with flow-limiting stenosis, thus conventional luminographic assessment of the pathology fails to identify unstable lesions. In this review we discuss the currently available imaging modalities used to investigate morphological features and biological characteristics of the atherosclerotic plaque. The different imaging modalities such as ultrasound, magnetic resonance imaging, computed tomography, nuclear imaging and their intravascular applications are illustrated, highlighting their specific diagnostic potential. Clinically available and upcoming methodologies are also reviewed along with the related challenges in their clinical translation, concerning the specific invasiveness, accuracy and cost-effectiveness of these methods. PMID:22937215

Soloperto, Giulia; Casciaro, Sergio



Inflammation and Plaque Vulnerability  

Microsoft Academic Search

Development of a thrombus at the site of an atherosclerotic plaque initiates abrupt arterial occlusion and is the proximate\\u000a event responsible for the vast majority of acute ischemic syndromes. In nearly 75% of cases thrombus overlies a disrupted\\u000a or ruptured plaque whereas the remainder of the thrombi overly an intact plaque with superficial endothelial erosion. Over\\u000a the past several years,

Prediman K. Shah



High Field Atherosclerotic Plaque MRI  

PubMed Central

Manifestations of atherosclerotic plaque in different arterial beds range from perfusion deficits to overt ischemia such as stroke and myocardial infarction. Atherosclerotic plaque composition is known to be associated with its propensity to rupture and cause vascular events. MRI of atherosclerotic plaque using clinical 1.5T scanners can detect plaque composition. Plaque MRI at higher field strengths offers both opportunities and challenges to improving the high spatial-resolution and contrast required for this type of imaging. This article summarizes the technological requirements required for high field plaque MRI and its application in detecting plaque components. PMID:22548932

Yuan, Chun; Wang, Jinnan; Balu, Niranjan



Biomarkers of plaque instability.  


Atherosclerosis is the proximate cause of arterial thrombosis, leading to acute occlusive cardiovascular syndromes. Thrombosis in atherosclerosis usually results from rupture of the fibrous cap of atherosclerotic plaques with a smaller proportion resulting from superficial endothelial erosion. Ruptured plaques are often associated with intimal and adventitial inflammation, increased size of lipid-rich necrotic core with thinned out collagen-depleted fibrous cap, outward remodeling, increased plaque neovascularity, intraplaque hemorrhage, and microcalcification. By inference, non-ruptured plaques with similar compositional features are considered to be at risk for rupture and hence are labeled vulnerable plaques or high-risk plaques. Identification of vulnerable plaques may help in predicting the risk of acute occlusive syndromes and may also allow targeting for aggressive systemic and possibly local therapies. Plaque rupture is believed to result from extracellular matrix (which comprises the protective fibrous cap) dysregulation due to excessive proteolysis in the context of diminished matrix synthesis. Inflammation is believed to play a key role by providing matrix-degrading metalloproteinases and also by inducing death of matrix-synthesizing smooth muscle cells. Systemic markers of inflammation are thus the most logical forms of potential biomarkers which may predict the presence of vulnerable or high-risk plaques. Several studies have suggested the potential prognostic value of a variety of systemic markers, but regrettably, their overall clinical predictive value is modestly incremental at best, especially for individual subjects compared to groups of patients. Nevertheless, continued investigation of reliable, cost-effective biomarkers that predict the presence of a high-risk plaque and future athero-thrombotic cardiovascular events with greater sensitivity and specificity is warranted. PMID:25326730

Shah, P K



Monocytes and neutrophils expressing myeloperoxidase occur in fibrous caps and thrombi in unstable coronary plaques  

Microsoft Academic Search

BACKGROUND: Myeloperoxidase (MPO) -containing macrophages and neutrophils have been described at sites of plaque rupture. The presence of these cells in precursor lesions to acute rupture (thin cap atheroma, or vulnerable plaque) and within thrombi adjacent to ruptures has not been described, nor an association with iron-containing macrophages within unstable plaques. METHODS: We studied 61 acute ruptures, 15 organizing ruptures,

Fabio R Tavora; Mary Ripple; Ling Li; Allen P Burke



Inflammation of the Atherosclerotic Cap and Shoulder of the Plaque Is a Common and Locally Observed Feature in Unruptured Plaques of Femoral and Coronary Arteries  

Microsoft Academic Search

Retrospectively, plaque rupture is often colocalized with inflammation of the cap and shoulder of the atherosclerotic plaque. Local inflammation is therefore considered a potential marker for plaque vulnerability. However, high specificity of inflammation for plaque rupture is a requisite for application of inflammation markers to detect rupture-prone lesions. The objective of the present study was to investigate the prevalence and

Gerard Pasterkamp; Arjan H. Schoneveld; Allard C. van der Wal; Dirk-Jan Hijnen; Willem J. A. van Wolveren; Simon Plomp; Hans L. J. M. Teepen; Cornelius Borst


Characterization of Atherosclerotic Plaques by Laser Speckle Imaging  

Microsoft Academic Search

Background—A method capable of determining atherosclerotic plaque composition and measuring plaque viscoelasticity can provide valuable insight into intrinsic features associated with plaque rupture and can enable the identification of high-risk lesions. In this article, we describe a new optical technique, laser speckle imaging (LSI), that measures an index of plaque viscoelasticity. We evaluate the potential of LSI for characterizing atherosclerotic

Seemantini K. Nadkarni; Brett E. Bouma; Tina Helg; Raymond Chan; Elkan Halpern; Alexandra Chau; Milan Singh Minsky; Jason T. Motz; Stuart L. Houser; Guillermo J. Tearney



Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque  

E-print Network

Early detection and treatment of rupture-prone vulnerable atherosclerotic plaques is critical to reducing patient mortality associated with cardiovascular disease. The combination of reflectance, fluorescence, and Raman ...

Scepanovic, Obrad R.


Visualization of Fibrous Cap Thickness and Rupture in Human Atherosclerotic Carotid Plaque In Vivo With High-Resolution Magnetic Resonance Imaging  

Microsoft Academic Search

Background—The results of studies of advanced lesions of atherosclerosis suggest that the thickness of the fibrous cap that overlies the necrotic core distinguishes the stable lesion from one that is at high risk for rupture and thromboembolic events. We have developed a high-resolution MRI technique that can identify the fine structure of the lesion, including the fibrous cap, in vivo.

Thomas S. Hatsukami; Russell Ross; Nayak L. Polissar; Chun Yuan


Thermal study of vulnerable atherosclerotic plaque  

E-print Network

Atherosclerotic plaques with high probability of rupture show the presence of a hot spot due to the accumulation of inflammatory cells. This study utilizes two and three dimensional (2-D and 3-D) arterial geometries containing an atherosclerotic...

Kim, Taehong



The vulnerable coronary plaque: update on imaging technologies.  


Several studies have been carried out on vulnerable plaque as the main culprit for ischaemic cardiac events. Historically, the most important diagnostic technique for studying coronary atherosclerotic disease was to determine the residual luminal diameter by angiographic measurement of the stenosis. However, it has become clear that vulnerable plaque rupture as well as thrombosis, rather than stenosis, triggers most acute ischaemic events and that the quantification of risk based merely on severity of the arterial stenosis is not sufficient. In the last decades, substantial progresses have been made on optimisation of techniques detecting the arterial wall morphology, plaque composition and inflammation. To date, the use of a single technique is not recommended to precisely identify the progression of the atherosclerotic process in human beings. In contrast, the integration of data that can be derived from multiple methods might improve our knowledge about plaque destabilisation. The aim of this narrative review is to update evidence on the accuracy of the currently available non-invasive and invasive imaging techniques in identifying components and morphologic characteristics associated with coronary plaque vulnerability. PMID:23803753

Rosa, Gian Marco; Bauckneht, Matteo; Masoero, Giovanni; Mach, François; Quercioli, Alessandra; Seitun, Sara; Balbi, Manrico; Brunelli, Claudio; Parodi, Antonello; Nencioni, Alessio; Vuilleumier, Nicolas; Montecucco, Fabrizio



Radionuclide imaging - A molecular key to the atherosclerotic plaque  

PubMed Central

Despite primary and secondary prevention, serious cardiovascular events like unstable angina or myocardial infarction still account for one third of all deaths worldwide. Therefore, identifying individual patients with vulnerable plaques at high risk for plaque rupture is a central challenge in cardiovascular medicine. Several non-invasive techniques, such as MRI, multislice computed tomography and electron beam tomography are currently being tested for their ability to identify such patients by morphological criteria. In contrast, molecular imaging techniques use radiolabeled molecules to detect functional aspects in atherosclerotic plaques by visualizing its biological activity. Based upon the knowledge about the pathophysiology of atherosclerosis, various studies in vitro, in vivo and the first clinical trials have used different tracers for plaque imaging studies, including radioactive labelled lipoproteins, components of the coagulation system, cytokines, mediators of the metalloproteinase system, cell adhesion receptors and even whole cells. This review gives an update on the relevant non-invasive plaque imaging approaches using nuclear imaging techniques to detect atherosclerotic vascular lesions. PMID:18582628

Langer, Harald Franz; Haubner, Roland; Pichler, Bernd Juergen; Gawaz, Meinrad



Ultrasonic tissue characterization of collagen in lipid-rich plaques in apoE-deficient mice  

Microsoft Academic Search

Mechanical failure of the fibrous cap of a vulnerable atherosclerotic plaque may lead to sudden plaque rupture and thus precipitate arterial thrombosis. Because ultrasound correlates strongly with mechanical features of tissues it might provide information on the stability of fibrous caps. The acoustic properties of the normal vessel wall and plaques, particularly fibrous caps of lipid-rich plaques, were evaluated in

Yoshifumi Saijo; Claus Schiøtt Jørgensen; Erling Falk



Vulnerable Plaque  


... within an artery leading to the heart or brain. With time, the plaque buildup would narrow the artery so much that the artery would either close off or become clogged by a blood clot (much like a clogged drain). The lack of oxygen-rich blood to the ...


Fishbowl Plaques.  

ERIC Educational Resources Information Center

Presents an elementary art activity that successfully teaches the process of slabbing by having students create fishbowl plaques. Explains the process step-by-step beginning with a demonstration to the students along with showing previous examples. Endorses a type of clay that fires white because the glaze colors are much more vibrant. (CMK)

Lambert, Phyllis Gilchrist



Haemodynamical stress in mouse aortic arch with atherosclerotic plaques: Preliminary study of plaque progression  

PubMed Central

Atherosclerotic plaques develop at particular sites in the arterial tree, and this regional localisation depends largely on haemodynamic parameters (such as wall shear stress; WSS) as described in the literature. Plaque rupture can result in heart attack or stroke and hence understanding the development and vulnerability of atherosclerotic plaques is critically important. The purpose of this study is to characterise the haemodynamics of blood flow in the mouse aortic arch using numerical modelling. The geometries are digitalised from synchrotron imaging and realistic pulsatile blood flow is considered under rigid wall assumptions. Two cases are considered; arteries with and without plaque. Mice that are fed under fat diet present plaques in the aortic arch whose size is dependent on the number of weeks under the diet. The plaque distribution in the region is however relatively constant through the different samples. This result underlines the influence of the geometry and consequently of the wall shear stresses for plaque formation with plaques growing in region of relative low shear stresses. A discussion of the flow field in real geometry in the presence and absence of plaques is conducted. The presence of plaques was shown to alter the blood flow and hence WSS distribution, with regions of localised high WSS, mainly on the wall of the brachiocephalic artery where luminal narrowing is most pronounced. In addition, arch plaques are shown to induce recirculation in the blood flow, a phenomenon with potential influence on the progression of the plaques. The oscillatory shear index and the relative residence time have been calculated on the geometry with plaques to show the presence of this recirculation in the arch, an approach that may be useful for future studies on plaque progression. PMID:25349678

Assemat, P.; Siu, K.K.; Armitage, J.A.; Hokke, S.N.; Dart, A.; Chin-Dusting, J.; Hourigan, K.



Assessment of vulnerable plaque composition by matching the deformation of a parametric plaque model to measured plaque deformation  

Microsoft Academic Search

Intravascular ultrasound (IVUS) elastography visualizes local radial strain of arteries in so-called elastograms to detect rupture-prone plaques. However, due to the unknown arterial stress distribution these elastograms cannot be directly interpreted as a morphology and material composition image. To overcome this limitation we have developed a method that reconstructs a Young's modulus image from an elastogram. This method is especially

Radj A. Baldewsing; Johannes A. Schaar; Frits Mastik; Cees. W. J. Oomens; Antonius F. W. van der Steen



Nanoplasmonically-induced defects in lipid membrane monitored by ion current: transient nanopores versus membrane rupture.  


We have developed a nanoplasmonic-based approach to induce nanometer-sized local defects in the phospholipid membranes. Here, gold nanorods and nanoparticles having plasmon resonances in the near-infrared (NIR) spectral range are used as optical absorption centers in the lipid membrane. Defects optically induced by NIR-laser irradiation of gold nanoparticles are continuously monitored by high-precision ion conductance measurement. Localized laser-mediated heating of nanorods and nanoparticle aggregates cause either (a) transient nanopores in lipid membranes or (b) irreversible rupture of the membrane. To monitor transient opening and closing, an electrophysiological setup is assembled wherein a giant liposome is spread over a micrometer hole in a glass slide forming a single bilayer of high Ohmic resistance (so-called gigaseal), while laser light is coupled in and focused on the membrane. The energy associated with the localized heating is discussed and compared with typical elastic parameters in the lipid membranes. The method presented here provides a novel methodology for better understanding of transport across artificial or natural biological membranes. PMID:24961609

Palankar, Raghavendra; Pinchasik, Bat-El; Khlebtsov, Boris N; Kolesnikova, Tatiana A; Möhwald, Helmuth; Winterhalter, Mathias; Skirtach, Andre G



Effects of intima stiffness and plaque morphology on peak cap stress  

Microsoft Academic Search

Background  Rupture of the cap of a vulnerable plaque present in a coronary vessel may cause myocardial infarction and death. Cap rupture\\u000a occurs when the peak cap stress exceeds the cap strength. The mechanical stress within a cap depends on the plaque morphology\\u000a and the material characteristics of the plaque components. A parametric study was conducted to assess the effect of

Ali C Akyildiz; Lambert Speelman; Harald van Brummelen; Miguel A Gutiérrez; Renu Virmani; Aad van der Lugt; Anton FW van der Steen; Jolanda J Wentzel; Frank JH Gijsen



Vascular MR segmentation: wall and plaque  

NASA Astrophysics Data System (ADS)

Cardiovascular events frequently result from local rupture of vulnerable atherosclerotic plaque. Non-invasive assessment of plaque vulnerability is needed to allow institution of preventive measures before heart attack or stroke occur. A computerized method for segmentation of arterial wall layers and plaque from high-resolution volumetric MR images is reported. The method uses dynamic programming to detect optimal borders in each MRI frame. The accuracy of the results was tested in 62 T1-weighted MR images from 6 vessel specimens in comparison to borders manually determined by an expert observer. The mean signed border positioning errors for the lumen, internal elastic lamina, and external elastic lamina borders were -0.12+/-0.14 mm, 0.04+/-0.12mm, and -0.15+/-0.13 mm, respectively. The presented wall layer segmentation approach is one of the first steps towards non-invasive assessment of plaque vulnerability in atherosclerotic subjects.

Yang, Fuxing; Holzapfel, Gerhard; Schulze-Bauer, Christian; Stollberger, Rudolf; Thedens, Daniel; Bolinger, Lizann; Stolpen, Alan; Sonka, Milan



Radiolabelled probes for imaging of atherosclerotic plaques  

PubMed Central

Cardiovascular disease is the leading cause of death worldwide. Unstable atherosclerotic plaques are prone to rupture followed by thrombus formation, vessel stenosis, and occlusion and frequently lead to acute myocardial infarction and brain infarction. As such, unstable plaques represent an important diagnostic target in clinical settings and the specific diagnosis of unstable plaques would enable preventive treatments for cardiovascular disease. To date, various imaging methods such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), and intravascular ultrasound (IVUS) have been widely used clinically. Although these methods have advantages in terms of spatial resolution and the ability to make detailed identification of morphological alterations such as calcifications and vessel stenosis, these techniques require skill or expertise to discriminate plaque instability, which is essential for early diagnosis and treatment and can present difficulties for quantitative estimation. On the other hand, nuclear imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) can noninvasively collect quantitative information on the expression levels of functional molecules and metabolic activities in vivo and thus provide functional diagnoses of unstable plaques with high sensitivity. Specifically, unstable plaques are characterized by an abundance of invasive inflammatory cells (macrophages), increased oxidative stress that increases oxidized LDL and its receptor expressed on cells in the lesions, increased occurrence of apoptosis of macrophages and other cells involved in disease progression, increased protease expression and activity, and finally thrombus formation triggered by plaque rupture, which is the most important mechanism leading to the onset of infarctions and ischemic sudden death. Therefore, these characteristics can all be targets for molecular imaging by PET and SPECT. In this paper, we review the present state and future of radiolabelled probes that have been developed for detecting atherosclerotic unstable plaques with nuclear imaging techniques. PMID:23145360

Temma, Takashi; Saji, Hideo



Evaluation of collagen in atherosclerotic plaques: the use of two coherent laser-based imaging methods  

Microsoft Academic Search

Acute coronary events such as myocardial infarction are frequently caused by the rupture of unstable atherosclerotic plaque.\\u000a Collagen plays a key role in determining plaque stability. Methods to measure plaque collagen content are invaluable in detecting\\u000a unstable atherosclerotic plaques. Recently, novel coherent laser-based imaging techniques, such as polarization-sensitive\\u000a optical coherence tomography (PSOCT) and laser speckle imaging (LSI) have been investigated,

Seemantini K. Nadkarni; Brett E. Bouma; Johannes de Boer; Guillermo J. Tearney



Comprehensive overview of definitions for optical coherence tomography-based plaque and stent analyses.  


Optical coherence tomography (OCT) is the current state-of-the-art intracoronary imaging modality that allows visualization of detailed morphological characteristics of both atherosclerotic plaque and stent. So far, three expert review documents have been released for standardization of OCT image analysis. In the real world, a variety of definitions are being used by different groups and by different core laboratories to analyze OCT findings because of different clinical/procedural contexts in which OCT research has been carried out. This comprehensive overview is aimed to summarize different applicable definitions used by different research groups in plaque and stent analysis using OCT. In addition, it presents readers with a panoramic view to select the best definition of OCT measurement for one's own study purpose. We divided this review article into two parts: Part I - Plaque analysis, and Part II - Stent analysis. The plaque analysis section summarizes the definitions of plaque composition, rupture, erosion, protruding calcific nodules, macrophages, microvessels, and cholesterol crystal. The stent analysis section includes the classification of stent struts, features of neointimal hyperplasia, and other stent-related findings such as tissue protrusion, thrombus, intrastent, and stent edge dissections. In each case of controversy, an explanation for the specific context is provided. PMID:24356250

Di Vito, Luca; Yoon, Joo Heung; Kato, Koji; Yonetsu, Taishi; Vergallo, Rocco; Costa, Marco; Bezerra, Hiram G; Arbustini, Eloisa; Narula, Jagat; Crea, Filippo; Prati, Francesco; Jang, Ik-Kyung



The pathology of atherosclerosis: plaque development and plaque responses to medical treatment.  


Atherosclerosis develops over the course of 50 years, beginning in the early teenage years. The causes of this process appear to be lipid retention, oxidation, and modification, which provoke chronic inflammation at susceptible sites in the walls of all major conduit arteries. Initial fatty streaks evolve into fibrous plaques, some of which develop into forms that are vulnerable to rupture, causing thrombosis or stenosis. Erosion of the surfaces of some plaques and rupture of a plaque's calcific nodule into the artery lumen also may trigger thrombosis. The process of plaque development is the same regardless of race/ethnicity, sex, or geographic location, apparently worldwide. However, the rate of development is faster in patients with risk factors such as hypertension, tobacco smoking, diabetes mellitus, obesity, and genetic predisposition. Clinical trial data demonstrate that treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) favorably alters plaque size, cellular composition, chemical composition, and biological activities centered on inflammation and cholesterol metabolism, as well as the risk of clinical events due to atherosclerosis. Even with advanced atherosclerosis, statins begin to improve clinical risk within 4 months. During long-term follow-up in clinical trials for up to 11 years with or without further treatment, clinical benefit remains significant, indicating the durability of treatment-induced changes in the development of plaque. Thus, atherosclerosis, a disease heretofore viewed as inevitably progressive, can be treated to significantly alter arterial lesions and reduce their clinical consequences. PMID:19110086

Insull, William



Development of a quantitative mechanical test of atherosclerotic plaque stability.  


Atherosclerotic plaque rupture is the main cause of myocardial infarction and stroke. Both clinical and computational studies indicate that the shoulder region, where a plaque joins the vessel wall, is rupture-prone. Previous mechanistic studies focused on mechanical properties of the fibrous cap and tensile stresses, which could lead to tearing of the cap. Based on clinical observations of "mobile floating plaques," we postulate that de-adhesion between the fibrous cap and the underlying vessel wall may also play a role in plaque failure. Thus, measuring adhesive strength of the bond between plaque and vascular wall may provide useful new insights into plaque stability. Delamination experiments, widely used in examining inter-laminar adhesive strength of biological materials, were used to measure adhesive strength of advanced plaques in apolipoprotein E-knockout (apoE-KO) mice after 8 months on Western diet. We measured adhesive strength in terms of local energy release rate, G, during controlled plaque delamination. As a measure of the fracture energy required to delaminate a unit area of plaque from the underlying internal elastic lamina (IEL), G provides a quantitative measure of local adhesive strength of the plaque-IEL interface. The values for G acquired from 16 plaques from nine apoE-KO mouse aortas formed a positively skewed distribution with a mean of 24.5 J/m(2), median of 19.3 J/m(2), first quartile of 10.8 J/m(2), and third quartile of 34.1 J/m(2). These measurements are in the lower range of values reported for soft tissues. Histological studies confirmed delamination occurred at the interface between plaque and IEL. PMID:21757197

Wang, Ying; Ning, Jinfeng; Johnson, John A; Sutton, Michael A; Lessner, Susan M



Imaging Atherosclerosis and Vulnerable Plaque  

PubMed Central

Identifying patients at high risk for an acute cardiovascular event such as myocardial infarction or stroke and assessing the total atherosclerotic burden are clinically important. Currently available imaging modalities can delineate vascular wall anatomy and, with novel probes, target biologic processes important in plaque evolution and plaque stability. Expansion of the vessel wall involving remodeling of the extracellular matrix can be imaged, as can angiogenesis of the vasa vasorum, plaque inflammation, and fibrin deposits on early nonocclusive vascular thrombosis. Several imaging platforms are available for targeted vascular imaging to acquire information on both anatomy and pathobiology in the same imaging session using either hybrid technology (nuclear combined with CT) or MRI combined with novel probes targeting processes identified by molecular biology to be of importance. This article will discuss the current state of the art of these modalities and challenges to clinical translation. PMID:20395341

Sadeghi, Mehran M.; Glover, David K.; Lanza, Gregory M.; Fayad, Zahi A.; Johnson, Lynne L.



Small entities with large impact: microcalcifications and atherosclerotic plaque vulnerability  

PubMed Central

Purpose of review Atherosclerotic plaque rupture and subsequent acute events, such as myocardial infarction and stroke, contribute to the majority of cardiovascular-related deaths. Calcification has emerged as a significant predictor of cardiovascular morbidity and mortality, challenging previously held notions that calcifications stabilize atherosclerotic plaques. In this review, we address this discrepancy through recent findings that not all calcifications are equivalent in determining plaque stability. Recent findings The risk associated with calcification is inversely associated with calcification density. As opposed to large calcifications that potentially stabilize the plaque, biomechanical modeling indicates that small microcalcifications within the plaque fibrous cap can lead to sufficient stress accumulation to cause plaque rupture. Microcalcifications appear to derive from matrix vesicles enriched in calcium-binding proteins that are released by cells within the plaque. Clinical detection of microcalcifications has been hampered by the lack of imaging resolution required for in-vivo visualization; however, recent studies have demonstrated promising new techniques to predict the presence of microcalcifications. Summary Microcalcifications play a major role in destabilizing atherosclerotic plaques. The identification of critical characteristics that lead to instability along with new imaging modalities to detect their presence in vivo may allow early identification and prevention of acute cardiovascular events. PMID:25188916

Hutcheson, Joshua D.; Maldonado, Natalia; Aikawa, Elena



In vivo Raman spectral pathology of human atherosclerosis and vulnerable plaque  

E-print Network

The rupture of vulnerable atherosclerotic plaque accounts for the majority of clinically significant acute cardiovascular events. Because stability of these culprit lesions is directly related to chemical and morphological ...

Motz, Jason T.


Polymeric Nanoparticle PET/MR Imaging Allows Macrophage Detection in Atherosclerotic Plaques  

E-print Network

Rationale: Myeloid cell content in atherosclerotic plaques associates with rupture and thrombosis. Thus, imaging of lesional monocytes and macrophages could serve as a biomarker of disease progression and therapeutic ...

Majmudar, M. D.


Positron emission tomography of the vulnerable atherosclerotic plaque in man - a contemporary review.  


Atherosclerosis is the primary underlying cause of cardiovascular disease (CVD). It is the leading cause of morbidity and mortality in the Western world today and is set to become the prevailing disease and major cause of death worldwide by 2020. In the 1950s surgical intervention was introduced to treat symptomatic patients with high-grade carotid artery stenosis due to atherosclerosis - a procedure known as carotid endarterectomy (CEA). By removing the atherosclerotic plaque from the affected carotid artery of these patients, CEA is beneficial by preventing subsequent ipsilateral ischemic stroke. However, it is known that patients with low to intermediate artery stenosis may still experience ischemic events, leading clinicians to consider plaque composition as an important feature of atherosclerosis. Today molecular imaging can be used for characterization, visualization and quantification of cellular and subcellular physiological processes as they take place in vivo; using this technology we can obtain valuable information on atherosclerostic plaque composition. Applying molecular imaging clinically to atherosclerotic disease therefore has the potential to identify atherosclerotic plaques vulnerable to rupture. This could prove to be an important tool for the selection of patients for CEA surgery in a health system increasingly focused on individualized treatment. This review focuses on current advances and future developments of in vivo atherosclerosis PET imaging in man. PMID:24289282

Pedersen, Sune F; Hag, Anne Mette F; Klausen, Thomas L; Ripa, Rasmus S; Bodholdt, Rasmus P; Kjaer, Andreas



Reducing dental plaque formation and caries development. A review of current methods and implications for novel pharmaceuticals.  


Dental caries is an oral disease, which has a high worldwide prevalence despite the availability of various prophylactic means, including the daily use of fluoride toothpastes, water fluoridation, dental sealants, oral health educational programs and various antiseptic mouth-rinses. One important reason for this is uncontrolled increase in consumption of foods containing considerable sucrose concentration, especially among children. Sucrose is easily metabolized by oral bacteria (mostly streptococci) to acids and, subsequently, causing tooth decay or dental caries. In the oral ecosystem, streptococci principally reside on tooth surfaces forming biofilm. Important structural and binding materials of biofilm are glucan polymers synthesized by several isoforms of glucosyltransferase enzyme present in certain species of oral bacteria, including mutans group streptococci - Streptococcus mutans and Streptococcus sobrinus, which preferably colonize humans. Thus, there is a constant need to develop the methods and chemotherapeutics for improving oral health care and decreasing teeth decay through the suppression of cariogenic biofilm formation in the oral cavity. The aim of this paper was to review literature related to the pathogenesis of dental caries as well as currently existing and experimental pharmaceutical substances used for prevention of this process. PMID:25209226

Kalesinskas, Povilas; Ka?ergius, Tomas; Ambrozaitis, Arvydas; Pe?iulien?, Vytaut?; Ericson, Dan



Relation of arterial geometry to luminal narrowing and histologic markers for plaque vulnerability: the remodeling paradox  

Microsoft Academic Search

Objective. To relate local arterial geometry with markers that are thought to be related to plaque rupture.Background. Plaque rupture often occurs at sites with minor luminal stenosis and has retrospectively been characterized by colocalization of inflammatory cells. Recent studies have demonstrated that luminal narrowing is related with the mode of atherosclerotic arterial remodeling.Methods. We obtained 1,521 cross section slices at

Gerard Pasterkamp; Arjan H Schoneveld; Allard C van der Wal; Christian C Haudenschild; Ruud J. G Clarijs; Anton E Becker; Berend Hillen; Cornelius Borst



Macrophage expression of active MMP-9 induces acute plaque disruption in apoE-deficient mice  

PubMed Central

The majority of acute clinical manifestations of atherosclerosis are due to the physical rupture of advanced atherosclerotic plaques. It has been hypothesized that macrophages play a key role in inducing plaque rupture by secreting proteases that destroy the extracellular matrix that provides physical strength to the fibrous cap. Despite reports detailing the expression of multiple proteases by macrophages in rupture-prone regions, there is no direct proof that macrophage-mediated matrix degradation can induce plaque rupture. We aimed to test this hypothesis by retrovirally overexpressing the candidate enzyme MMP-9 in macrophages of advanced atherosclerotic lesions of apoE–/– mice. Despite a greater than 10-fold increase in the expression of MMP-9 by macrophages, there was only a minor increase in the incidence of plaque fissuring. Subsequent analysis revealed that macrophages secrete MMP-9 predominantly as a proform, and this form is unable to degrade the matrix component elastin. Expression of an autoactivating form of MMP-9 in macrophages in vitro greatly enhances elastin degradation and induces significant plaque disruption when overexpressed by macrophages in advanced atherosclerotic lesions of apoE–/– mice in vivo. These data show that enhanced macrophage proteolytic activity can induce acute plaque disruption and highlight MMP-9 as a potential therapeutic target for stabilizing rupture-prone plaques. PMID:16374516

Gough, Peter J.; Gomez, Ivan G.; Wille, Paul T.; Raines, Elaine W.



Measurement of fibrous cap thickness in atherosclerotic plaques by spatiotemporal analysis of laser speckle images  

Microsoft Academic Search

Necrotic-core fibroatheromas (NCFA) with thin, mechanically weak fibrous caps overlying lipid cores comprise the majority of plaques that rupture and cause acute myocardial infarction. Laser speckle imaging (LSI) has been recently demonstrated to enable atherosclerotic plaque characterization with high accuracy. We investigate spatio-temporal analysis of LSI data, in conjunction with diffusion theory and Monte Carlo modeling of light transport, to

Seemantini K. Nadkarni; Alberto Bilenca; Brett E. Bouma; Guillermo J. Tearney



Humanin, a Cytoprotective Peptide, Is Expressed in Carotid Artherosclerotic Plaques in Humans  

Microsoft Academic Search

ObjectiveThe mechanism of atherosclerotic plaque progression leading to instability, rupture, and ischemic manifestation involves oxidative stress and apoptosis. Humanin (HN) is a newly emerging endogenously expressed cytoprotective peptide. Our goal was to determine the presence and localization of HN in carotid atherosclerotic plaques.Methods and ResultsPlaque specimens from 34 patients undergoing carotid endarterectomy were classified according to symptomatic history. Immunostaining combined

David G. Zacharias; Sung Gyun Kim; Alfonso Eirin Massat; Adi R. Bachar; Yun K. Oh; Joerg Herrmann; Martin Rodriguez-Porcel; Pinchas Cohen; Lilach O. Lerman; Amir Lerman



Structure-dependent dynamic mechanical behavior of fibrous caps from human atherosclerotic plaques  

Microsoft Academic Search

Background. Although thrombosis associated witha fissured atherosclerotic plaque is believed tobethemostcommon causeofacute coronarysyndromes, theunderlying factors that trigger plaque rupture arecurrently unknown. However, themechanical behavior oftheplaque isprobably ofcritical importance. Methods andResults. Totestthehypothesis thatthemechanical properties ofa plaque are dependent on itscomposition and,inparticular, thatthestiffness offibrous capschanges within therangeoffrequencies carried bya physiological pressurewave,thestress-strain relation was studied in27fibrous capsandrelated totheunderlying histological structure of thefibrous cap.Fibrous

Richard T. Lee; Alan J. Grodzinsky; Eliot H. Frank; Roger D. Kamm; Fj Schoen



The influence of genetics on intracranial aneurysm formation and rupture: current knowledge and its possible impact on future treatment  

Microsoft Academic Search

The etiology of intracranial aneurysm formation and rupture remains mostly unknown, but lately several studies have increasingly\\u000a supported the role of genetic factors. In reports so far, genome-wide linkage studies suggest several susceptibility loci\\u000a that may contain one or more predisposing genes. Depending on the examined ethnic population, several different non-matching\\u000a chromosomal regions have been found. Studies of several candidate

B. Krischek; M. Tatagiba


Th17 cells and IL-17 are involved in the disruption of vulnerable plaques triggered by short-term combination stimulation in apolipoprotein E-knockout mice.  


Considerable evidence indicates that type 1 T helper (Th1)- and Th17-mediated immune responses promote the formation of atherosclerotic plaques while that CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) have a protective effect. However, the functions of diverse CD4(+) lymphocyte subsets in plaque rupture remain poorly understood because of a shortage of satisfactory plaque rupture models. Here, we established a murine model of atherosclerotic plaque rupture using a high-fat diet and collar placement on the carotid artery, and triggered plaque rupture by short-term stimulation with a combination of lipopolysaccharide, phenylephrine injection and cold in apolipoprotein E-knockout (ApoE(-/-)) mice. We investigated the associations between Th1 cells, Th17 cells and Tregs and plaque rupture by PCR, flow cytometry, ELISA and immunohistochemistry. In total, 75% (18/24) of vulnerable plaques, but no stable plaques, showed rupture characteristics. The proportion of Th17 cells was increased among splenocytes after treatment, but the changes in the levels of Th1 cells and Tregs were not related to rupture. Furthermore, the treatment resulted in high levels of interleukin-17 (IL-17) in the serum and in the region of plaque rupture. In vitro, IL-17 increased the level of apoptosis, a major factor associated with plaque rupture, in cultured murine vascular smooth muscle cells. Th17 cells and IL-17 may be involved in the disruption of vulnerable plaques triggered by short-term stimulation with lipopolysaccharide, phenylephrine injection and cold in ApoE(-/-)mice. PMID:23542316

Ma, Tian; Gao, Qi; Zhu, Faliang; Guo, Chun; Wang, Qun; Gao, Fei; Zhang, Lining



Uterine rupture: Preventable obstetric tragedies?  

Microsoft Academic Search

Background: Although ruptured uterus is nowadays a rare obstetric emergency in Western countries, it is still alarmingly common in developing countries, where it remains a major cause of maternal mortality and morbidity. Aims: To review the recent experience of uterine rupture at a tertiary obstetric unit in eastern Nepal and to recommend improvements in the current management of labour, especially

Sangeeta K. MISHRA; Norman MORRIS; Dhruba Kumar UPRETY



Imaging of coronary atherosclerosis and identification of the vulnerable plaque  

PubMed Central

Identification of the vulnerable plaque responsible for the occurrence of acute coronary syndromes and acute coronary death is a prerequisite for the stabilisation of this vulnerable plaque. Comprehensive coronary atherosclerosis imaging in clinical practice should involve visualisation of the entire coronary artery tree and characterisation of the plaque, including the three-dimensional morphology of the plaque, encroachment of the plaque on the vessel lumen, the major tissue components of the plaque, remodelling of the vessel and presence of inflammation. Obviously, no single diagnostic modality is available that provides such comprehensive imaging and unfortunately no diagnostic tool is available that unequivocally identifies the vulnerable plaque. The objective of this article is to discuss experience with currently available diagnostic modalities for coronary atherosclerosis imaging. In addition, a number of evolving techniques will be briefly discussed. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7

de Feyter, P.J.; Serruys, P. W.; Nieman, K.; Mollet, N.; Cademartiri, F.; van Geuns, R. J.; Slager, C.; van der Steen, A.F.W.; Krams, R.; Schaar, J.A.; Wielopolski, P.; Pattynama, P.M.T.; Arampatzis, A.; van der Lugt, A.; Regar, E.; Ligthart, J.; Smits, P.



Acoustic radiation force impulse imaging of vulnerable plaques: a finite element method parametric analysis.  


Plaque rupture is the most common cause of complications such as stroke and coronary heart failure. Recent histopathological evidence suggests that several plaque features, including a large lipid core and a thin fibrous cap, are associated with plaques most at risk for rupture. Acoustic Radiation Force Impulse (ARFI) imaging, a recently developed ultrasound-based elasticity imaging technique, shows promise for imaging these features noninvasively. Clinically, this could be used to distinguish vulnerable plaques, for which surgical intervention may be required, from those less prone to rupture. In this study, a parametric analysis using Finite Element Method (FEM) models was performed to simulate ARFI imaging of five different carotid artery plaques across a wide range of material properties. It was demonstrated that ARFI imaging could resolve the softer lipid pool from the surrounding, stiffer media and fibrous cap and was most dependent upon the stiffness of the lipid pool component. Stress concentrations due to an ARFI excitation were located in the media and fibrous cap components. In all cases, the maximum Von Mises stress was<1.2 kPa. In comparing these results with others investigating plaque rupture, it is concluded that while the mechanisms may be different, the Von Mises stresses imposed by ARFI imaging are orders of magnitude lower than the stresses associated with blood pressure. PMID:23122224

Doherty, Joshua R; Dumont, Douglas M; Trahey, Gregg E; Palmeri, Mark L



Acoustic radiation force impulse imaging of vulnerable plaques: a finite element method parametric analysis  

PubMed Central

Plaque rupture is the most common cause of complications such as stroke and coronary heart failure. Recent histopathological evidence suggests that several plaque features, including a large lipid core and a thin fibrous cap, are associated with plaques most at risk for rupture. Acoustic Radiation Force Impulse (ARFI) imaging, a recently developed ultrasound-based elasticity imaging technique, shows promise for imaging these features noninvasively. Clinically, this could be used to distinguish vulnerable plaques, for which surgical intervention may be required, from those less prone to rupture. In this study, a parametric analysis using Finite-Element Method (FEM) models was performed to simulate ARFI imaging of five different carotid artery plaques across a wide range of material properties. It was demonstrated that ARFI could resolve the softer lipid pool from the surrounding, stiffer media and fibrous cap and was most dependent upon the stiffness of the lipid pool component. Stress concentrations due to an ARFI excitation were located in the media and fibrous cap components. In all cases, the maximum Von Mises stress was < 1.2 kPa. In comparing these results with others investigating plaque rupture, it is concluded that while the mechanisms may be different, the Von Mises stresses imposed by ARFI are orders of magnitude lower than the stresses associated with blood pressure. PMID:23122224

Doherty, Joshua R.; Dumont, Douglas M.; Trahey, Gregg E.; Palmeri, Mark L.



Multiaxial Mechanical Characteristics of Carotid Plaque Analysis by Multiarray Echotracking System  

Microsoft Academic Search

Background and Purpose—Carotid plaque rupture depends on the various types of mechanical stresses. Our objective was to determine the multiaxial mechanical characteristics of atherosclerotic plaque and adjacent segment of the common carotid artery. Methods—A novel noninvasive echotracking system was used to measure intima-media thickness, diameter, pulsatile strain, and distensibility at 128 sites on a 4-cm long common carotid artery segment.

Anna Paini; Pierre Boutouyrie; David Calvet; Mustapha Zidi; Enrico Agabiti-Rosei; Stephane Laurent


Dental plaque - associated infections and antibacterial oral hygiene products.  


Synopsis Dental plaque accumulates on hard non-shedding surfaces such as teeth, dentures and orthodontic appliances. This accumulation is facilitated by the absence of adequate oral hygiene procedures. The term 'plaque' describes a mass of microorganisms embedded in an organic matrix of host and microbial origin. In addition to the aesthetic desirability of 'clean teeth, healthy gums and fresh breath' associated with the absence of plaque, obvious consequences of the presence of plaque include tooth decay (dental caries), gingivitis and periodontal (gum) disease and denture associated problems. Thus the prevention of plaque formation, the reduction of plaque accumulation and the effective removal of plaque are considerations of the cosmetic and health professions alike. There are many oral hygiene products available to the general public - toothpastes, mouthwashes, denture cleaners, and, more recently, chewing gums and novel mouthwashes. Several of these products have antimicrobial components. This paper reviews the microbiology of plaque and plaque associated problems, and surveys the type of products currently available for maintenance of good oral hygiene. Potential areas for future development are also explored. PMID:19291039

Verran, J



Atherosclerotic plaque destabilization: mechanisms, models, and therapeutic strategies.  


Understanding the pathophysiology of atherogenesis and the progression of atherosclerosis have been major goals of cardiovascular research during the previous decades. However, the complex molecular and cellular mechanisms underlying plaque destabilization remain largely obscure. Here, we review how lesional cells undergo cell death and how failed clearance exacerbates necrotic core formation. Advanced atherosclerotic lesions are further weakened by the pronounced local activity of matrix-degrading proteases as well as immature neovessels sprouting into the lesion. To stimulate translation of the current knowledge of molecular mechanisms of plaque destabilization into clinical studies, we further summarize available animal models of plaque destabilization. Based on the molecular mechanisms leading to plaque instability, we outline the current status of clinical and preclinical trials to induce plaque stability with a focus on induction of dead cell clearance, inhibition of protease activity, and dampening of inflammatory cell recruitment. PMID:24385514

Silvestre-Roig, Carlos; de Winther, Menno P; Weber, Christian; Daemen, Mat J; Lutgens, Esther; Soehnlein, Oliver



Relationship of MMP-14 and TIMP-3 Expression with Macrophage Activation and Human Atherosclerotic Plaque Vulnerability  

PubMed Central

Matrix metalloproteinase-14 (MMP-14) promotes vulnerable plaque morphology in mice, whereas tissue inhibitor of metalloproteinases-3 (TIMP-3) overexpression is protective. MMP-14hi??TIMP-3lo rabbit foam cells are more invasive and more prone to apoptosis than MMP-14lo??TIMP-3hi cells. We investigated the implications of these findings for human atherosclerosis. In vitro generated macrophages and foam-cell macrophages, together with atherosclerotic plaques characterised as unstable or stable, were examined for expression of MMP-14, TIMP-3, and inflammatory markers. Proinflammatory stimuli increased MMP-14 and decreased TIMP-3 mRNA and protein expression in human macrophages. However, conversion to foam-cells with oxidized LDL increased MMP-14 and decreased TIMP-3 protein, independently of inflammatory mediators and partly through posttranscriptional mechanisms. Within atherosclerotic plaques, MMP-14 was prominent in foam-cells with either pro- or anti-inflammatory macrophage markers, whereas TIMP-3 was present in less foamy macrophages and colocalised with CD206. MMP-14 positive macrophages were more abundant whereas TIMP-3 positive macrophages were less abundant in plaques histologically designated as rupture prone. We conclude that foam-cells characterised by high MMP-14 and low TIMP-3 expression are prevalent in rupture-prone atherosclerotic plaques, independent of pro- or anti-inflammatory activation. Therefore reducing MMP-14 activity and increasing that of TIMP-3 could be valid therapeutic approaches to reduce plaque rupture and myocardial infarction. PMID:25301980

Johnson, Jason L.; Jenkins, Nicholas P.; Huang, Wei-Chun; Sala-Newby, Graciela B.; Scholtes, Vincent P. W.; Moll, Frans L.; Pasterkamp, Gerard; Newby, Andrew C.



Identifying Vulnerable Plaques with Acoustic Radiation Force Impulse Imaging  

NASA Astrophysics Data System (ADS)

The rupture of arterial plaques is the most common cause of ischemic complications including stroke, the fourth leading cause of death and number one cause of long term disability in the United States. Unfortunately, because conventional diagnostic tools fail to identify plaques that confer the highest risk, often a disabling stroke and/or sudden death is the first sign of disease. A diagnostic method capable of characterizing plaque vulnerability would likely enhance the predictive ability and ultimately the treatment of stroke before the onset of clinical events. This dissertation evaluates the hypothesis that Acoustic Radiation Force Impulse (ARFI) imaging can noninvasively identify lipid regions, that have been shown to increase a plaque's propensity to rupture, within carotid artery plaques in vivo. The work detailed herein describes development efforts and results from simulations and experiments that were performed to evaluate this hypothesis. To first demonstrate feasibility and evaluate potential safety concerns, finite- element method simulations are used to model the response of carotid artery plaques to an acoustic radiation force excitation. Lipid pool visualization is shown to vary as a function of lipid pool geometry and stiffness. A comparison of the resulting Von Mises stresses indicates that stresses induced by an ARFI excitation are three orders of magnitude lower than those induced by blood pressure. This thesis also presents the development of a novel pulse inversion harmonic tracking method to reduce clutter-imposed errors in ultrasound-based tissue displacement estimates. This method is validated in phantoms and was found to reduce bias and jitter displacement errors for a marked improvement in image quality in vivo. Lastly, this dissertation presents results from a preliminary in vivo study that compares ARFI imaging derived plaque stiffness with spatially registered composition determined by a Magnetic Resonance Imaging (MRI) gold standard in human carotid artery plaques. It is shown in this capstone experiment that lipid filled regions in MRI correspond to areas of increased displacement in ARFI imaging while calcium and loose matrix components in MRI correspond to uniformly low displacements in ARFI imaging. This dissertation provides evidence to support that ARFI imaging may provide important prognostic and diagnostic information regarding stroke risk via measurements of plaque stiffness. More generally, the results have important implications for all acoustic radiation force based imaging methods used clinically.

Doherty, Joshua Ryan


How Does Calcification Influence Plaque Vulnerability? Insights from Fatigue Analysis  

PubMed Central

Background. Calcification is commonly believed to be associated with cardiovascular disease burden. But whether or not the calcifications have a negative effect on plaque vulnerability is still under debate. Methods and Results. Fatigue rupture analysis and the fatigue life were used to evaluate the rupture risk. An idealized baseline model containing no calcification was first built. Based on the baseline model, we investigated the influence of calcification on rupture path and fatigue life by adding a circular calcification and changing its location within the fibrous cap area. Results show that 84.0% of calcified cases increase the fatigue life up to 11.4%. For rupture paths 10D far from the calcification, the life change is negligible. Calcifications close to lumen increase more fatigue life than those close to the lipid pool. Also, calcifications in the middle area of fibrous cap increase more fatigue life than those in the shoulder area. Conclusion. Calcifications may play a positive role in the plaque stability. The influence of the calcification only exists in a local area. Calcifications close to lumen may be influenced more than those close to lipid pool. And calcifications in the middle area of fibrous cap are seemly influenced more than those in the shoulder area. PMID:24955401

Wu, Baijian; Pei, Xuan; Li, Zhi-Yong



A Voxel-Map Quantitative Analysis Approach for Atherosclerotic Noncalcified Plaques of the Coronary Artery Tree  

PubMed Central

Noncalcified plaques (NCPs) are associated with the presence of lipid-core plaques that are prone to rupture. Thus, it is important to detect and monitor the development of NCPs. Contrast-enhanced coronary Computed Tomography Angiography (CTA) is a potential imaging technique to identify atherosclerotic plaques in the whole coronary tree, but it fails to provide information about vessel walls. In order to overcome the limitations of coronary CTA and provide more meaningful quantitative information for percutaneous coronary intervention (PCI), we proposed a Voxel-Map based on mathematical morphology to quantitatively analyze the noncalcified plaques on a three-dimensional coronary artery wall model (3D-CAWM). This approach is a combination of Voxel-Map analysis techniques, plaque locating, and anatomical location related labeling, which show more detailed and comprehensive coronary tree wall visualization. PMID:24348749

Li, Ying; Chen, Wei; Chen, Yonglin; Chu, Chun; Fang, Bingji; Tan, Liwen



Molecular imaging of plaques in coronary arteries with PET and SPECT.  


Coronary artery disease remains a major cause of mortality. Presence of atherosclerotic plaques in the coronary artery is responsible for lumen stenosis which is often used as an indicator for determining the severity of coronary artery disease. However, the degree of coronary lumen stenosis is not often related to compromising myocardial blood flow, as most of the cardiac events that are caused by atherosclerotic plaques are the result of vulnerable plaques which are prone to rupture. Thus, identification of vulnerable plaques in coronary arteries has become increasingly important to assist identify patients with high cardiovascular risks. Molecular imaging with use of positron emission tomography (PET) and single photon emission computed tomography (SPECT) has fulfilled this goal by providing functional information about plaque activity which enables accurate assessment of plaque stability. This review article provides an overview of diagnostic applications of molecular imaging techniques in the detection of plaques in coronary arteries with PET and SPECT. New radiopharmaceuticals used in the molecular imaging of coronary plaques and diagnostic applications of integrated PET/CT and PET/MRI in coronary plaques are also discussed. PMID:25278976

Sun, Zhong-Hua; Rashmizal, Hairil; Xu, Lei



Molecular imaging of plaques in coronary arteries with PET and SPECT  

PubMed Central

Coronary artery disease remains a major cause of mortality. Presence of atherosclerotic plaques in the coronary artery is responsible for lumen stenosis which is often used as an indicator for determining the severity of coronary artery disease. However, the degree of coronary lumen stenosis is not often related to compromising myocardial blood flow, as most of the cardiac events that are caused by atherosclerotic plaques are the result of vulnerable plaques which are prone to rupture. Thus, identification of vulnerable plaques in coronary arteries has become increasingly important to assist identify patients with high cardiovascular risks. Molecular imaging with use of positron emission tomography (PET) and single photon emission computed tomography (SPECT) has fulfilled this goal by providing functional information about plaque activity which enables accurate assessment of plaque stability. This review article provides an overview of diagnostic applications of molecular imaging techniques in the detection of plaques in coronary arteries with PET and SPECT. New radiopharmaceuticals used in the molecular imaging of coronary plaques and diagnostic applications of integrated PET/CT and PET/MRI in coronary plaques are also discussed.

Sun, Zhong-Hua; Rashmizal, Hairil; Xu, Lei



Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque  

NASA Astrophysics Data System (ADS)

Early detection and treatment of rupture-prone vulnerable atherosclerotic plaques is critical to reducing patient mortality associated with cardiovascular disease. The combination of reflectance, fluorescence, and Raman spectroscopy-termed multimodal spectroscopy (MMS)-provides detailed biochemical information about tissue and can detect vulnerable plaque features: thin fibrous cap (TFC), necrotic core (NC), superficial foam cells (SFC), and thrombus. Ex vivo MMS spectra are collected from 12 patients that underwent carotid endarterectomy or femoral bypass surgery. Data are collected by means of a unitary MMS optical fiber probe and a portable clinical instrument. Blinded histopathological analysis is used to assess the vulnerability of each spectrally evaluated artery lesion. Modeling of the ex vivo MMS spectra produce objective parameters that correlate with the presence of vulnerable plaque features: TFC with fluorescence parameters indicative of collagen presence; NC/SFC with a combination of diffuse reflectance ?-carotene/ceroid absorption and the Raman spectral signature of lipids; and thrombus with its Raman signature. Using these parameters, suspected vulnerable plaques can be detected with a sensitivity of 96% and specificity of 72%. These encouraging results warrant the continued development of MMS as a catheter-based clinical diagnostic technique for early detection of vulnerable plaques.

Š?epanovi?, Obrad R.; Fitzmaurice, Maryann; Miller, Arnold; Kong, Chae-Ryon; Volynskaya, Zoya; Dasari, Ramachandra R.; Kramer, John R.; Feld, Michael S.



Non-pulsed electrochemical impregnation of flexible metallic battery plaques  


A method of loading active battery material into porous, flexible, metallic battery plaques, comprises the following steps: precipitating nickel hydroxide active material within the plaque, by making the plaque cathodic, at a high current density, in an electro-precipitation cell also containing a consumable nickel anode and a solution comprising nickel nitrate, having a pH of between 2.0 and 2.8; electrochemically oxidizing the precipitate in caustic formation solution; and repeating the electro-precipitation step at a low current density.

Maskalick, Nicholas J. (Pittsburgh, PA)



A finite element study of balloon expandable stent for plaque and arterial wall vulnerability assessment  

NASA Astrophysics Data System (ADS)

The stresses induced within plaque tissues and arterial layers during stent expansion inside an atherosclerotic artery can be exceeded from the yield stresses of those tissues and, consequently, lead to plaque or arterial layer rupture. The distribution and magnitude of the stresses in each component involved in stenting might be clearly different for different plaque types and different arterial layers. In this study, a nonlinear finite element simulation was employed to investigate the effect of plaque composition (calcified, cellular, and hypocellular) on the stresses induced in the arterial layers (intima, media, and adventitia) during implantation of a balloon expandable coronary stent into a stenosed artery. The atherosclerotic artery was assumed to consist of a plaque and normal/healthy arterial tissues on its outer side. The results indicated a significant influence of plaque types on the maximum stresses induced within the plaque wall and arterial layers during stenting but not when computing maximum stress on the stent. The stress on the stiffest calcified plaque wall was in the fracture level (2.38 MPa), whereas cellular and hypocellular plaques remain stable owing to less stress on their walls. Regardless of plaque types, the highest von Mises stresses were observed on the stiffest intima layer, whereas the lowest stresses were seen to be located in less stiff media layer. The computed stresses on the intima layer were found to be high enough to initiate a rupture in this stiff layer. These findings suggest a higher risk of arterial vascular injury for the intima layer, while a lower risk of arterial injury for the media and adventitia layers.

Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza



Macrophage-targeted photodynamic detection of vulnerable atherosclerotic plaque  

NASA Astrophysics Data System (ADS)

Rupture of a vulnerable atherosclerotic plaque (VP) leading to coronary thrombosis is the chief cause of sudden cardiac death. VPs are angiographically insignificant lesions, which are excessively inflamed and characterized by dense macrophage infiltration, large necrotic lipid cores, thin fibrous caps, and paucity of smooth muscle cells. We have recently shown that chlorin(e6) conjugated with maleylated albumin can target macrophages with high selectivity via the scavenger receptor. We report the potential of this macrophage-targeted fluorescent probe to localize in VPs in a rabbit model of atherosclerosis, and allow detection and/or diagnosis by fluorescence spectroscopy or imaging. Atherosclerotic lesions were induced in New Zealand White rabbit aortas by balloon injury followed by administration of a high-fat diet. 24-hours after IV injection of the conjugate into atherosclerotic or normal rabbits, the animals were sacrificed, and aortas were removed, dissected and examined for fluorescence localization in plaques by fiber-based spectrofluorimetry and confocal microscopy. Dye uptake within the aortas was also quantified by fluorescence extraction of samples from aorta segments. Biodistribution of the dye was studied in many organs of the rabbits. Surface spectrofluorimetry after conjugate injection was able to distinguish between plaque and adjacent aorta, between atherosclerotic and normal aorta, and balloon-injured and normal iliac arteries with high significance. Discrete areas of high fluorescence (up to 20 times control were detected in the balloon-injured segments, presumably corresponding to macrophage-rich plaques. Confocal microscopy showed red ce6 fluorescence localized in plaques that showed abundant foam cells and macrophages by histology. Extraction data on aortic tissue corroborated the selectivity of the conjugate for plaques. These data support the strategy of employing macrophage-targeted fluorescent dyes to detect VP by intravascular spectrofluorimetry. It may also be possible to use macrophage-targeted PDT to therapeutically modify inflammatory cell-laden VPs leading to plaque stabilization and reduction of sudden cardiovascular death.

Hamblin, Michael R.; Tawakol, Ahmed; Castano, Ana P.; Gad, Faten; Zahra, Touqir; Ahmadi, Atosa; Stern, Jeremy; Ortel, Bernhard; Chirico, Stephanie; Shirazi, Azadeh; Syed, Sakeena; Muller, James E.



[Traumatic rupture of the corpus cavernosum].  


Traumatic rupture of the corpus cavernosum is relatively frequent in the authors' experience. Based on the study of a series of 80 cases and a review of the literature, the authors analyse the diagnostic and therapeutic aspects and outcome of this disease. The patients in this series had a mean age of 30 years. Meticulous and intimate clinical interview demonstrated that the commonest mechanism is forced manipulation of the erect penis (68%). Clinical examination localized the site of the fracture (proximal: 57%, distal 43%). The fracture was unilateral (78 cases), rarely bilateral (2 cases) and associated with complete rupture of the urethra (1 case). Treatment was surgical in 79 patients. A distal semicircumferential incision was used in the case of bilateral rupture, distal rupture and associated urethral lesion (34 cases). A favourable course was observed in 86% of cases. However, 9 postoperative complications (12.5%) were observed (6 cases of fibrous plaques, 3 cases of chordee of the penis), due either to the extent of the haematoma or to the delay in treatment. Traumatic rupture of the corpus cavernosum is a disease of young adults, which requires early surgical treatment with an approach adapted to the type of lesions. PMID:9834519

Bennani, S; Dakir, M; Debbagh, A; Hafiani, M; el Moussaoui, A; el Mrini, M; Benjelloun, S



Methodical study on plaque characterization using integrated vascular ultrasound, strain and spectroscopic photoacoustic imaging  

NASA Astrophysics Data System (ADS)

Carotid atherosclerosis has been identified as a potential risk factor for cerebrovascular events, but information about its direct effect on the risk of recurrent stroke is limited due to incomplete diagnosis. The combination of vascular ultrasound, strain rate and spectroscopic photoacoustics could improve the timely diagnosis of plaque status and risk of rupturing. Current ultrasound techniques can noninvasively image the anatomy of carotid arteries. The spatio-temporal variation in displacement of different regions within the arterial wall can be derived from ultrasound radio frequency data; therefore an ultrasound based strain rate imaging modality can be used to reveal changes in arterial mechanical properties. Additionally, spectroscopic photoacoustic imaging can provide information on the optical absorption properties of arterial tissue and it can be used to identify the location of specific tissue components, such as lipid pools. An imaging technique combining ultrasound, strain rate and spectroscopic photoacoustics was tested on an excised atherosclerotic rabbit aorta. The ultrasound image illustrates inhomogeneities in arterial wall thickness, the strain rate indicates the arterial segment with reduced elasticity and the spectroscopic photoacoustic image illustrates the accumulation of lipids. The results demonstrated that ultrasound, strain rate and spectroscopic photoacoustic imaging are complementary. Thus the integration of the three imaging modalities advances the characterization of atherosclerotic plaques.

Graf, Iulia M.; Su, Jimmy; Yeager, Doug; Amirian, James; Smalling, Richard; Emelianov, Stanislav



Denitrification in human dental plaque  

Microsoft Academic Search

BACKGROUND: Microbial denitrification is not considered important in human-associated microbial communities. Accordingly, metabolic investigations of the microbial biofilm communities of human dental plaque have focused on aerobic respiration and acid fermentation of carbohydrates, even though it is known that the oral habitat is constantly exposed to nitrate (NO3-) concentrations in the millimolar range and that dental plaque houses bacteria that

Frank Schreiber; Peter Stief; Armin Gieseke; Ines M Heisterkamp; Willy Verstraete; Dirk de Beer; Paul Stoodley



A double layer plaque assay using spread plate technique for enumeration of bacteriophage MS2.  


Bacteriophage MS2 is used widely as a model organism to estimate pathogenic virus survival in various environments, and is usually quantified by plaque assay. Although current plaque assays work well in enumeration of MS2 in environmental samples, quantification of MS2 calls for better visibility and higher consistency. In an attempt to improve the visibility and consistency of the current plaque assay, spread plate technique was introduced, instead of the pour plate technique used commonly in existing methods. Other parameters that influence the outcome of the plaque assay were also compared. Using spread plate technique resulted in an increase of plaque size by approximately 50% and contributed to a better visibility. Addition of supplements (glucose, CaCl2 and thiamine); reduction of agar thickness and hardness, also contributed to enhanced plaque visibility and increased plaque count. Among all the conditions tested, a supplemented thin bottom agar (10ml 1% agar) and a supplemented thin top agar (10ml 0.45% agar) with spread plate technique gave the maximum countable plaques with a minimum standard deviation. When compared to other methods, it produced significantly higher plaque count and lower variation. The optimized plaque assay significantly improved visibility and consistency of the existing plaque assay methods and could be used in quantification of MS2. PMID:24211298

Cormier, Jiemin; Janes, Marlene



Plaque Assay for Rickettsia rickettsii  

PubMed Central

A plaque technique for the assay of Rickettsia rickettsii is described. The method employs primary chick or green monkey kidney monolayer cell cultures with either an agarose or special Noble agar overlay. Plaques were counted in 6 days and resultant titers correlated well with ld50 end points obtained by a standard assay in embryonated eggs. Identification of the plaque-forming organisms was accomplished by direct observation of rickettsiae-like bodies in the monolayer lesions, inhibition of plaques by antibiotics, sensitivity of plaques to specific immune serum, and failure to cultivate other microorganisms from the infected cells. Versatility of the test was demonstrated by assaying samples of rickettsiae from several different sources commonly used in our laboratory. These included infected yolk sacs, various cell cultures, and infected guinea pig tissue. Sufficient numbers of viable rickettsiae were present in the cells of a single lesion to permit direct recovery. Images PMID:4977475

Weinberg, Edmund H.; Stakebake, Jack R.; Gerone, Peter J.



Plaque assay for Rickettsia rickettsii.  


A plaque technique for the assay of Rickettsia rickettsii is described. The method employs primary chick or green monkey kidney monolayer cell cultures with either an agarose or special Noble agar overlay. Plaques were counted in 6 days and resultant titers correlated well with ld(50) end points obtained by a standard assay in embryonated eggs. Identification of the plaque-forming organisms was accomplished by direct observation of rickettsiae-like bodies in the monolayer lesions, inhibition of plaques by antibiotics, sensitivity of plaques to specific immune serum, and failure to cultivate other microorganisms from the infected cells. Versatility of the test was demonstrated by assaying samples of rickettsiae from several different sources commonly used in our laboratory. These included infected yolk sacs, various cell cultures, and infected guinea pig tissue. Sufficient numbers of viable rickettsiae were present in the cells of a single lesion to permit direct recovery. PMID:4977475

Weinberg, E H; Stakebake, J R; Gerone, P J



Spontaneous Kidney Allograft Rupture  

Microsoft Academic Search

Spontaneous renal allograft rupture is one of the most dangerous complications of kidney transplantation, which can result in graft loss.This condition needs immediate surgical intervention. Conservative management has dismal results. Its prevalence varies from 0.3% to 3%. Rupture occurs in first few weeks after transplantation. Predisposing factors for graft rupture are acute rejection, acute tubular necrosis, and renal vein thrombosis.

H. Shahrokh; H. Rasouli; M. A. Zargar; K. Karimi; K. Zargar



Self-Rupturing Hermetic Valve  

NASA Technical Reports Server (NTRS)

For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self-energizing and requires low force compared to current pyrotechnic-based burst disk hermetic valves. This is a novel design for producing a single-use, self-rupturing, hermetically sealed valve for isolation of pressurized gas and/or liquids. This design can also be applied for single-use disposable valves for chemical instruments. A welded foil diaphragm is fully supported by two mated surfaces that are machined to micron accuracies using EDM. To open the valve, one of the surfaces is moved relative to the other to (a) remove the support creating an unsupported diaphragm that ruptures due to over pressure, and/or (b) produce tension in the diaphragm and rupture it.

Tucker, Curtis E., Jr.; Sherrit, Stewart



Intravascular photoacoustic imaging: a new tool for vulnerable plaque identification.  


The vulnerable atherosclerotic plaque is believed to be at the root of the majority of acute coronary events. Even though the exact origins of plaque vulnerability remain elusive, the thin-cap fibroatheroma, characterized by a lipid-rich necrotic core covered by a thin fibrous cap, is considered to be the most prominent type of vulnerable plaque. No clinically available imaging technique can characterize atherosclerotic lesions to the extent needed to determine plaque vulnerability prognostically. Intravascular photoacoustic imaging (IVPA) has the potential to take a significant step in that direction by imaging both plaque structure and composition. IVPA is a natural extension of intravascular ultrasound that adds tissue type specificity to the images. IVPA utilizes the optical contrast provided by the differences in the absorption spectra of plaque components to image composition. Its capability to image lipids in human coronary atherosclerosis has been shown extensively ex vivo and has recently been translated to an in vivo animal model. Other disease markers that have been successfully targeted are calcium and inflammatory markers, such as macrophages and matrix metalloproteinase; the latter two through application of exogenous contrast agents. By simultaneously displaying plaque morphology and composition, IVPA can provide a powerful prognostic marker for disease progression, and as such has the potential to transform the current practice in percutaneous coronary intervention. PMID:24631379

Jansen, Krista; van Soest, Gijs; van der Steen, Antonius F W



Composition and genesis of calcium deposits in atheroma plaques.  


The composition of atheromatous plaque determines its progression toward rupture or thrombosis. Although its histopathological structure has been widely studied, little attention has been paid to its structural and chemical composition and even less to its mineral component. Thirty-three atheromatous plaques were obtained by carotid thromboendarterectomy. Three types of materials were observed under polarized light microscopy: apatite crystals in the form of glomeruli (dark with plane polarized illumination and greensh with cross-polarized illumination); fibrous-like cholesterol (uncolored or grayish with plane-polarized illumination); and amorphous organic material as brownish deposits. SEM-EDX analysis showed an abundance of phosphorus and calcium in sufficient quantities to form calcium phosphates, and appreciably reduced levels of sodium. X-ray diffraction results differentiated samples into three groups: group I with predominance of hydroxyapatite-type crystals, group II with crystalline material containing an amorphous component, and group III with wholly amorphous material. The most abundant mineral in atheromatous plaque is hydroxyapatite, on which crystals of cholesterol and lipid nuclei are deposited, stratifying the plaque into layers that reflect the different stages of its formation. The difference in calcium and sodium concentrations between arteries with and without atheromata may indicate an important relationship in the pathophysiological development of calcium deposits. PMID:24134634

Lara, María Jesús; Ros, Eduardo; Sierra, Manuel; Dorronsoro, Carlos; Aguilar, José



Will 18F-sodium fluoride PET-CT imaging be the magic bullet for identifying vulnerable coronary atherosclerotic plaques?  


Myocardial infarction remains the commonest cause of premature death worldwide with coronary atherosclerotic plaque rupture often initiating the event. Despite an ever-expanding repertoire of cardiovascular imaging techniques, the race is still on to identify atherosclerotic lesions at high-risk of rupture: the so-called vulnerable plaque. Conventional imaging modalities such as stress testing and coronary angiography have consistently failed to identify such plaques, leading to the increasing appreciation that plaque rupture relates to factors other than just the degree of luminal stenosis. Indeed the focus has recently shifted to molecular imaging, in an attempt to directly target the pathological disease processes leading to rupture and thereby localize high-risk lesions. Histological data indicate that inflammation, necrosis and early stage microcalcification are key imaging targets by which to achieve this aim. Here, we discuss how these processes are related, focusing on the rationale and evidence supporting 18F-fluoride positron emission tomography as a novel non-invasive imaging technique for the identification of vulnerable atherosclerotic plaque. PMID:25103772

Joshi, Nikhil V; Vesey, Alex; Newby, David E; Dweck, Marc R



Painting blood vessels and atherosclerotic plaques with an adhesive drug depot  

PubMed Central

The treatment of diseased vasculature remains challenging, in part because of the difficulty in implanting drug-eluting devices without subjecting vessels to damaging mechanical forces. Implanting materials using adhesive forces could overcome this challenge, but materials have previously not been shown to durably adhere to intact endothelium under blood flow. Marine mussels secrete strong underwater adhesives that have been mimicked in synthetic systems. Here we develop a drug-eluting bioadhesive gel that can be locally and durably glued onto the inside surface of blood vessels. In a mouse model of atherosclerosis, inflamed plaques treated with steroid-eluting adhesive gels had reduced macrophage content and developed protective fibrous caps covering the plaque core. Treatment also lowered plasma cytokine levels and biomarkers of inflammation in the plaque. The drug-eluting devices developed here provide a general strategy for implanting therapeutics in the vasculature using adhesive forces and could potentially be used to stabilize rupture-prone plaques. PMID:23236189

Kastrup, Christian J.; Nahrendorf, Matthias; Figueiredo, Jose Luiz; Lee, Haeshin; Kambhampati, Swetha; Lee, Timothy; Cho, Seung-Woo; Gorbatov, Rostic; Iwamoto, Yoshiko; Dang, Tram T.; Dutta, Partha; Yeon, Ju Hun; Cheng, Hao; Pritchard, Christopher D.; Vegas, Arturo J.; Siegel, Cory D.; MacDougall, Samantha; Okonkwo, Michael; Thai, Anh; Stone, James R.; Coury, Arthur J.; Weissleder, Ralph; Langer, Robert; Anderson, Daniel G.



Painting blood vessels and atherosclerotic plaques with an adhesive drug depot.  


The treatment of diseased vasculature remains challenging, in part because of the difficulty in implanting drug-eluting devices without subjecting vessels to damaging mechanical forces. Implanting materials using adhesive forces could overcome this challenge, but materials have previously not been shown to durably adhere to intact endothelium under blood flow. Marine mussels secrete strong underwater adhesives that have been mimicked in synthetic systems. Here we develop a drug-eluting bioadhesive gel that can be locally and durably glued onto the inside surface of blood vessels. In a mouse model of atherosclerosis, inflamed plaques treated with steroid-eluting adhesive gels had reduced macrophage content and developed protective fibrous caps covering the plaque core. Treatment also lowered plasma cytokine levels and biomarkers of inflammation in the plaque. The drug-eluting devices developed here provide a general strategy for implanting therapeutics in the vasculature using adhesive forces and could potentially be used to stabilize rupture-prone plaques. PMID:23236189

Kastrup, Christian J; Nahrendorf, Matthias; Figueiredo, Jose Luiz; Lee, Haeshin; Kambhampati, Swetha; Lee, Timothy; Cho, Seung-Woo; Gorbatov, Rostic; Iwamoto, Yoshiko; Dang, Tram T; Dutta, Partha; Yeon, Ju Hun; Cheng, Hao; Pritchard, Christopher D; Vegas, Arturo J; Siegel, Cory D; MacDougall, Samantha; Okonkwo, Michael; Thai, Anh; Stone, James R; Coury, Arthur J; Weissleder, Ralph; Langer, Robert; Anderson, Daniel G



Identification of amyloid plaques in retinas from Alzheimer's patients and noninvasive in vivo optical imaging of retinal plaques in a mouse model.  


Noninvasive monitoring of ?-amyloid (A?) plaques, the neuropathological hallmarks of Alzheimer's disease (AD), is critical for AD diagnosis and prognosis. Current visualization of A? plaques in brains of live patients and animal models is limited in specificity and resolution. The retina as an extension of the brain presents an appealing target for a live, noninvasive optical imaging of AD if disease pathology is manifested there. We identified retinal A? plaques in postmortem eyes from AD patients (n=8) and in suspected early stage cases (n=5), consistent with brain pathology and clinical reports; plaques were undetectable in age-matched non-AD individuals (n=5). In APP(SWE)/PS1(?E9) transgenic mice (AD-Tg; n=18) but not in non-Tg wt mice (n=10), retinal A? plaques were detected following systemic administration of curcumin, a safe plaque-labeling fluorochrome. Moreover, retinal plaques were detectable earlier than in the brain and accumulated with disease progression. An immune-based therapy effective in reducing brain plaques, significantly reduced retinal A? plaque burden in immunized versus non-immunized AD mice (n=4 mice per group). In live AD-Tg mice (n=24), systemic administration of curcumin allowed noninvasive optical imaging of retinal A? plaques in vivo with high resolution and specificity; plaques were undetectable in non-Tg wt mice (n=11). Our discovery of A? specific plaques in retinas from AD patients, and the ability to noninvasively detect individual retinal plaques in live AD mice establish the basis for developing high-resolution optical imaging for early AD diagnosis, prognosis assessment and response to therapies. PMID:20550967

Koronyo-Hamaoui, Maya; Koronyo, Yosef; Ljubimov, Alexander V; Miller, Carol A; Ko, Minhee K; Black, Keith L; Schwartz, Michal; Farkas, Daniel L



Non-calcified coronary atherosclerotic plaque characterization by dual energy computed tomography.  


Coronary heart disease (CHD) is the most prevalent cause of death worldwide. Atherosclerosis which is the condition of plaque buildup on the inside of the coronary artery wall is the main cause of CHD. Rupture of unstable atherosclerotic coronary plaque is known to be the cause of acute coronary syndrome. Vulnerability of atherosclerotic plaque has been related to a large lipid core covered by a fibrous cap. Non-invasive assessment of plaque characterization is necessary due to prognostic importance of early stage identification. The purpose of this study is to use the additional attenuation data provided by dual energy computed tomography (DECT) for plaque characterization. We propose to train supervised learners on pixel values recorded from DECT monochromatic X-ray and material basis pairs images, for more precise classification of fibrous and lipid plaques. The interaction of the pixel values from different image types is taken into consideration, as single pixel value might not be informative enough to separate fibrous from lipid. Organic phantom plaques scanned in a fabricated beating heart phantom were used as ground truth to train the learners. Our results show that support vector machines, artificial neural networks and random forests provide accurate results both on phantom and patient data. PMID:24808227

Yamak, Didem; Panse, Prasad; Pavlicek, William; Boltz, Thomas; Akay, Metin



A framework for the co-registration of hemodynamic forces and atherosclerotic plaque components  

PubMed Central

Local hemodynamic forces, such as wall shear stress, are thought to trigger cellular and molecular mechanisms that determine atherosclerotic plaque vulnerability to rupture. Magnetic resonance imaging (MRI) has emerged as a powerful tool to characterize human carotid atherosclerotic plaque composition and morphology, and to identify plaque features shown to be key determinants of plaque vulnerability. Image-based computational fluid dynamics (CFD) has allowed researchers to obtain time-resolved wall shear stress (WSS) information of atherosclerotic carotid arteries. A deeper understanding of the mechanisms of initiation and progression of atherosclerosis can be obtained through the comparison of WSS and plaque composition and morphology. To date, however, advance in knowledge has been limited greatly due to the lack of a reliable infrastructure to perform such analysis. The aim of this study is to establish a framework that will allow for the co-registration and analysis of the three-dimensional (3D) distribution ofWSS and plaque components and morphology. The use of this framework will lead to future studies targeted to determining the role of WSS in atherosclerotic plaque progression and vulnerability. PMID:23945133

Chiu, Bernard; Chen, Huijun; Chen, Yimin; Hatsukami, Thomas S.; Kerwin, William S.; Yuan, Chun



A feasibility study of carotid elastography for risk assessment of atherosclerotic plaques validated by magnetic resonance imaging  

NASA Astrophysics Data System (ADS)

Stroke is a leading cause of mortality worldwide. One of its main reasons is rupture of carotid atherosclerotic plaques. Conventional B-mode ultrasound images and Doppler/color flow measurements are mostly used to evaluate degree of stenosis, which underestimates plaque vulnerability. Alternatively, the correspondence between multi-contrast magnetic resonance imaging (MRI) features, plaque composition and histology has been well established. In this study, the feasibility of ultrasound carotid elastography in risk assessment of carotid atherosclerotic plaques is investigated. Preliminarily in-vivo results on a small number of human subjects are initially validated by multi-contrast, highresolution MRI, and it shows that maximum strain rate might be feasible to evaluate the plaque vulnerability.

Pan, Xiaochang; Huang, Lingyun; Huang, Manwei; Zhao, Xihai; He, Le; Yuan, Chun; Bai, Jing; Luo, Jianwen



Small Plaque Mutants of the Sindbis Virus.  

National Technical Information Service (NTIS)

In embryo cell cultures in gel medium infected with the Sindbis virus, two types of plaques appear: large (G) and small (p) plaques. The G plaques appear in 24 hours and grow until they attain a diameter of more than 20mm. The small plaques (p) appear aft...

C. Hannoun, J. Asso, P. Ardoin



Computational approaches for analyzing the mechanics of atherosclerotic plaques: a review.  


Vulnerable and stable atherosclerotic plaques are heterogeneous living materials with peculiar mechanical behaviors depending on geometry, composition, loading and boundary conditions. Computational approaches have the potential to characterize the three-dimensional stress/strain distributions in patient-specific diseased arteries of different types and sclerotic morphologies and to estimate the risk of plaque rupture which is the main trigger of acute cardiovascular events. This review article attempts to summarize a few finite element (FE) studies for different vessel types, and how these studies were performed focusing on the used stress measure, inclusion of residual stress, used imaging modality and material model. In addition to histology the most used imaging modalities are described, the most common nonlinear material models and the limited number of models for plaque rupture used for such studies are provided in more detail. A critical discussion on stress measures and threshold stress values for plaque rupture used within the FE studies emphasizes the need to develop a more location and tissue-specific threshold value, and a more appropriate failure criterion. With this addition future FE studies should also consider more advanced strain-energy functions which then fit better to location and tissue-specific experimental data. PMID:24491496

Holzapfel, Gerhard A; Mulvihill, John J; Cunnane, Eoghan M; Walsh, Michael T



Plaque Assay for Murine Norovirus  

PubMed Central

Murine norovirus (MNV) is the only member of the Norovirus genus that efficiently grows in tissue culture 1, 2. Cell lysis and cytopathic effect (CPE) are observed during MNV-1 infection of murine dendritic cells or macrophages 1. This property of MNV-1 can be used to quantify the number of infectious particles in a given sample by performing a plaque assay 1. The plaque assay relies on the ability of MNV-1 to lyse cells and to form holes in a confluent cell monolayer, which are called plaques 3. Multiple techniques can be used to detect viral infections in tissue culture, harvested tissue, clinical, and environmental samples, but not all measure the number of infectious particles (e.g. qRT-PCR). One way to quantify infectious viral particles is to perform a plaque assay 3, which will be described in detail below. A variation on the MNV plaque assay is the fluorescent focus assay, where MNV antigen is immunostained in cell monolayers 4. This assay can be faster, since viral antigen expression precedes plaque formation. It is also useful for titrating viruses unable to form plaques. However, the fluorescent focus assay requires additional resources beyond those of the plaque assay, such as antibodies and a microscope to count focus-forming units. Infectious MNV can also be quantified by determining the 50% Tissue Culture Infective Dose (TCID50) 3. This assay measures the amount of virus required to produce CPE in 50% of inoculated tissue culture cells by endpoint titration 5. However, its limit of detection is higher compared to a plaque assay 4. In this article, we describe a plaque assay protocol that can be used to effectively determine the number of infectious MNV particles present in biological or environmental samples 1, 4, 6. This method is based on the preparation of 10-fold serial dilutions of MNV-containing samples, which are used to inoculate a monolayer of permissive cells (RAW 264.7 murine macrophage cells). Virus is allowed to attach to the cell monolayer for a given period of time and then aspirated before covering cells with a mixture of agarose and cell culture media. The agar enables the spread of viral progeny to neighboring cells while limiting spread to distantly located cells. Consequently, infected cells are lysed and form holes in the monolayer known as plaques. Upon sufficient spread of virus, plaques become visible following staining of cells with dyes, like neutral red, methylene blue, or crystal violet. At low dilutions, each plaque originates from one infectious viral particle and its progeny, which spread to neighboring cells. Thus, counting the number of plaques allows one to calculate plaque-forming units (PFU) present in the undiluted sample 3. PMID:22951568

Gonzalez-Hernandez, Mariam B.; Bragazzi Cunha, Juliana; Wobus, Christiane E.



The rhythmic expression of clock genes attenuated in human plaque-derived vascular smooth muscle cells  

PubMed Central

Background Acute myocardial infarction and stroke are more likely to occur in the early morning. Circadian pacemakers are considered to be involved in the process. Many peripheral tissues and cells also contain clock systems. In this study, we examined whether the primary cultured human plaque-derived vascular smooth muscle cells (VSMCs) process circadian rhythmicity; furthermore, we investigated the expression difference of clock genes between normal human carotid VSMCs and human plaque-derived VSMCs. Methods Fifty-six human carotid plaques provided the atherosclerotic tissue, and 21 samples yielded viable cultured primary VSMCs. The normal carotid VSMCs were cultured from donors’ normal carotids. The mRNA levels of the target genes were measured by Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). Results After serum shock, both types of cells showed clear circadian expressions of Bmal1, Cry1, Cry2, Per1, Per2, Per3 and Rev-erb? mRNA; meanwhile the Clock mRNA show a rhythmic expression in plaque-derived SMCs but not in normal carotid VSMCs. The expression levels of these main clock genes were significantly attenuated in human plaque-derived VSMCs compared with normal human carotid VSMCs. The rhythm of Bmal1 mRNA in plaque-derived VSMCs was changed. Conclusion The present results demonstrate that the human plaque-derived VSMCs possess different circadian rhythmicity from that of normal carotid VSMCs. The rhythm changes of clock genes in plaque-derived VSMCs may be involved in the process of atherosclerosis and finally promote the rupture of plaque. PMID:24418196



Stress test evaluation of cobalt-enhanced nickel plaque electrodes  

NASA Astrophysics Data System (ADS)

The addition of cobalt to the surface of aerospace-quality sintered nickel plaque was observed to improve plate performance during a 5000 cycle stress test. A two-level, four-factor full factorial design matrix was established to compare the performance of cobalt-enhanced nickel plates with standard aerospace quality nickel plates during testing. The three other factors were loading level, current density during electrochemical impregnation and the concentration of KOH electrolyte. Regression analysis after 4000 cycles indicates that nickel plates fabricated from cobalt-enhanced plaque using a low current density during the electrochemical impregnation step provides the best performance during high rate charge/discharge applications.

Russell, Philip G.; Kuklinski, Jerry


Ruptured ulnar artery pseudoaneurysm  

Microsoft Academic Search

Ulnar artery aneurysms and pseudoaneurysms are rare lesions that usually occur distal to the wrist and cause symptoms as a result of embolization and not rupture. An elderly woman presented with acute rupture of an ulnar artery pseudoaneurysm proximal to the wrist, which caused severe neurologic compromise as a result of bleeding into Guyon's canal and the carpal tunnel. The

Luke S. Erdoes; William C. Brown



Possible earthquake rupture speeds  

NASA Astrophysics Data System (ADS)

Though mode II shear fractures (primarily strike slip earthquakes) can not only exceed the shear wave speed of the medium, but can even reach the compressional wave speed, steady-state calculations showed that speeds between the Rayleigh and shear wave speeds were not possible, thus defining a forbidden zone. For more than 30 years it was believed that this result in which the rupture jumps over the forbidden zone, also holds for 3-D ruptures, in which mode II and mode III (mainly dip-slip faulting) are mixed. Using unprecedentedly fine spatial and temporal grids, we show that even in the simple configuration of homogeneous fault properties and linear slip-weakening friction law, a realistic 3-D rupture which start from rest and accelerates to some higher velocity, actually does pass smoothly through this forbidden zone, but very fast. The energy flux from the rupture tip is always positive, even within the so-called forbidden zone, contrary to the 2-D case. Finally, our results show that the width of the cohesive zone initially decreases, then increases as the rupture exceeds the shear wave speed and finally again decreases as the rupture accelerates to a speed of ~90% of the compressional wave speed. Several movies illustrating the development of the ruptures will be shown. A. Bizzari and S. Das (2012). Possible earthquake rupture speeds, EPSL, submitted.

Das, S.; Bizzarri, A.



Non-invasive measurement of coronary plaque from coronary CT angiography and its clinical implications.  


Coronary CT angiography (CTA) is increasingly used worldwide for direct, non-invasive evaluation of the coronary arteries. Advances in computed tomography (CT) technology over the last decade have enabled such reliable imaging of the coronary arteries. Beyond arterial stenosis, coronary CTA also permits assessment of atherosclerotic plaque (including plaque burden) and coronary artery remodeling, previously only achievable through invasive means. It has been shown that coronary plaque volumes for non-calcified and mixed plaques and the arterial remodeling index, correlate closely with invasive intravascular ultrasound. Several studies have also shown a strong relationship of adverse plaque features imaged by coronary CTA with acute coronary syndrome, all-cause death, major adverse cardiovascular events and myocardial ischemia. The aim of this review is to summarize current methods for quantitative measurement of atherosclerotic plaque features from coronary CTA and to discuss their clinical implications. PMID:23984930

Dey, Damini; Schuhbaeck, Annika; Min, James K; Berman, Daniel S; Achenbach, Stephan



During atherosclerosis, the arterial wall gradually thickens to form an atherosclerotic plaque, resulting in the narrowing of the lumen of  

E-print Network

with atherosclerotic disease and its risk factors (discussed later). Studies of genetically modified mice are also condition arising from simple mendelian genetics is found to be associated with altered risk to the organ is reduced, most commonly affecting the heart and the brain. Plaques can abruptly rupture, causing

Cai, Long


High expression of genes for calcification-regulating proteins in human atherosclerotic plaques.  

PubMed Central

Calcification is common in atheromatous plaques and may contribute to plaque rupture and subsequent thrombosis. However, little is known about the mechanisms which regulate the calcification process. Using in situ hybridization and immunohistochemistry we show that two bone-associated proteins, osteopontin (OP) and matrix Gla protein (MGP), are highly expressed in human atheromatous plaques. High levels of OP mRNA and protein were found in association with necrotic lipid cores and areas of calcification. The predominant cell type in these areas was the macrophage-derived foam cell, although some smooth muscle cells could also be identified. MGP was expressed uniformly by smooth muscle cells in the normal media and at high levels in parts of the atheromatous intima. Highest levels of this matrix-associated protein were found in lipid-rich areas of the plaque. The pattern of expression of these two genes contrasted markedly with that of calponin and SM22 alpha, genes expressed predominantly by differentiated smooth muscle cells and whose expression was generally confined to the media of the vessel. The postulated function of OP and MGP as regulators of calcification in bone and the high levels and colocalization of both in atheromatous plaques suggest they have an important role in plaque pathogenesis and stability. Images PMID:8200973

Shanahan, C M; Cary, N R; Metcalfe, J C; Weissberg, P L



Identification of carotid plaque tissue properties using an experimental-numerical approach.  


A biomechanical stress analysis could help to identify carotid plaques that are vulnerable to rupture, and hence reduce the risk of thrombotic strokes. Mechanical stress predictions critically depend on the plaque's constitutive properties, and the present study introduces a concept to derive viscoelastic parameters through an experimental-numerical approach. Carotid plaques were harvested from two patients during carotid endarterectomy (CEA), and, in total, nine test specimens were investigated. A novel in-vitro mechanical testing protocol, which allows for dynamic testing, keeping the carotid plaque components together, was introduced. Macroscopic pictures overlaid by histological stains allowed for the segmentation of plaque tissues, in order to develop high-fidelity and low-fidelity Finite Element Method (FEM) models of the test specimens. The FEM models together with load-displacement data from the mechanical testing were used to extract constitutive parameters through inverse parameter estimation. The applied inverse parameter estimation runs in stages, first addressing the hyperelastic parameters then the viscoelastic ones. Load-displacement curves from the mechanical testing showed strain stiffening and viscoelasticity, as is expected for both normal and diseased carotid tissue. The estimated constitutive properties of plaque tissue were comparable to previously reported studies. Due to the highly non-linear elasticity of vascular tissue, the applied parameter estimation approach is, as with many similar approaches, sensitive to the initial guess of the parameters. PMID:23790614

Heiland, Vincent M; Forsell, Caroline; Roy, Joy; Hedin, Ulf; Gasser, T Christian



Molecular imaging of plaque vulnerability.  


Over the past decade, significant progress has been made in the development of novel imaging strategies focusing on the biology of the vessel wall for identification of vulnerable plaques. While the majority of these studies are still in the pre-clinical stage, few techniques (e.g., (18)F-FDG and (18)F-NaF PET imaging) have already been evaluated in clinical studies with promising results. Here, we will briefly review the pathobiology of atherosclerosis and discuss molecular imaging strategies that have been developed to target these events, with an emphasis on mechanisms that are associated with atherosclerotic plaque vulnerability. PMID:25124827

Tavakoli, Sina; Vashist, Aseem; Sadeghi, Mehran M



Surgical treatment of distal biceps rupture.  


Rupture of the distal biceps tendon accounts for 10% of all biceps brachii ruptures. Injuries typically occur in the dominant elbow of men aged 40 to 49 years during eccentric contraction of the biceps. Degenerative changes, decreased vascularity, and tendon impingement may precede rupture. Although nonsurgical management is an option, healthy, active persons with distal biceps tendon ruptures benefit from early surgical repair, gaining improved strength in forearm supination and, to a lesser degree, elbow flexion. Biomechanical studies have tested the strength and displacement of various repairs; the suspensory cortical button technique exhibits maximum peak load to failure in vitro, and suture anchor and interosseous screw techniques yield the least displacement. Surgical complications include sensory and motor neurapraxia, infection, and heterotopic ossification. Current trends in postoperative rehabilitation include an early return to motion and to activities of daily living. PMID:20190104

Sutton, Karen M; Dodds, Seth D; Ahmad, Christopher S; Sethi, Paul M



Carotid arterial plaque stress analysis using fluid-structure interactive simulation based on in-vivo magnetic resonance images of four patients.  


The rupture of atherosclerotic plaques is known to be associated with the stresses that act on or within the arterial wall. The extreme wall tensile stress (WTS) is usually recognized as a primary trigger for the rupture of vulnerable plaque. The present study used the in-vivo high-resolution multi-spectral magnetic resonance imaging (MRI) for carotid arterial plaque morphology reconstruction. Image segmentation of different plaque components was based on the multi-spectral MRI and co-registered with different sequences for the patient. Stress analysis was performed on totally four subjects with different plaque burden by fluid-structure interaction (FSI) simulations. Wall shear stress distributions are highly related to the degree of stenosis, while the level of its magnitude is much lower than the WTS in the fibrous cap. WTS is higher in the luminal wall and lower at the outer wall, with the lowest stress at the lipid region. Local stress concentrations are well confined in the thinner fibrous cap region, and usually locating in the plaque shoulder; the introduction of relative stress variation during a cycle in the fibrous cap can be a potential indicator for plaque fatigue process in the thin fibrous cap. According to stress analysis of the four subjects, a risk assessment in terms of mechanical factors could be made, which may be helpful in clinical practice. However, more subjects with patient specific analysis are desirable for plaque-stability study. PMID:19464011

Gao, Hao; Long, Quan; Graves, Martin; Gillard, Jonathan H; Li, Zhi-Yong



Raised Soluble P-Selectin Moderately Accelerates Atherosclerotic Plaque Progression  

PubMed Central

Soluble P-selectin (sP-selectin), a biomarker of inflammatory related pathologies including cardiovascular and peripheral vascular diseases, also has pro-atherosclerotic effects including the ability to increase leukocyte recruitment and modulate thrombotic responses in vivo. The current study explores its role in progressing atherosclerotic plaque disease. Apoe?/? mice placed on a high fat diet (HFD) were given daily injections of recombinant dimeric murine P-selectin (22.5 µg/kg/day) for 8 or 16 weeks. Saline or sE-selectin injections were used as negative controls. In order to assess the role of sP-selectin on atherothrombosis an experimental plaque remodelling murine model, with sm22?-hDTR Apoe?/? mice on a HFD in conjunction with delivery of diphtheria toxin to induce targeted vascular smooth muscle apoptosis, was used. These mice were similarly given daily injections of sP-selectin for 8 or 16 weeks. While plaque mass and aortic lipid content did not change with sP-selectin treatment in Apoe?/? or SM22?-hDTR Apoe?/? mice on HFD, increased plasma MCP-1 and a higher plaque CD45 content in Apoe?/? HFD mice was observed. As well, a significant shift towards a more unstable plaque phenotype in the SM22?-hDTR Apoe?/? HFD mice, with increased macrophage accumulation and lower collagen content, leading to a lower plaque stability index, was observed. These results demonstrate that chronically raised sP-selectin favours progression of an unstable atherosclerotic plaque phenotype. PMID:24846287

Andrews, Karen L.; Aprico, Andrea; Harris, Emma; Irvine, Jennifer C.; Jefferis, Ann-maree; Fang, Lu; Kanellakis, Peter; Bobik, Alex; Chin-Dusting, Jaye P. F.



Optical detection of structural changes in human carotid atherosclerotic plaque  

NASA Astrophysics Data System (ADS)

Background: Arterial bifurcations are commonly the sites of developing atherosclerotic plaque that lead to arterial occlusions and plaque rupture (myocardial infarctions and strokes). Laser induced fluorescence (LIF) spectroscopy provides an effective nondestructive method supplying spectral information on extracellular matrix (ECM) protein composition, specifically collagen and elastin. Purpose: To investigate regional differences in the ECM proteins -- collagen I, III and elastin in unstable plaque by analyzing data from laser-induced fluorescence spectroscopy of human carotid endarterectomy specimens. Methods: Gels of ECM protein extracts (elastin, collagen types I & III) were measured as reference spectra and internal thoracic artery segments (extra tissue from bypass surgery) were used as tissue controls. Arterial segments and the endarterectomy specimens (n=21) were cut into 5mm cross-sectional rings. Ten fluorescence spectra per sampling area were then recorded at 5 sites per ring with argon laser excitation (357nm) with a penetration depth of 200 ?m. Spectra were normalized to maximum intensity and analyzed using multiple regression analysis. Tissue rings were fixed in formalin (within 3 hours of surgery), sectioned and stained with H&E or Movat's Pentachrome for histological analysis. Spectroscopy data were correlated with immunohistology (staining for elastin, collagen types I, III and IV). Results: Quantitative fluorescence for the thoracic arteries revealed a dominant elastin component on the luminal side -- confirmed with immunohistology and known artery structure. Carotid endarterectomy specimens by comparison had a significant decrease in elastin signature and increased collagen type I and III. Arterial spectra were markedly different between the thoracic and carotid specimens. There was also a significant elevation (p<0.05) of collagen type I distal to the bifurcation compared to proximal tissue in the carotid specimens. Conclusion: Fluorescence spectroscopy is an effective method for evaluating ECM (collagen and elastin) associated with vascular remodeling despite the considerable variability in the plaque structure. Consistent regional differences were detected in the carotid specimens.

Korol, R. M.; Canham, P. B.; Finlay, H. M.; Hammond, R. R.; Quantz, M.; Ferguson, G. G.; Liu, L. Y.; Lucas, A. R.



Interstitial granulomatous dermatitis with plaques  

Microsoft Academic Search

Background: Interstitial granulomatous dermatitis is a histopathologic pattern with variable clinical appearance associated with autoimmune systemic diseases. The frequency of its different cutaneous expressions and its association with autoimmune diseases are not known. Objective: We describe the clinical, serologic, and histologic features in 17 patients with interstitial granulomatous dermatitis with a clinical presentation consisting of large erythematous plaques. Method: Skin

Carlo Tomasini; Mario Pippione



Human antimicrobial peptide LL37 is present in atherosclerotic plaques and induces death of vascular smooth muscle cells: a laboratory study  

Microsoft Academic Search

BACKGROUND: Death of smooth muscle cells in the atherosclerotic plaques makes the plaques more prone to rupture, which can initiate an acute ischemic event. The development of atherosclerosis includes the migration of immune cells e.g. monocytes\\/macrophages and T lymphocytes into the lesions. Immune cells can release antimicrobial peptides. One of these, human cathelicidin antimicrobial peptide hCAP-18, is cleaved by proteinase

Cristina D Ciornei; Hans Tapper; Anders Bjartell; Nils H Sternby; Mikael Bodelsson



Uterine rupture following termination of pregnancy in a scarred uterus.  


We present a series of two cases complicated by uterine rupture following termination of pregnancy (TOP) in the 1st and 2nd trimesters using misoprostol in women with caesarean section scar. Current literature and practise have also been reviewed on ruptured uterus in women with caesarean section scar undergoing TOP using misoprostol; the diagnosis of adherent placenta in the 1st and 2nd trimesters in women with previous caesarean uterine scar; and likely implications of a ruptured uterus. PMID:24456452

Bika, O; Huned, D; Jha, S; Selby, K



Reproducibility in Ultrasonic Characterization of Carotid Plaques  

Microsoft Academic Search

Background and Purpose: Echolucent carotid plaques compared with echogenic plaques could carry a significant risk of transient ischemic attacks and strokes, but the reproducibility of new ultrasonic methods has not yet been proved. The objective was to evaluate interobserver and intraobserver agreement in characterizing the carotid plaques studied by both B mode imaging and color Doppler imaging, which is the

J. M. de Bray; J. M. Baud; P. Delanoy; J. P. Camuzat; V. Dehans; J. Descamp-Le Chevoir; J. R. Launay; F. Luizy; Y. Sentou; P. Cales



Machine learning techniques as a helpful tool toward determination of plaque vulnerability.  


Atherosclerotic cardiovascular disease results in millions of sudden deaths annually, and coronary artery disease accounts for the majority of this toll. Plaque rupture plays main role in the majority of acute coronary syndromes. Rupture has been usually associated with stress concentrations, which are determined mainly by tissue properties and plaque geometry. The aim of this study is develop a tool, using machine learning techniques to assist the clinical professionals on decisions of the vulnerability of the atheroma plaque. In practice, the main drawbacks of 3-D finite element analysis to predict the vulnerability risk are the huge main memories required and the long computation times. Therefore, it is essential to use these methods which are faster and more efficient. This paper discusses two potential applications of computational technologies, artificial neural networks and support vector machines, used to assess the role of maximum principal stress in a coronary vessel with atheroma plaque as a function of the main geometrical features in order to quantify the vulnerability risk. PMID:22287230

Cilla, Myriam; Martínez, Javier; Peña, Estefanía; Martínez, Miguel Ángel



Differential association of visceral adipose tissue with coronary plaque characteristics in patients with and without diabetes mellitus  

PubMed Central

Background Excess visceral adipose tissue (VAT) is closely associated with the presence of coronary artery plaques that are vulnerable to rupture. Patients with diabetes mellitus (DM) have more VAT than patients without DM, but the extent to which VAT contributes to the characteristics of coronary plaques before and after the development of DM is not fully understood. Methods We retrospectively evaluated 456 patients (60% male, age 64?±?16 years) who were suspected to have cardiovascular disease and underwent 64-slice computed tomography angiography (CTA). Seventy-one (16%) patients had vulnerable plaques (CT density??1.05, and adjacent spotty areas of calcification). Results Patients were divided into tertiles according to the VAT area. There were stepwise increases in noncalcified and vulnerable plaques with increasing tertiles of VAT area in patients without DM, but not in patients with DM. Multivariate analysis showed that a larger VAT area was significantly associated with a higher risk of vulnerable plaque in patients without DM (odds ratio 3.17, 95% confidence interval 1.08–9.31, p?=?0.04), but not in patients with DM. Conclusions The VAT area is associated with the characteristics of coronary plaques on CTA in patients without DM, but not in patients with DM. VAT may be a significant cardiometabolic risk factor that is associated with plaque vulnerability before the development of DM. CTA findings may help to improve risk stratification in such patients. PMID:24624968



Plaque characteristics and arterial remodeling in coronary and peripheral arterial systems  

PubMed Central

Background Few studies have examined plaque characteristics among multiple arterial beds in vivo. The purpose of this study was to compare the plaque morphology and arterial remodeling between coronary and peripheral arteries using gray-scale and radiofrequency intravascular ultrasound (IVUS) at clinical presentation. Methods and Results IVUS imaging was performed in 68 patients with coronary and 93 with peripheral artery lesions (29 carotid, 50 renal, and 14 iliac arteries). Plaques were classified as fibroatheroma (VH-FA) (further subclassified as thin-capped [VH-TCFA] and thick-capped [VH-ThCFA]), fibrocalcific plaque (VH-FC) and pathological intimal thickening (VH-PIT). Plaque rupture (13% of coronary, 7% of carotid, 6% of renal, and 7% of iliac arteries; P=NS) and VHTCFA (37% of coronary, 24% of carotid, 16% of renal, and 7% of iliac arteries; p=0.02) were observed in all arteries. Compared with coronary arteries, VH-FA was less frequently observed in renal (p<0.001) and iliac arteries (p<0.006). Lesions with positive remodeling demonstrated more characteristics of VH-FA in coronary (84% vs. 25%, p<0.001), carotid (72% vs. 20%, p=0.001), and renal arteries (42% vs. 4%, p=0.001) compared with those with intermediate/negative remodeling. There was positive relationship between RI and percent necrotic area in all four arteries. Conclusions Atherosclerotic plaque phenotypes were heterogeneous among four different arteries; renal and iliac arteries had more stable phenotypes compared with coronary artery. In contrast, the associations of remodeling pattern with plaque phenotype and composition were similar among the various arterial beds. PMID:22721702

Matsuo, Yoshiki; Takumi, Takuro; Mathew, Verghese; Chung, Woo-Young; Barsness, Gregory W.; Rihal, Charanjit S.; Gulati, Rajiv; McCue, Eric T.; Holmes, David R; Eeckhout, Eric; Lennon, Ryan J.; Lerman, Lilach O.; Lerman, Amir



Towards coronary plaque imaging using simultaneous PET-MR: a simulation study  

NASA Astrophysics Data System (ADS)

Coronary atherosclerotic plaque rupture is the main cause of myocardial infarction and the leading killer in the US. Inflammation is a known bio-marker of plaque vulnerability and can be assessed non-invasively using fluorodeoxyglucose-positron emission tomography imaging (FDG-PET). However, cardiac and respiratory motion of the heart makes PET detection of coronary plaque very challenging. Fat surrounding coronary arteries allows the use of MRI to track plaque motion during simultaneous PET-MR examination. In this study, we proposed and assessed the performance of a fat-MR based coronary motion correction technique for improved FDG-PET coronary plaque imaging in simultaneous PET-MR. The proposed methods were evaluated in a realistic four-dimensional PET-MR simulation study obtained by combining patient water-fat separated MRI and XCAT anthropomorphic phantom. Five small lesions were digitally inserted inside the patients coronary vessels to mimic coronary atherosclerotic plaques. The heart of the XCAT phantom was digitally replaced with the patient's heart. Motion-dependent activity distributions, attenuation maps, and fat-MR volumes of the heart, were generated using the XCAT cardiac and respiratory motion fields. A full Monte Carlo simulation using Siemens mMR's geometry was performed for each motion phase. Cardiac/respiratory motion fields were estimated using non-rigid registration of the transformed fat-MR volumes and incorporated directly into the system matrix of PET reconstruction along with motion-dependent attenuation maps. The proposed motion correction method was compared to conventional PET reconstruction techniques such as no motion correction, cardiac gating, and dual cardiac-respiratory gating. Compared to uncorrected reconstructions, fat-MR based motion compensation yielded an average improvement of plaque-to-background contrast of 29.6%, 43.7%, 57.2%, and 70.6% for true plaque-to-blood ratios of 10, 15, 20 and 25:1, respectively. Channelized Hotelling observer (CHO) signal-to-noise ratio (SNR) was used to quantify plaque detectability. CHO-SNR improvement ranged from 105% to 128% for fat-MR-based motion correction as compared to no motion correction. Likewise, CHO-SNR improvement ranged from 348% to 396% as compared to both cardiac and dual cardiac-respiratory gating approaches. Based on this study, our approach, a fat-MR based motion correction for coronary plaque PET imaging using simultaneous PET-MR, offers great potential for clinical practice. The ultimate performance and limitation of our approach, however, must be fully evaluated in patient studies.

Petibon, Y.; El Fakhri, G.; Nezafat, R.; Johnson, N.; Brady, T.; Ouyang, J.



Towards coronary plaque imaging using simultaneous PET-MR: a simulation study.  


Coronary atherosclerotic plaque rupture is the main cause of myocardial infarction and the leading killer in the US. Inflammation is a known bio-marker of plaque vulnerability and can be assessed non-invasively using fluorodeoxyglucose-positron emission tomography imaging (FDG-PET). However, cardiac and respiratory motion of the heart makes PET detection of coronary plaque very challenging. Fat surrounding coronary arteries allows the use of MRI to track plaque motion during simultaneous PET-MR examination. In this study, we proposed and assessed the performance of a fat-MR based coronary motion correction technique for improved FDG-PET coronary plaque imaging in simultaneous PET-MR. The proposed methods were evaluated in a realistic four-dimensional PET-MR simulation study obtained by combining patient water-fat separated MRI and XCAT anthropomorphic phantom. Five small lesions were digitally inserted inside the patients coronary vessels to mimic coronary atherosclerotic plaques. The heart of the XCAT phantom was digitally replaced with the patient's heart. Motion-dependent activity distributions, attenuation maps, and fat-MR volumes of the heart, were generated using the XCAT cardiac and respiratory motion fields. A full Monte Carlo simulation using Siemens mMR's geometry was performed for each motion phase. Cardiac/respiratory motion fields were estimated using non-rigid registration of the transformed fat-MR volumes and incorporated directly into the system matrix of PET reconstruction along with motion-dependent attenuation maps. The proposed motion correction method was compared to conventional PET reconstruction techniques such as no motion correction, cardiac gating, and dual cardiac-respiratory gating. Compared to uncorrected reconstructions, fat-MR based motion compensation yielded an average improvement of plaque-to-background contrast of 29.6%, 43.7%, 57.2%, and 70.6% for true plaque-to-blood ratios of 10, 15, 20 and 25:1, respectively. Channelized Hotelling observer (CHO) signal-to-noise ratio (SNR) was used to quantify plaque detectability. CHO-SNR improvement ranged from 105% to 128% for fat-MR-based motion correction as compared to no motion correction. Likewise, CHO-SNR improvement ranged from 348% to 396% as compared to both cardiac and dual cardiac-respiratory gating approaches. Based on this study, our approach, a fat-MR based motion correction for coronary plaque PET imaging using simultaneous PET-MR, offers great potential for clinical practice. The ultimate performance and limitation of our approach, however, must be fully evaluated in patient studies. PMID:24556608

Petibon, Y; El Fakhri, G; Nezafat, R; Johnson, N; Brady, T; Ouyang, J



Anterior Cruciate Ligament Rupture and Osteoarthritis Progression  

PubMed Central

Anterior Cruciate Ligament (ACL) rupture is a common sporting injury that frequently affects young, athletic patients. Apart from the functional problems of instability, patients with ACL deficient knees also develop osteoarthritis. Although this is frequently cited as an indication for ACL reconstruction, the relationship between ACL rupture, reconstruction and the instigation and progression of articular cartilage degenerative change is controversial. The purpose of this paper is to review the published literature with regards ACL rupture and the multifactorial causes for osteoarthritis progression, and whether or not this is slowed or stopped by ACL reconstruction. There is no evidence in the published literature to support the view that ACL reconstruction prevents osteoarthritis, although it may prevent further meniscal damage. It must be recognised that this conclusion is based on the current literature which has substantial methodological limitations. PMID:22896777

Wong, James Min-Leong; Khan, Tanvir; Jayadev, Chethan S; Khan, Wasim; Johnstone, David



Fluoride in Dental Plaque and its Effects  

Microsoft Academic Search

Total plaque fluoride is in the range 5-10 mg\\/kg (ppm) on a wet-weight basis. The variability of literature data on plaque fluoride is partly ascribed to analytical problems, many assays being close to or below the concentration detection limit of the fluoride electrode. A change in classification of plaque fluoride compartments is necessary, since recent work indicates that there are

A. Tatevossian



Bipolar infrapatellar tendon rupture.  


Traumatic patella alta in children occurs either distal to the patellar tendon as a tibial tubercle apophyseal fracture or proximally as an osteochondral sleeve fracture of the inferior patellar pole. Acute surgical exploration in a pediatric case of a knee extensor mechanism rupture revealed both proximal and distal (bipolar) patellar tendon pathology. PMID:7790483

Berg, E E



Imaging gate oxide ruptures  

Microsoft Academic Search

As minimum feature sizes are reduced in MOS silicon devices, dielectric breakdown continues to pose a formidable challenge. A more complete understanding of the failure mechanism which induces oxide rupture has become an absolute necessity in order to meet the advancing yield and reliability requirements of today's complex integrated structures. This paper will present an interesting insight into the nature

Horacio Mendez; Steve Morris; Sudhindra Tatti; Nicholas Dickson; Ronald E. Pyle



The relevance of Randall's plaques  

PubMed Central

The pathophysiology of nephrolithiasis is not fully understood. The pioneering work of Alexander Randall in the 1940s sought to clarify our understanding of stone formation. This review traces the inception of the theory of Randall's plaques and the refinement of the hypothesis in the early days of kidney stone research. It then reviews the contemporary findings utilizing sophisticated investigative techniques that shed additional light on the pathophysiology and redefine the seminal findings of Dr. Randall that were made 70 years ago. PMID:24497683

Strakosha, Ruth; Monga, Manoj; Wong, Michael Y. C.



Fault branching and rupture directivity  

Microsoft Academic Search

Could the directivity of a complex earthquake be inferred from the ruptured fault branches it created? Typically, branches develop in forward orientation, making acute angles relative to the propagation direction. Direct backward branching of the same style as the main rupture (e.g., both right lateral) is disallowed by the stress field at the rupture front. Here we propose another mechanism

Sonia Fliss; Harsha S. Bhat; Renata Dmowska; James R. Rice



Inhibition of a4 Integrin and ICAM-1 Markedly Attenuate Macrophage Homing to Atherosclerotic Plaques in ApoE-Deficient Mice  

Microsoft Academic Search

Background—Monocytes\\/macrophages play a central role in many stages of development of atherosclerotic plaques, including the conversion to an unstable morphology with rupture and fissuring. A better understanding of the mechanism of attachment of monocytes to activated endothelial cells would prove useful in developing strategies aimed at blocking this initial step. Here we describe a novel in vivo model that directly

Shilpesh S. Patel; Ram Thiagarajan; James T. Willerson; Edward T. H. Yeh


Impact of Wall Shear Stress and Pressure Variation on the Stability of Atherosclerotic Plaque  

NASA Astrophysics Data System (ADS)

Rupture of vulnerable atheromatous plaque in the carotid and coronary arteries often leads to stroke and heart attack respectively. The mechanism of blood flow and plaque rupture in stenotic arteries is still not fully understood. A three dimensional rigid wall model was solved under steady and unsteady conditions assuming a time-varying inlet velocity profile to investigate the relative importance of axial forces and pressure drops in arteries with asymmetric stenosis. Flow-structure interactions were investigated for the same geometry and the results were compared with those retrieved with the corresponding one dimensional models. The Navier-Stokes equations were used as the governing equations for the fluid. The tube wall was assumed linearly elastic, homogeneous isotropic. The analysis showed that wall shear stress is small (less than 3.5%) with respect to pressure drop throughout the cycle even for severe stenosis. On the contrary, the three dimensional behavior of velocity, pressure and wall shear stress is in general very different from that predicted by one dimensional models. This suggests that the primary source of mistakes in one dimensional studies comes from neglecting the three dimensional geometry of the plaque. Neglecting axial forces only involves minor errors.

Taviani, V.; Li, Z. Y.; Sutcliffe, M.; Gillard, J.


Iron plaque formation on seagrasses: Why not?  

Microsoft Academic Search

Iron (Fe) plaque formation is a well known phenomenon in wetland, freshwater and salt marsh species; however there are no reports about Fe plaque occurrence in seagrasses. Here we review the main factors regulating Fe deposition on the roots and rhizomes of plants from reduced sediments\\/soils, and discuss these factors in relation to marine environment. Moreover, we present some early

K atrina Povidisa; Marianne Holmer



Receptor-targeted Iron Oxide Nanoparticles for Molecular MR Imaging of Inflamed Atherosclerotic Plaques  

PubMed Central

In a number of literature reports iron oxide nanoparticles have been investigated for use in imaging atherosclerotic plaques and found to accumulate in plaques via uptake by macrophages, which are critical in the process of atheroma initiation, propagation, and rupture. However, the uptake of these agents is nonspecific, thus the labeling efficiency for plaques in vivo is not ideal. We have developed targeted agents to improve the efficiency for labeling macrophage-laden plaques. These probes are based on iron oxide nanoparticles coated with dextran sulfate, a ligand of macrophage scavenger receptor type A (SR-A). We have sulfated dextran-coated iron oxide nanoparticles (DIO) with sulfur trioxide, thereby targeting our nanoparticle imaging agents to SR-A. The sulfated DIO (SDIO) remained mono-dispersed and had an average hydrodynamic diameter of 62 nm, an r1 relaxivity of 18.1 mM?1s?1, and an r2 relaxivity of 95.8 mM?1s?1 (37 °C, 1.4 T). Cell studies confirmed that these nanoparticles were nontoxic and specifically targeted to macrophages. In vivo MRI after intravenous injection of the contrast agent into an atherosclerotic mouse injury model showed substantial signal loss on the injured carotid at 4 and 24 hours post-injection of SDIO. No discernable signal decrease was seen at the control carotid and only mild signal loss was observed for the injured carotid post-injection of non-sulfated DIO, indicating preferential uptake of the SDIO particles at the site of atherosclerotic plaque. These results indicate that SDIO can facilitate MRI detection and diagnosis of vulnerable plaques in atherosclerosis. PMID:21742374

Tu, Chuqiao; Ng, Thomas S.C.; Sohi, Hargun; Palko, Heather; House, Adrian; Jacobs, Russell E.; Louie, Angelique Y.



Uptake of 68gallium in atherosclerotic plaques in LDLR-/-ApoB100/100 mice  

PubMed Central

Background Atherosclerosis is a chronic inflammatory disease of artery wall characterized by infiltration of monocytes into subendothelial space and their differentiation into macrophages. Since rupture-prone plaques commonly contain high amounts of activated macrophages, imaging of the macrophage content may provide a useful tool for the evaluation of plaque vulnerability. The purpose of this study was to explore the uptake of 68gallium (68Ga) in atherosclerotic plaques in mice. Methods Uptake of ionic 68Ga was investigated in atherosclerotic LDLR-/-ApoB100/100 and C57BL/6N control mice at 3 h after injection. The ex vivo biodistribution of the 68Ga was assessed and autoradiography of aortic cryosections was defined. In vivo imaging of 68Ga was performed using a small animal positron emission tomography PET/CT scanner. Results Our results revealed that the uptake of 68Ga-radioactivity was higher in atherosclerotic plaques than in healthy vessel wall (ratio 1.8 ± 0.2, p = 0.0002) and adventitia (ratio 1.3 ± 0.2, p = 0.0011). The autoradiography signal co-localized with macrophages prominently as demonstrated by Mac-3 staining. In both mice strains, the highest level of radioactivity was found in the blood. Conclusions We observed a moderate but significantly elevated 68Ga-radioactivity uptake in the aortic plaques of atherosclerotic mice, especially at the sites rich in macrophages. While the uptake of 68Ga was promising in this animal model, the slow blood clearance may limit the usability of 68Ga as a PET tracer for clinical imaging of atherosclerotic plaques. PMID:22214258



Iatrogenic tracheobronchial rupture  

PubMed Central

Abstract Iatrogenic tracheobronchial ruptures most frequently occur during tracheal intubation, but they can also be produced during tracheobronchial endoscopy or thoracic surgery. The clinical presentation can be brutal, with respiratory failure, cervical emphysema, pneumothorax and hemoptysis. There are also less symptomatic presentations. The diagnosis is confirmed by bronchoscopy. The therapeutic approach can be differentiated, surgical or conservative, although the criteria are not universally accepted. This article aims to review the indications and therapeutic options. PMID:25408752

Paraschiv, M



Advanced Techniques for MRI of Atherosclerotic Plaque  

PubMed Central

This review examines the state of the art in vessel wall imaging by MRI with an emphasis on the biomechanical assessment of atherosclerotic plaque. Three areas of advanced techniques are discussed. First, alternative contrast mechanisms, including susceptibility, magnetization transfer, diffusion and perfusion, are presented in regards to how they facilitate accurate determination of plaque constituents underlying biomechanics. Second, imaging technologies, including hardware and sequences, are reviewed in regards to how they provide the resolution and SNR necessary for determining plaque structure. Finally, techniques for combining MRI data into an overall assessment of plaque biomechanical properties, including wall shear stress and internal plaque strain, are presented. The paper closes with a discussion of the extent to which these techniques have been applied to different arteries commonly targeted by vessel wall MRI. PMID:20805732

Kerwin, William S.; Canton, Gador



Ni-Co alloy plaque for cathode of Ni-Cd battery  

NASA Astrophysics Data System (ADS)

The present invention relates generally to Ni-Cd batteries, and, in particular, relates to the plaque material attached to the cathode. Because of the wide use of nickel-cadmium batteries, the corrosion rates of nickel and nickel-cobalt alloys are of interest to nickel-cadmium battery electrochemical theory and its technology. The plaque material of the cathode consists of a Ni-Co alloy in solid solution wherein the cobalt is by weight percent one to ten percent of the alloy. Conventional methods of applying the plaque material to the nickel core may be used. It is therefore an object of the present invention to provide an improved cathode for a nickel-cadmium battery wherein the nickel corrosion is substantially lessened in the plaque material. One process of making the plaque uses a nickel powder slurry that is applied to a nickel-plated steel core. This is then sintered at a high temperature which results in a very porous structure and an welding of the nickel grains to the core. This plaque is then soaked in appropriate salts to make either a positive or a negative plate; nickel salts make a positive plate and a cadmium salts a negative plate, for example. After impregnation, the plaque is placed in an electrolyte and an electric current is passed therethrough to convert the salts to their final form. In the nickel-cadmium cell, nickel hydroxide is the active material in the positive plate.

Lander, J. J.



Modeling rupture segmentations on the Cascadia megathrust  

NASA Astrophysics Data System (ADS)

The Cascadia subduction zone has produced a series of large to great earthquakes, most recently in 1700 AD. Paleoseismological studies of submarine turbidites suggest a significant difference in recurrence interval between Northern (~500 year) and Southern (~200-300 year) Cascadia. Whether future large ruptures are segmented is very important for estimating hazard in Pacific Northwest, but remains enigmatic from the interpretations of current locking maps. Our approach is to develop rupture scenarios of Cascadia earthquakes by performing numerical simulations using the finite element software, PyLith. Based on the USGS plate interface model of Cascadia, we have constructed a realistic three-dimensional subduction fault model that stretches from Northern California to Central Vancouver Island. We have performed a number of dynamic rupture simulations using a set of artificial friction parameters and uniform stress distributions on the fault governed by a slip-weakening friction law. Preliminary results show that ruptures have initiated from the nucleation zone with higher shear stress than the ambient fault and have propagated on the realistic three-dimensional fault surface. The increase of dip angle with depth has little effect on the rupture propagation because that is governed mostly by the fault strength. The along-strike bend of the fault beneath Washington state and Vancouver Island has not impeded the rupture propagation given the uniform fault strength. To estimate the possible rupture segmentation, we have converted a slip-deficit rate model derived from GPS data into stress change distributions on the fault assuming the entire slip deficit would be released in the next great earthquake. We are also constructing another initial stress map derived from tidal and leveling data, which shows a significant difference in the locking depth beneath Central Oregon. The other important variable, the spatial variation of frictional parameters, however, has to be determined under certain assumptions. We assume the critical distance, Dc, is proportional to the final slip, thus will be obtained from the slip deficit distribution. By combining the estimated stresses and Dc for the slip-weakening relation, we will investigate how the different interseismic locking profiles could influence possible segmentation for future ruptures on the Cascadia megathrust. This work is supported by FM Global.

Yang, H.; Liu, Y.; McGuire, J. J.



Update on the Pathophysiological Role of Intracellular Signaling Pathways in Atherosclerotic Plaques and Ischemic Myocardium  

PubMed Central

Acute atherosclerotic complications, such as myocardial infarction, are often provoked by the rupture of an atherosclerotic plaque and the subsequent thrombotic occlusion of the arterial lumen, which interrupts the blood flow and renders ischemic the downstream peripheral tissue. Several inflammatory mediators (including cytokines, chemokines and matrix metalloproteases) have been shown to orchestrate common pathophysiological mechanisms regulating both plaque vulnerability and myocardial injury. In particular, the selective activation of certain protective intracellular signaling pathways might represent a promising target to reduce the dramatic consequences of an ischemic cardiac event. In the present review we will update evidence on the active role of intracellular kinase cascades (such as mitogen-activated protein kinases [MAPKs], Akt, Janus kinase [JAK]-signal transducer and activator of transcription [STAT]) to reduce the global patient vulnerability for acute myocardial infarction. PMID:22754427

Montecucco, Fabrizio; Braunersreuther, Vincent; Viviani, Giorgio Luciano; Lenglet, Sebastien; Mach, Francois



The prevention and regression of atherosclerotic plaques: emerging treatments.  


Occlusive vascular diseases, such as sudden coronary syndromes, stroke, and peripheral arterial disease, are a huge burden on the health care systems of developed and developing countries. Tremendous advances have been made over the last few decades in the diagnosis and treatment of atherosclerotic diseases. Intravascular ultrasound has been able to provide detailed information of plaque anatomy and has been used in several studies to assess outcomes. The presence of atherosclerosis disrupts the normal protective mechanism provided by the endothelium and this mechanism has been implicated in the pathophysiology of coronary artery disease and stroke. Efforts are being put into the prevention of atherosclerosis, which has been shown to begin in childhood. This paper reviews the pathophysiology of atherosclerosis and discusses the current options available for the prevention and reversal of plaque formation. PMID:23049260

Kalanuria, Atul Ashok; Nyquist, Paul; Ling, Geoffrey



Retinal arterial plaques in acquired immunodeficiency syndrome  

PubMed Central

The authors report the unusual observation discrete plaque like excrescencies along the retinal arterial wall in a young patient with acquired immunodeficiency syndrome. Though bilateral, in the right eye there was severe arteriolar narrowing and so these plaques were less identifiable. Fluorescein angiography did not reveal any arteriolar occlusion or areas of capillary occlusion in both eyes. There were no other signs of HIV associated microangiopathy and the patient did not have any concurrent cardiovascular or hematological abnormality. The cause of these plaques remains unexplained and we conjecture that they could represent macro immune-complex deposition along the arteriolar walls. PMID:24765430

Venkatesh, Pradeep; Pathak, Harish; Garg, Satpal



Slow rupture of frictional interfaces  

NASA Astrophysics Data System (ADS)

The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not completely understood. We show that slow rupture is an intrinsic and robust property of simple non-monotonic rate-and-state friction laws. It is associated with a new velocity scale cmin, determined by the friction law, below which steady state rupture cannot propagate. We further show that rupture can occur in a continuum of states, spanning a wide range of velocities from cmin to elastic wave-speeds, and predict different properties for slow rupture and ordinary fast rupture. Our results are qualitatively consistent with recent high-resolution laboratory experiments and may provide a theoretical framework for understanding slow rupture phenomena along frictional interfaces.

Bar Sinai, Yohai; Brener, Efim A.; Bouchbinder, Eran



Carotid plaque characterization using CT and MRI scans for synergistic image analysis  

NASA Astrophysics Data System (ADS)

Noninvasive determination of plaque vulnerability has been a holy grail of medical imaging. Despite advances in tomographic technologies , there is currently no effective way to identify vulnerable atherosclerotic plaques with high sensitivity and specificity. Computed tomography (CT) and magnetic resonance imaging (MRI) are widely used, but neither provides sufficient information of plaque properties. Thus, we are motivated to combine CT and MRI imaging to determine if the composite information can better reflect the histological determination of plaque vulnerability. Two human endarterectomy specimens (1 symptomatic carotid and 1 stable femoral) were imaged using Scanco Medical Viva CT40 and Bruker Pharmascan 16cm 7T Horizontal MRI / MRS systems. ?CT scans were done at 55 kVp and tube current of 70 mA. Samples underwent RARE-VTR and MSME pulse sequences to measure T1, T2 values, and proton density. The specimens were processed for histology and scored for vulnerability using the American Heart Association criteria. Single modality-based analyses were performed through segmentation of key imaging biomarkers (i.e. calcification and lumen), image registration, measurement of fibrous capsule, and multi-component T1 and T2 decay modeling. Feature differences were analyzed between the unstable and stable controls, symptomatic carotid and femoral plaque, respectively. By building on the techniques used in this study, synergistic CT+MRI analysis may provide a promising solution for plaque characterization in vivo.

Getzin, Matthew; Xu, Yiqin; Rao, Arhant; Madi, Saaussan; Bahadur, Ali; Lennartz, Michelle R.; Wang, Ge



A special type of senile plaque, possibly an initial stage  

Microsoft Academic Search

It is customary to distinguish “primitive”, “classic” and “compact” (“burned out”) senile plaques in Alzheimer's disease and senile dementia of the Alzheimer type (SDAT). Primitive plaques are characterized by altered neurites without accumulation of amyloid, classic plaques by an amyloid core surrounded by altered neurites and compact plaques by amyloid without pathological neurites. Here we describe a further type of

A. Probst; H. Brunnschweiler; C. Lautenschlager; J. Ulrich



Historical Plaque at Marshall Space Flight Center  

NASA Technical Reports Server (NTRS)

This plaque, displayed on the grounds of Marshall Space Flight Center in Huntsville, Alabama, commemorates the Redstone Test Stand as an Alabama Historic Civil Engineering Landmark. The site was desinated as such in 1979.



Antibody-Labeled Liposomes for CT Imaging of Atherosclerotic Plaques  

PubMed Central

We evaluated the specific binding of anti-intercellular adhesion molecule 1 (ICAM-1) conjugated liposomes (immunoliposomes, or ILs) to activated human coronary artery endothelial cells (HCAEC) with the purpose of designing a computed tomographic imaging agent for early detection of atherosclerotic plaques. Covalent attachment of anti-ICAM-1 monoclonal antibodies to pre-formed liposomes stabilized with polyethylene glycol yielded ILs, with a coupling efficiency of the ICAM-1 to the liposomes of 10% to 24%. The anti-ICAM-1–labeled ILs had an average diameter of 136 nm as determined by dynamic light-scattering and cryogenic electron microscopy. The ILs' encapsulation of 5-[N-acetyl-(2,3-dihydroxypropyl)-amino)-N, N?-bis(2,3-dihydroxypropyl)-2,4,6-triiodo-benzene-1,3-dicarboxamide (iohexol) was determined to be 18% to 19% by a dialysis technique coupled with ultraviolet detection of free iohexol. This encapsulation corresponded to 30 to 38 mg iodine per mL IL solution, and the ILs exhibited 91% to 98.5% iohexol retention at room temperature and under physiologic conditions. The specific binding of the ILs to cultured, activated HCAEC was measured using flow cytometry, enzyme-linked immunosorbent assays, and fluorescence microscopy. The immunosorbent assays demonstrated the specificity of binding of anti-ICAM-1 to ICAM-1 compared with control studies using nonspecific immunoglobulin G-labeled ILs. Flow cytometry and fluorescence microscopy experiments demonstrated the expression of ICAM-1 on the surface of activated HCAEC. Therefore, our iohexol-filled ILs demonstrated potential for implementation in computed tomographic angiography to noninvasively detect atherosclerotic plaques that are prone to rupture. PMID:19876414

Danila, Delia; Partha, Ranga; Elrod, Don B.; Lackey, Melinda; Casscells, S. Ward; Conyers, Jodie L.



Detection of High-Risk Atherosclerotic Plaque  

PubMed Central

The leading cause of major morbidity and mortality in most countries around the world is atherosclerotic cardiovascular disease, most commonly caused by thrombotic occlusion of a high-risk coronary plaque resulting in myocardial infarction or cardiac death, or embolization from a high-risk carotid plaque resulting in stroke. The lesions prone to result in such clinical events are termed vulnerable or high-risk plaques, and their identification may lead to the development of pharmacological and mechanical intervention strategies to prevent such events. Autopsy studies from patients dying of acute myocardial infarction or sudden death have shown that such events typically arise from specific types of atherosclerotic plaques, most commonly the thin-cap fibroatheroma. However, the search in human beings for vulnerable plaques before their becoming symptomatic has been elusive. Recently, the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study demonstrated that coronary plaques that are likely to cause future cardiac events, regardless of angiographic severity, are characterized by large plaque burden and small lumen area and/or are thin-cap fibroatheromas verified by radiofrequency intravascular ultrasound imaging. This study opened the door to identifying additional invasive and noninvasive imaging modalities that may improve detection of high-risk atherosclerotic lesions and patients. Beyond classic risk factors, novel biomarkers and genetic profiling may identify those patients in whom noninvasive imaging for vulnerable plaque screening, followed by invasive imaging for risk confirmation is warranted, and in whom future pharmacological and/or device-based focal or regional therapies may be applied to improve long-term prognosis. PMID:22974808

Fleg, Jerome L.; Stone, Gregg W.; Fayad, Zahi A.; Granada, Juan F.; Hatsukami, Thomas S.; Kolodgie, Frank D.; Ohayon, Jacques; Pettigrew, Roderic; Sabatine, Marc S.; Tearney, Guillermo; Waxman, Sergio; Domanski, Michael J.; Srinivas, Pothur R.; Narula, Jagat



Low Density Lipoprotein-Cholesterol/High Density Lipoprotein-Cholesterol Ratio Predicts Plaque Vulnerability in Patients With Stable Angina  

PubMed Central

Background and Objectives The relationship between lipid profile and coronary plaque tissue characteristics in patients with stable angina pectoris (SAP) is unclear. The aim of this study was to evaluate the relationship between tissue characteristics and lipid profile and predictors of unstable plaques (UPs) in patients with SAP by virtual histology intravascular ultrasonography (VH-IVUS). Subjects and Methods VH-IVUS was performed for target lesions in patients with SAP (61.7±9.2 years, 174 males, n=266) at the time of coronary angiography. UPs are characterized by thin-cap fibroatheroma, ruptured plaque, or remaining thrombus with VH-IVUS. Results The present study showed that 34 SAP patients had UPs (61.6±9.2 years, 24 males, 12.8%). The percentage of plaque area in the minimum luminal area in high low density lipoprotein-cholesterol (LDL-C)/high density lipoprotein-cholesterol (HDL-C) ratio patients was significantly higher than in low LDL-C/HDL-C ratio patients (72.7±9.5% vs. 69.9±9.3%, p=0.035). An LDL-C/HDL-C ratio >2.0 was an independent predictor for UPs in SAP patients (odds ratio 5.252, 95% confidence interval 1.132-24.372, p=0.034). Conclusion An elevated LDL-C/HDL-C ratio is a positive predictor for coronary plaque vulnerability in patients with SAP. PMID:22563337

Kim, Jeong Hun; Hong, Young Joon; Lee, Ki Hong; Kim, In Soo; Choi, Yun Ha; Lee, Min Goo; Park, Keun-Ho; Sim, Doo Sun; Kim, Ju Han; Ahn, Youngkeun; Cho, Jeong Gwan; Park, Jong Chun; Kang, Jung Chaee



Studies of the Rickettsial Plaque Assay Technique  

PubMed Central

A plaque assay system for pathogenic rickettsiae, which utilizes primary chick embryo tissue cultures, is described. It proved to be a highly reproducible measure of infectiousness for Rickettsia rickettsi and R. typhi, which were employed in most studies; as well as for R. canada, R. prowazeki, R. sibirica, R. akari, R. conori, and Coxiella burneti. Plaque-forming units (PFU) were compared to direct rickettsial counts and to 50% infectious dose (ID50) values for embryonated eggs, mice, and guinea pigs. Plaque size, appearance, and number were influenced by diluent, incubation temperature after nutrient overlay, centrifugation of inoculated tissue cultures, and number of host cells planted initially in each flask. The most critical factors in plaque formation were diluent used in making rickettsial suspensions and incubation temperature (32 C) after nutrient overlay. Brain Heart Infusion was the only diluent capable of preventing significant delay in plaque formation and decreases in PFU and mouse ID50. Plaque formation was unaffected by genetic background of host cells, volume of inoculum, temperature and length of incubation period before nutrient overlay, and rapid freezing and thawing of rickettsial seed. Centrifugation of inoculated cultures at 600 × g resulted in 100% irreversible absorption of rickettsiae to host cells within 5 min, whereas without centrifugation at least 4 hr was required to achieve the same effect. Images PMID:4629250

Wike, David A.; Tallent, George; Peacock, Marius G.; Ormsbee, Richard A.



Spontaneous rupture of the oesophagus  

Microsoft Academic Search

Background: The aim of this study was to evaluate the diagnosis, management and outcome of patients with spontaneous rupture of the oesophagus in a single centre. Methods: Between October 1993 and May 2007, 51 consecutive patients with spontaneous oesophageal rupture were evaluated with contrast radiology and flexible endoscopy. Patients with limited contamination who fulfilled specific criteria were managed by a

S. M. Griffin; P. J. Lamb; J. Shenfine; D. L. Richardson; D. Karat; N. Hayes



Development of gas-phase metallized plaques for electrodes of storage batteries, in particular for nickel oxide electrodes  

NASA Astrophysics Data System (ADS)

Nickel oxide-electrode plaques for alkaline batteries have been developed by carbon vapor deposition plating fiber plaque substrates with nickel from nickelcarbonyo. Carbon felt proved to be a suitable substrate and large (22 x sq 15 sq cm) and thick 3 - 5 mm) plaques could be made from this material. Three metallization devices were constructed, one of which allowed continuous processing with carbonyl gas flowing through the felt; this improved evenness of nickel distribution. The physical properties of the plaques - structure, electric resistance, heat conduction, gas permeation - approximated by simple models and the corresponding calculations were compared with measurements. Nickel oxide electrodes were made from the plaques and were cycled in half-cell arrangements. The project goals concerning nickel sayings, capacity per unit area and current capability were reached.

Linkohr, R.; Schladitz, H.



Quantitative evaluation of carotid arterial plaque surface irregularity  

NASA Astrophysics Data System (ADS)

Recent studies have demonstrated that atherosclerotic plaque surface morphology in the carotid arterial system represents an independent risk factor for embolus formation and subsequent cerebrovascular occlusive events. The primary aim of the current retrospective study is to enhance the clinical utility of this key finding by developing and evaluating objective, quantitative methods for characterizing plaque surface irregularity from Gadolinium-enhanced magnetic resonance angiography (MRA) studies. Nine metrics were analyzed for correlation with percent stenosis in 78 arteries from 43 patients with carotid artery disease. Most of the metrics comprised measurements obtained from a surface model of the stenotic lesion derived from the MRA via the Marching Cubes algorithm with application of the Isosurface Deformable Model. Percent stenosis was determined through real-time volume rendering of 3D MIP MRA studies in Vitrea2. Six of the analyzed metrics revealed significant correlation to percent stenosis (p<0.01). Reproducibility of all metrics was evaluated in a set of 14 randomly selected arteries from 13 patients by way of a single-trial, two-observer analysis. Six of the nine metrics demonstrated significant inter-observer reproducibility by way of single-factor ANOVA analysis (p<0.02). Collectively, the findings reported herein demonstrate an objective and reliable method for quantifying carotid plaque surface irregularity from standard MRA techniques with possible future clinical application in refining risk of ischemic cerebrovascular events and associated need for prophylactic intervention.

Robinson, Joshua; Brevetti, Lucy S.; Yim, Peter J.



Carotid Plaque Assessment using Fast 3D Isotropic-Resolution Black-Blood MRI  

PubMed Central

Black-blood MRI is a promising tool for carotid atherosclerotic plaque burden assessment and compositional analysis. However, current sequences are limited by large slice thickness. Accuracy of measurement can be improved by moving to isotropic imaging but can be challenging for patient compliance due to long scan times. We present a fast isotropic high spatial resolution (0.7×0.7×0.7mm) 3D black-blood sequence (3D-MERGE) covering the entire cervical carotid arteries within 2 minutes thus ensuring patient compliance and diagnostic image quality. The sequence is optimized for vessel wall imaging of the carotid bifurcation based on its signal properties. The optimized sequence is validated on patients with significant carotid plaque. Quantitative plaque morphology measurements and SNR measures show that 3D MERGE provides good blood suppression and comparable plaque burden measurements to existing MRI protocols. 3D-MERGE is a promising new tool for fast and accurate plaque burden assessment in patients with atherosclerotic plaque. PMID:20941742

Balu, Niranjan; Yarnykh, Vasily L.; Chu, Baocheng; Wang, Jinnan; Hatsukami, Thomas; Yuan, Chun



Diffusion en régime permanent d'un champ magnétique glissant dans une plaque ferromagnétique  

NASA Astrophysics Data System (ADS)

We determine the magnetic vector potential for a ferromagnetic plate in the steady state conditions with eddy currents which are induced by sliding field currents. Our plate has non linear magnetic B(H) characteristic. We deduce the cyclic impedance of the field coils and the visualizations of the induction and the permeability of the plate as a function of both the magnitude of field current and the slip frequency. On détermine en régime permanent le potentiel vecteur magnétique dans une plaque ferromagnétique en présence des courants induits par un champ magnétique d'excitation glissant. La plaque a une caractéristique magnétique B(H) non linéaire. On en déduit en fonction de l'intensité du courant d'excitation et de la fréquence de glissement l'impédance cyclique des bobinages d'excitation ainsi que des visualisations de l'induction et de la perméabilité de la plaque.

Guettafi, A.; Quichaud, G.



Coronary plaque imaging with 256-slice multidetector computed tomography: interobserver variability of volumetric lesion parameters with semiautomatic plaque analysis software  

Microsoft Academic Search

The purpose of this study was to evaluate the potential clinical value of coronary plaque imaging with a new generation CT\\u000a scanner and the interobserver variability of coronary plaque assessment with a new semiautomatic plaque analysis application.\\u000a Thirty-five isolated plaques of the left anterior descending coronary artery from 35 patients were evaluated with a new semiautomatic\\u000a plaque analysis application. All

Oliver Klass; Susanne Kleinhans; Matthew J. Walker; Mark Olszewski; Sebastian Feuerlein; Markus Juchems; Martin H. K. Hoffmann



PLAQUE:PLAQUE: What it is and how to get rid of it  

E-print Network

and stick to the teeth. · Some types of plaque cause tooth decay. · Other types of plaque cause gum disease, especially sweets, provide nutrients for the germs that cause tooth decay, as well as those that cause gum--this could harm your gums. Brush Teeth Use any tooth brushing method that is comfortable, but do not scrub

Bandettini, Peter A.


In Vitro Shear Stress Measurements Using Particle Image Velocimetry in a Family of Carotid Artery Models: Effect of Stenosis Severity, Plaque Eccentricity, and Ulceration  

PubMed Central

Atherosclerotic disease, and the subsequent complications of thrombosis and plaque rupture, has been associated with local shear stress. In the diseased carotid artery, local variations in shear stress are induced by various geometrical features of the stenotic plaque. Greater stenosis severity, plaque eccentricity (symmetry) and plaque ulceration have been associated with increased risk of cerebrovascular events based on clinical trial studies. Using particle image velocimetry, the levels and patterns of shear stress (derived from both laminar and turbulent phases) were studied for a family of eight matched-geometry models incorporating independently varied plaque features – i.e. stenosis severity up to 70%, one of two forms of plaque eccentricity, and the presence of plaque ulceration). The level of laminar (ensemble-averaged) shear stress increased with increasing stenosis severity resulting in 2–16 Pa for free shear stress (FSS) and approximately double (4–36 Pa) for wall shear stress (WSS). Independent of stenosis severity, marked differences were found in the distribution and extent of shear stress between the concentric and eccentric plaque formations. The maximum WSS, found at the apex of the stenosis, decayed significantly steeper along the outer wall of an eccentric model compared to the concentric counterpart, with a 70% eccentric stenosis having 249% steeper decay coinciding with the large outer-wall recirculation zone. The presence of ulceration (in a 50% eccentric plaque) resulted in both elevated FSS and WSS levels that were sustained longer (?20 ms) through the systolic phase compared to the non-ulcerated counterpart model, among other notable differences. Reynolds (turbulent) shear stress, elevated around the point of distal jet detachment, became prominent during the systolic deceleration phase and was widely distributed over the large recirculation zone in the eccentric stenoses. PMID:25007248

Kefayati, Sarah; Milner, Jaques S.; Holdsworth, David W.; Poepping, Tamie L.



Functional expression of dental plaque microbiota  

PubMed Central

Dental caries remains a significant public health problem and is considered pandemic worldwide. The prediction of dental caries based on profiling of microbial species involved in disease and equally important, the identification of species conferring dental health has proven more difficult than anticipated due to high interpersonal and geographical variability of dental plaque microbiota. We have used RNA-Seq to perform global gene expression analysis of dental plaque microbiota derived from 19 twin pairs that were either concordant (caries-active or caries-free) or discordant for dental caries. The transcription profiling allowed us to define a functional core microbiota consisting of nearly 60 species. Similarities in gene expression patterns allowed a preliminary assessment of the relative contribution of human genetics, environmental factors and caries phenotype on the microbiota's transcriptome. Correlation analysis of transcription allowed the identification of numerous functional networks, suggesting that inter-personal environmental variables may co-select for groups of genera and species. Analysis of functional role categories allowed the identification of dominant functions expressed by dental plaque biofilm communities, that highlight the biochemical priorities of dental plaque microbes to metabolize diverse sugars and cope with the acid and oxidative stress resulting from sugar fermentation. The wealth of data generated by deep sequencing of expressed transcripts enables a greatly expanded perspective concerning the functional expression of dental plaque microbiota. PMID:25177549

Peterson, Scott N.; Meissner, Tobias; Su, Andrew I.; Snesrud, Erik; Ong, Ana C.; Schork, Nicholas J.; Bretz, Walter A.



Spontaneous rupture of adrenal haemangioma mimicking abdominal aortic aneurysm rupture  

PubMed Central

Serious bleeding from a ruptured adrenal mass limits preoperative diagnostics and can necessitate urgent laparotomy to control blood loss. A 45-year old man underwent an emergency laparotomy due to severe retroperitoneal haemorrhage causing hypovolaemia. Detailed retroperitoneal dissection after splenectomy and clamping of the abdominal aorta revealed bleeding from a ruptured haemangioma of the left adrenal gland. Following a left adrenalectomy, the patient returned to a stable haemodynamic state. Adrenal haemangiomas are rare, but may cause spontaneous life-threatening haemorrhage. PMID:22371732

Ambroziak, Iwona; Holynska-Dabrowska, Katarzyna; Siezieniewska-Skowronska, Zofia; Paluszkiewicz, Andrzej



Partial ACL rupture: an MR diagnosis?  

Microsoft Academic Search

Purpose. We sought to clarify the ability of magnetic resonance imaging (MR) to show partial ante- rior cruciate ligament (ACL) ruptures and to allow dis- tinction of partial from complete ACL ruptures. Materials and methods. Eighty-eight patients were stud- ied by arthroscopy and MR (36 with normal ACLs, 21 with partial ACL ruptures, and 31 with complete ACL ruptures). MR

Lawrence Yao; Amilcare Gentili; Leonard Petrus; Joong K. Lee



Steam generator tube rupture study  

E-print Network

This report describes our investigation of steam generator behavior during a postulated tube rupture accident. Our study was performed using the steam generator, thermal-hydraulic analysis code THERMIT-UTSG. The purpose ...

Free, Scott Thomas



Development of gas phase metallized plaques for electrodes of storage batteries, in particular for nickel oxide electrodes  

NASA Astrophysics Data System (ADS)

Nickel oxide electrode plaques for alkaline batteries were developed by nickel carbonyl vapor deposition plating on large fiber plaque substrates made of carbon. The most promising technique is the one in which carbonyl gas flows continuously through the carbon felt, allowing continuous processing as well as improved uniformity of the nickel distribution. Structural strength, electrical resistance, heat conduction, and gas permeation of the plaques were approximated by simple models which are borne out by experimental comparison it is indicated that electrochemical measurements in half cell arrangements are reached for nickel savings, capacity per unit area, and current capability.

Linkohr, R.; Schladitz, H.



Imaging gate oxide ruptures  

NASA Astrophysics Data System (ADS)

As minimum feature sizes are reduced in MOS silicon devices, dielectric breakdown continues to pose a formidable challenge. A more complete understanding of the failure mechanism which induces oxide rupture has become an absolute necessity in order to meet the advancing yield and reliability requirements of today's complex integrated structures. This paper will present an interesting insight into the nature of dielectric breakdown in MOS transistors produced from a novel cross-sectioning TEM sample preparation method using a focused ion beam tool. By using deductive failure analysis, it was possible to determine the location of the leakage within a 1000 angstroms portion of the transfer gate of a one megabit DRAM. Once localized, a creative combination of conventional glass lapping and focused ion beam techniques were used to produce the thin TEM slice which contained the oxide breakdown. An image of the breakdown was then obtained on a 200 keV TEM. Interestingly, the image revealed that the origin of the breakdown was associated with imperfections in the form of voids in the surface of the silicon substrate. These results proved to be consistent over multiple samples. In this paper a complete description of these images will be presented along with possible theories describing the fundamental origin of these defects.

Mendez, Horacio; Morris, Steve; Tatti, Sudhindra; Dickson, Nicholas; Pyle, Ronald E.



Association between Randall's Plaque and Calcifying Nanoparticles  

NASA Technical Reports Server (NTRS)

Randall's plaques, first described by Alexander Randall in the 1930s, are small subepithelial calcifications in the renal papillae (RP) that also extend deeply into the renal medulla. Despite the strong correlation between the presence of these plaques and the formation of renal stones, the precise origin and pathogenesis of Randall s plaque formation remain elusive. The discovery of calcifying nanoparticles (CNP) and their detection in many calcifying processes of human tissues has raised hypotheses about their possible involvement in renal stone formation. We collected RP and blood samples from 17 human patients who had undergone laparoscopic nephrectomy due to neoplasia. Homogenized RP tissues and serum samples were cultured for CNP. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis were performed on fixed RP samples. Immunohistochemical staining (IHS) was applied on the tissue samples using CNP-specific monoclonal antibody (mAb). Randall s plaques were visible on gross inspection in 11 out of 17 collected samples. Cultures of all serum samples and 13 tissue homogenates had CNP growth within 4 weeks. SEM revealed spherical apatite formations in 14 samples, with calcium and phosphate peaks detected by EDS analysis. IHS was positive in 9 out of 17 samples. A strong link was found between the presence of Randall s plaques and the detection of CNP, also referred to as nanobacteria. These results suggest new insights into the etiology of Randall's plaque formation, and will help us understand the pathogenesis of stone formation. Further studies on this topic may lead us to new approaches on early diagnosis and novel medical therapies of kidney stone formation.

Ciftcioglu, Neva; Vejdani, Kaveh; Lee, Olivia; Mathew, Grace; Aho, Katja M.; Kajander, Olavi; McKay, David S.; Jones, Jeff A.; Hayat, Matthew; Stoller, Marshall L.



Rupture process of the 2013 Okhotsk deep mega earthquake from iterative backprojection and compress sensing methods  

NASA Astrophysics Data System (ADS)

On May 24th 2013 a Mw 8.3 normal faulting earthquake occurred at a depth of approximately 600 km beneath the sea of Okhotsk, Russia. It is a rare mega earthquake that ever occurred at such a great depth. We use the time-domain iterative backprojection (IBP) method [1] and also the frequency-domain compressive sensing (CS) technique[2] to investigate the rupture process and energy radiation of this mega earthquake. We currently use the teleseismic P-wave data from about 350 stations of USArray. IBP is an improved method of the traditional backprojection method, which more accurately locates subevents (energy burst) during earthquake rupture and determines the rupture speeds. The total rupture duration of this earthquake is about 35 s with a nearly N-S rupture direction. We find that the rupture is bilateral in the beginning 15 seconds with slow rupture speeds: about 2.5km/s for the northward rupture and about 2 km/s for the southward rupture. After that, the northward rupture stopped while the rupture towards south continued. The average southward rupture speed between 20-35 s is approximately 5 km/s, lower than the shear wave speed (about 5.5 km/s) at the hypocenter depth. The total rupture length is about 140km, in a nearly N-S direction, with a southward rupture length about 100 km and a northward rupture length about 40 km. We also use the CS method, a sparse source inversion technique, to study the frequency-dependent seismic radiation of this mega earthquake. We observe clear along-strike frequency dependence of the spatial and temporal distribution of seismic radiation and rupture process. The results from both methods are generally similar. In the next step, we'll use data from dense arrays in southwest China and also global stations for further analysis in order to more comprehensively study the rupture process of this deep mega earthquake. Reference [1] Yao H, Shearer P M, Gerstoft P. Subevent location and rupture imaging using iterative backprojection for the 2011 Tohoku Mw 9.0 earthquake. Geophysical Journal International, 2012, 190(2): 1152-1168. [2]Yao H, Gerstoft P, Shearer P M, et al. Compressive sensing of the Tohoku-Oki Mw 9.0 earthquake: Frequency-dependent rupture modes. Geophysical Research Letters, 2011, 38(20).

Qin, W.; Yin, J.; Yao, H.



Alliance ruptures and rupture resolution in cognitive–behavior therapy: A preliminary task analysis  

Microsoft Academic Search

An initial ideal, rational model of alliance rupture and rupture resolution provided by cognitive–behavioral therapy (CBT) experts was assessed and compared with empirical observations of ruptures and their resolution in two cases of successful CBT. The initial rational model emphasized nondefensive acknowledgment and exploration of the rupture. Results indicated differences between what therapists think they should do to resolve ruptures

Helen Aspland; Susan Llewelyn; Gillian E. Hardy; Michael Barkham; William Stiles



Pigmented epidermal plaques in three dogs.  


Papillomavirus was identified in pigmented epidermal plaques (PEP) from three dogs: a miniature schnauzer with hyperadrenocorticism and hypoglobulinemia, an American Staffordshire terrier with hypoglobulinemia, and a Pomeranian with unconfirmed hypothyroidism. Squamous cell carcinoma (SCC) arose within several plaques in the Pomeranian. Clinical improvement coincided in the first two cases with treatment of the concurrent disease and the administration of low-dose oral interferon-alpha. This is the first report of PEP in an American Staffordshire terrier and a Pomeranian. The potential for malignant transformation of PEP to SCC emphasizes the need for recognition and clinical management of PEP. PMID:15347622

Stokking, Laura B; Ehrhart, Eugene J; Lichtensteiger, Carol A; Campbell, Karen L



Exocytosis of polymorphonuclear leukocyte lysosomal contents induced by dental plaque.  

PubMed Central

Rabbit polymorphonuclear leukocytes were incubated with a sonically treated suspension of pooled dental plaque to determine if the plaque would induce release of lysosomal enzymes from the polymorphonuclear leukocytes. Cells incubated with plaque at 37 degrees C released significantly greater amounts of the lysosomal enzymes, beta-glucuronidase and lysozyme, than did cells incubated with plaque at 0 degrees C or without plaque at 37 degrees C. This response was both dose and time dependent. Release of the cytoplasmic enzyme lactate dehydrogenase was minimal, and there were no significant differences in lactate dehydrogenase release between cells at 0 and 37 degrees C, or without plaque. These results indicate that dental plaque can induce the selective release of lysosomal enzymes, which could be involved in the periodontal injury produced by dental plaque. PMID:561032

White, R R; Montgomery, E H



Coronary CT Angiography in the Quantitative Assessment of Coronary Plaques  

PubMed Central

Coronary computed tomography angiography (CCTA) has been recently evaluated for its ability to assess coronary plaque characteristics, including plaque composition. Identification of the relationship between plaque composition by CCTA and patient clinical presentations may provide insight into the pathophysiology of coronary artery plaque, thus assisting identification of vulnerable plaques which are associated with the development of acute coronary syndrome. CCTA-generated 3D visualizations allow evaluation of both coronary lesions and lumen changes, which are considered to enhance the diagnostic performance of CCTA. The purpose of this review is to discuss the recent developments that have occurred in the field of CCTA with regard to its diagnostic accuracy in the quantitative assessment of coronary plaques, with a focus on the characterization of plaque components and identification of vulnerable plaques. PMID:25162010



Association between Randall's Plaque and Calcifying Nanoparticles  

NASA Technical Reports Server (NTRS)

Randall initially described calcified subepithelial papillary plaques, which he hypothesized as nidi for kidney stone formation. The discovery of calcifying nanoparticles (CNP) in many calcifying processes of human tissues has raised another hypothesis about their possible involvement in urinary stone formation. This research is the first attempt to investigate the potential association of these two hypotheses. We collected renal papilla and blood samples from 17 human patients who had undergone laparoscopic nephrectomy due to neoplasia. Immunohistochemical staining (IHS) was applied on the tissue samples using monoclonal antibody 8D10 (mAb) against CNP. Homogenized papillary tissues and serum samples were cultured for CNP. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis were performed on fixed papillary samples. Randall's plaques were visible on gross inspection in 11 out of 17 collected samples. IHS was positive for CNP antigen in 8 of these 11 visually positive samples, but in only 1 of the remaining 6 samples. SEM revealed spherical apatite formations in 14 samples, all of which had calcium and phosphate peaks detected by EDS analysis. From this study, there was some evidence of a link between the presence of Randall's plaques and the detection of CNP, also referred to as nanobacteria. Although causality was not demonstrated, these results suggest that further studies with negative control samples should be made to explore the etiology of Randall's plaque formation, thus leading to a better understanding of the pathogenesis of stone formation.

Citfcioglu, Neva; Vejdani, Kaveh; Lee, Olivia; Mathew, Grace; Aho, Katja M.; Kajander, Olavi; McKay, David S.; Jones, Jeffrey A.; Feiveson, Alan H.; Stoller, Marshall L.



Interstitial granulomatous dermatitis with plaques and arthritis.  


Interstitial granulomatous dermatitis and arthritis (IGDA) is a rare disease entity with female predominance. The case of a 53-year-old woman with erythemas, plaques and nodules associated with polyarthritis is presented. She was treated with cyclosporin A, with improvement of the joint affliction and complete clearance of skin lesions. The differential diagnosis of IGDA is discussed briefly. PMID:14579165

Wollina, U; Schönlebe, J; Unger, L; Weigel, K; Köstler, E; Nüsslein, H



Interstitial granulomatous dermatitis with plaques and arthritis  

Microsoft Academic Search

Interstitial granulomatous dermatitis and arthritis (IGDA) is a rare disease entity with female predominance. The case of a 53-year-old woman with erythemas, plaques and nodules associated with polyarthritis is presented. She was treated with cyclosporin A, with improvement of the joint affliction and complete clearance of skin lesions. The differential diagnosis of IGDA is discussed briefly.

U. Wollina; J. Schönlebe; L. Unger; K. Weigel; E. Köstler; H. Nüsslein



Assessment of plaque composition by intravascular ultrasound and near-infrared spectroscopy: from PROSPECT I to PROSPECT II.  


Atherosclerosis is the main cause of coronary artery disease (CAD), which is today the leading cause of death worldwide and will continue to be the first in the world in 2030. Vulnerable coronary plaques are usually characterized by a high content of necrotic core, a thin inflamed fibrous cap (intense accumulation of macrophages) and scarce presence of smooth muscle cells. None of these characteristics can be estimated by coronary angiography, which on the contrary underestimates the magnitude of atherosclerotic burden, particularly in earlier stage disease when positive vascular remodeling may allow "normal" lumen caliber despite substantial vascular wall plaque. The recognition of the ubiquity of substantial but non-flow limiting lesions that may be at high risk for subsequent plaque rupture has resulted in a paradigm shift in thinking about the pathophysiology of CAD, with the focus no longer solely on the degree of arterial luminal narrowing. This growing need for more information about coronary atherosclerosis in order to identify patients and lesions at risk for complications during PCI and for future adverse cardiac events has been the primary impetus for the development of novel intracoronary imaging methods able to detect plaque composition, in particular presence of a necrotic core/lipid pool, such as intravascular ultrasound virtual histology and near-infrared spectroscopy. These imaging technologies and their clinical and clinical/research applications are discussed in detail. PMID:24931516

Brugaletta, Salvatore; Sabaté, Manel



Requirements for imaging vulnerable plaque in the coronary artery using a coded aperture imaging system  

NASA Astrophysics Data System (ADS)

A coded aperture1 plate was employed on a conventional gamma camera for 3D single photon emission computed tomography (SPECT) imaging on small animal models. The coded aperture design was selected to improve the spatial resolution and decrease the minimum detectable activity (MDA) required to image plaque formation in the APoE (apolipoprotein E) gene deficient mouse model when compared to conventional SPECT techniques. The pattern that was tested was a no-two-holes-touching (NTHT) modified uniformly redundant array (MURA) having 1,920 pinholes. The number of pinholes combined with the thin sintered tungsten plate was designed to increase the efficiency of the imaging modality over conventional gamma camera imaging methods while improving spatial resolution and reducing noise in the image reconstruction. The MDA required to image the vulnerable plaque in a human cardiac-torso mathematical phantom was simulated with a Monte Carlo code and evaluated to determine the optimum plate thickness by a receiver operating characteristic (ROC) yielding the lowest possible MDA and highest area under the curve (AUC). A partial 3D expectation maximization (EM) reconstruction was developed to improve signal-to-noise ratio (SNR), dynamic range, and spatial resolution over the linear correlation method of reconstruction. This improvement was evaluated by imaging a mini hot rod phantom, simulating the dynamic range, and by performing a bone scan of the C-57 control mouse. Results of the experimental and simulated data as well as other plate designs were analyzed for use as a small animal and potentially human cardiac imaging modality for a radiopharmaceutical developed at Bristol-Myers Squibb Medical Imaging Company, North Billerica, MA, for diagnosing vulnerable plaques. If left untreated, these plaques may rupture causing sudden, unexpected coronary occlusion and death. The results of this research indicated that imaging and reconstructing with this new partial 3D algorithm improved the SNR, spatial resolution, dynamic range of 4:1 to 6:1, and decreased the MDA required at the site of a plaque by twofold in comparison with other nuclear medicine imaging methods. Recommendations to increase the field of view (FOV) along with a better imaging geometry would enable placement of larger objects (human heart included) within the fully encoded FOV while improving spatial resolution, magnification factors, and efficiency. Further improvements to the algorithm and imaging system may enable novel vulnerable plaque imaging and early detection of coronary artery disease. 1See definitions beginning on page xvii.

Tozian, Cynthia


In vivo imaging reveals sigmoidal growth kinetic of ?-amyloid plaques  

PubMed Central

A major neuropathological hallmark of Alzheimer’s disease is the deposition of amyloid plaques in the brains of affected individuals. Amyloid plaques mainly consist of fibrillar ?-amyloid, which is a cleavage product of the amyloid precursor protein. The amyloid-cascade-hypothesis postulates A? accumulation as the central event in initiating a toxic cascade leading to Alzheimer’s disease pathology and, ultimately, loss of cognitive function. We studied the kinetics of ?-amyloid deposition in Tg2576 mice, which overexpress human amyloid precursor protein with the Swedish mutation. Utilizing long-term two-photon imaging we were able to observe the entire kinetics of plaque growth in vivo. Essentially, we observed that plaque growth follows a sigmoid-shaped curve comprising a cubic growth phase, followed by saturation. In contrast, plaque density kinetics exhibited an asymptotic progression. Taking into account the fact that a critical concentration of A? is required to seed new plaques, we can propose the following kinetic model of ?-amyloid deposition in vivo. In the early cubic phase, plaque growth is not limited by A? concentration and plaque density increases very fast. During the transition phase, plaque density stabilizes whereas plaque volume increases strongly reflecting a robust growth of the plaques. In the late asymptotic phase, A? peptide production becomes rate-limiting for plaque growth. In conclusion, the present study offers a direct link between in vitro and in vivo studies facilitating the translation of A?-lowering strategies from laboratory models to patients. PMID:24678659



Carotid atherosclerotic plaques: proteomics study after a low-abundance protein enrichment step.  


Atherosclerosis is one of the most important causes of cardiovascular and cerebrovascular events. Although phenotypic differentiation between stable and unstable plaques is currently possible, proteomic analysis of the atherosclerotic plaque could offer a global view of the atherosclerosis pathology. With the objective to highlight the detection of low-abundance proteins, we reduced the dynamic range of proteins by combinatorial peptide ligand library treatment of human carotid artery atherosclerotic plaques. After enrichment step, abundance of major proteins was decreased, revealing different protein profiles as assessed by both SDS-polyacrylamide gel electrophoresis and two-dimensional electrophoresis comparative analyses. Identification of proteins that were contained in a spot allowed finding large differences between noncomplicated and complicated plaques from carotid atherosclerotic lesions. Novel low-abundance proteins were detected correlating very well with biological alterations related to atherosclerosis (heat shock protein 27 (HSP27) isoforms, aldehyde dehydrogenase, moesin, Protein kinase C delta-binding protein, and inter-? trypsin inhibitor family heavy chain-related protein (ITIH4)). At the same time, the differential expression of known proteins of interest such as hemoglobin ?-chain and heat shock protein 27 between noncomplicated and hemorrhagic complicated plaques was maintained after enrichment step. The detection of different isoforms of a low-abundance protein such as heat shock protein 27 species was actually improved after enrichment of tissue protein extracts. All of these findings clearly support further investigations in view to confirm the role of these proteins as possible biomarkers. PMID:22287176

Malaud, Eric; Piquer, Dominique; Merle, Delphine; Molina, Laurence; Guerrier, Luc; Boschetti, Egisto; Saussine, Max; Marty-Ané, Charles; Albat, Bernard; Fareh, Jeannette



Elbow tendinopathy and tendon ruptures: epicondylitis, biceps and triceps ruptures.  


Lateral and medial epicondylitis are common causes of elbow pain in the general population, with the lateral variety being more common than the medial by a ratio reportedly ranging from 4:1 to 7:1. Initially thought to be an inflammatory condition, epicondylitis has ultimately been shown to result from tendinous microtearing followed by an incomplete reparative response. Numerous nonoperative and operative treatment options have been employed in the treatment of epicondylitis, without the emergence of a single, consistent, universally accepted treatment protocol. Tendon ruptures about the elbow are much less frequent, but result in more significant disability and loss of function. Distal biceps tendon ruptures typically occur in middle-aged males as a result of an event that causes a sudden, eccentric contraction of the biceps. Triceps tendon ruptures are exceedingly rare but usually have a similar etiology with a forceful eccentric contraction of the triceps that causes avulsion of the tendon from the olecranon. The diagnosis of these injuries is not always readily made. Complete ruptures of the biceps or triceps tendons have traditionally been treated surgically with good results. With regard to biceps ruptures, there continues to be debate about the best surgical approach, as well as the best method of fixation of tendon to bone. This article is not meant to be an exhaustive review of the broad topics of elbow tendinopathy and tendon ruptures, but rather is a review of recently published information on the topics that will assist the clinician in diagnosis and management of these conditions. PMID:19258160

Rineer, Craig A; Ruch, David S



Increased brain iron coincides with early plaque formation in a mouse model of Alzheimer's disease  

Microsoft Academic Search

Elevated brain iron content, which has been observed in late-stage human Alzheimer's disease, is a potential target for early diagnosis. However, the time course for iron accumulation is currently unclear. Using the PSAPP mouse model of amyloid plaque formation, we conducted a time course study of metal ion content and distribution [iron (Fe), copper (Cu), and zinc (Zn)] in the

A. C. Leskovjan; L. Miller; A. Kretlow; A. Lanzirotti; R. Barrea; S. Vogt



Increased brain iron coincides with early plaque formation in a mouse model of Alzheimer's disease  

Microsoft Academic Search

Elevated brain iron content, which has been observed in late-stage human Alzheimer's disease, is a potential target for early diagnosis. However, the time course for iron accumulation is currently unclear. Using the PSAPP mouse model of amyloid plaque formation, we conducted a time course study of metal ion content and distribution [iron (Fe), copper (Cu), and zinc (Zn)] in the

Andreana C. Leskovjan; Ariane Kretlow; Antonio Lanzirotti; Raul Barrea; Stefan Vogt; Lisa M. Miller



ADAM-10 could mediate cleavage of N-cadherin promoting apoptosis in human atherosclerotic lesions leading to vulnerable plaque: a morphological and immunohistochemical study.  


Atherosclerosis remains a major cause of mortality. Whereas the histopathological progression of atherosclerotic lesions is well documented, much less is known about the development of unstable or vulnerable plaque, which can rupture leading to thrombus, luminal occlusion and infarct. Apoptosis in the fibrous cap, which is rich in vascular smooth muscle cells (VSMCs) and macrophages, and its subsequent weakening or erosion seems to be an important regulator of plaque stability. The aim of our study was to improve our knowledge on the biological mechanisms that cause plaque instability in order to develop new therapies to maintain atherosclerotic plaque stability and avoid its rupture. In our study, we collected surgical specimens from atherosclerotic plaques in the right or left internal carotid artery of 62 patients with evident clinical symptoms. Histopathology and histochemistry were performed on wax-embedded sections. Immunohistochemical localization of caspase-3, N-cadherin and ADAM-10 was undertaken in order to highlight links between apoptosis, as expressed by caspase-3 immunostaining, and possible roles of N-cadherin, a cell-cell junction protein in VSMCs and macrophages that provides a pro-survival signal reducing apoptosis, and ADAM-10, a "disintegrin and metalloproteases" that is able to cleave N-cadherin in glioblastomas. Our results showed that when apoptosis, expressed by caspase-3 immunostaining, increased in the fibrous cap, rich in VSMCs and macrophages, the expression of N-cadherin decreased. The decreased N-cadherin expression, in turn, was linked to increased ADAM-10 expression. This study shows that apoptotic events are probably involved in the vulnerability of atherosclerotic plaque. PMID:24985126

Musumeci, Giuseppe; Coleman, Raymond; Imbesi, Rosa; Magro, Gaetano; Parenti, Rosalba; Szychlinska, Marta Anna; Scuderi, Rosario; Cinà, Claudio Salvatore; Castorina, Sergio; Castrogiovanni, Paola



Cervical ruptures in midtrimester abortions.  


2 groups of patients are at risk of traumatic complication after midtrimester abortion: older multiparous women (uterine ruptures) and young primigravid women (cervical ruptures). While the occurrence of uterine ruptures in the former class can be reduced by selective use of abortifacient agents, and avoidance of amnioinfusions and intravenous oxytocin, the occurrence of cervical ruptures continues to be high. From May 1974 through May 1978, 780 women underwent midtrimester abortion by various techniques. 12 patients (1.5%) sustained cervical injuries, 11 of whom were nulliparous aged 16 to 25 years. Intra-amniotic and extra-ovular methods alike produced cervical injuries. The combined method of induction increases the likelihood of damaging the cervix. Oxytocic augmentation, however, does not appear to increase its incidence. Nor does a shorter induction-abortion interval, according to the evidence. Since laminaria tents did not prevent cervical injuries, none of the presently available methods offers any protection. Nevertheless, it may be that cervical injuries can be prevented if midtrimester abortions are undertaken between 13 and 15 weeks of pregnancy. Cervical ruptures can also go unnoticed and cause future obstetric problems; the authors therefore emphasize the importance of routine cervical inspection in all patients. PMID:12335921

Rajan, R; Usha, K R



Dual-mode ultrasound arrays for image-guided targeting of atheromatous plaques  

NASA Astrophysics Data System (ADS)

A feasibility study was undertaken in order to investigate alternative noninvasive treatment options for atherosclerosis. In particular, the aim of this study was to investigate the potential use of Dual-Mode Ultrasound Arrays (DMUAs) for image guided treatment of atheromatous plaques. DMUAs offer a unique treatment paradigm for image-guided surgery allowing for robust image-based identification of tissue targets for localized application of HIFU. In this study we present imaging and therapeutic results form a 3.5 MHz, 64-element fenestrated prototype DMUA for targeting lesions in the femoral artery of familial hypercholesterolemic (FH) swine. Before treatment, diagnostic ultrasound was used to verify the presence of plaque in the femoral artery of the swine. Images obtained with the DMUA and a diagnostic (HST 15-8) transducer housed in the fenestration were analyzed and used for guidance in targeting of the plaque. Discrete therapeutic shots with an estimated focal intensity of 4000-5600 W/cm2 and 500-2000 msec duration were performed at several planes in the plaque. During therapy, pulsed HIFU was interleaved with single transmit focus imaging from the DMUA and M2D imaging from the diagnostic transducer for further analysis of lesion formation. After therapy, the swine's were recovered and later sacrificed after 4 and 7 days for histological analysis of lesion formation. At sacrifice, the lower half of the swine was perfused and the femoral artery with adjoining muscle was fixed and stained with H&E to characterize HIFU-induced lesions. Histology has confirmed that localized thermal lesion formation within the plaque was achieved according to the planned lesion maps. Furthermore, the damage was confined to the plaque tissue without damage to the intima. These results offer the promise of a new treatment potentially suited for vulnerable plaques. The results also provide the first real-time demonstration of DMUA technology in targeting fine tissue structures for precise lesion formation in the presence or arterial pulsation and tissue motion. In this paper, we show results from targeting both proximal and distal sides of the vessel wall with a series of 5 - 7 discrete shots in each plane (typically three planes per plaque). Experiments to demonstrate a full treatment forming contiguous lesion within the target plaque are currently underway.

Ballard, John R.; Casper, Andrew J.; Liu, Dalong; Haritonova, Alyona; Shehata, Islam A.; Troutman, Mitchell; Ebbini, Emad S.



Atherosclerotic plaque characterization by spatial and temporal speckle pattern analysis  

NASA Astrophysics Data System (ADS)

Improved methods are needed to identify the vulnerable coronary plaques responsible for acute myocardial infraction or sudden cardiac death. We describe a method for characterizing the structure and biomechanical properties of atherosclerotic plaques based on speckle pattern fluctuations. Near-field speckle images were acquired from five human aortic specimens ex vivo. The speckle decorrelation time constant varied significantly for vulnerable aortic plaques (? = 40 ms) versus stable plaques (? = 400 ms) and normal aorta (? = 500 ms). These initial results indicate that different atherosclerotic plaque types may be distinguished by analysis of temporal and spatial speckle pattern fluctuations.

Tearney, Guillermo J.; Bouma, Brett E.



Ruptures of the rotator cuff.  

PubMed Central

Through the use of improved diagnostic techniques, including arthrography and arthroscopy, ruptures of the rotator cuff that previously might not have been recognized are now being identified more frequently. In most cases the symptoms are relatively mild and respond satisfactorily to rest and therapy. Occasionally, however, there is severe, persistent disability despite treatment. These ruptures require surgical repair. In such cases the data obtained from special investigations help the surgeon select the appropriate surgical approach and repair technique. An imaginative program of physiotherapy before and after the operation contributes greatly to a satisfactory result. Images FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 7 PMID:7437980

Ha'eri, G B



Analyzing Single-Event Gate Ruptures In Power MOSFET's  

NASA Technical Reports Server (NTRS)

Susceptibilities of power metal-oxide/semiconductor field-effect transistors (MOSFET's) to single-event gate ruptures analyzed by exposing devices to beams of energetic bromine ions while applying appropriate bias voltages to source, gate, and drain terminals and measuring current flowing into or out of each terminal.

Zoutendyk, John A.



Magnitude scaling of the near fault rupture directivity pulse  

Microsoft Academic Search

Current ground motion models all assume monotonically increasing spectral amplitude at all periods with increasing magnitude. However, near fault recordings from recent earthquakes confirm that the near fault fault-normal forward rupture directivity velocity pulse is a narrow band pulse whose period increases with magnitude. This magnitude dependence of the period of the near fault pulse is expected from theory, because

Paul G. Somerville



Predominant cultivable flora isolated from human root surface caries plaque.  

PubMed Central

Plaque samples were obtained from tooth surfaces exhibiting typical lesions of root surface caries and were immediately cultured by a continuous anaerobic procedure. The bacterial composition of root caries flora was determined on individual samples. Representative isolates from each specimen were characterized by morphological and physiological criteria. In addition, fluorescent antibody reagents were used to confirm the identification of Streptococcus mutans and Actinomyces viscosus. The plaque samples could be divided into two groups on the basis of the presence or absence of S. mutans in the plaque. In group I plaques, S. mutans comprised 30 percent of the total cultivable flora. S. sanguis was either not found or was present in very low number. In group II plaques, S. mutans was not detected, and S. sanguis formed 48 percent of the total plaque flora. A. viscosus was the dominant organism in all plaque samples, accounting for 47 percent of the group I isolates and 41 percent of the group II isolates. PMID:1091550

Syed, S A; Loesche, W J; Pape, H L; grenier, E



Simple method for plating Escherichia coli bacteriophages forming very small plaques or no plaques under standard conditions.  


The use of low concentrations (optimally 2.5 to 3.5 microg/ml, depending on top agar thickness) of ampicillin in the bottom agar of the plate allows for formation of highly visible plaques of bacteriophages which otherwise form extremely small plaques or no plaques on Escherichia coli lawns. Using this method, we were able to obtain plaques of newly isolated bacteriophages, propagated after induction of prophages present in six E. coli O157:H(-) strains which did not form plaques when standard plating procedures were employed. PMID:18586961

Lo?, Joanna M; Golec, Piotr; Wegrzyn, Grzegorz; Wegrzyn, Alicja; Lo?, Marcin



Interstitial granulomatous dermatitis with plaques and arthritis.  


Interstitial granulomatous dermatitis (IGD) is a histopathological disorder characterised by an infiltration of the reticular dermis with a predominance of interstitial and palisadic histiocytes with a few areas of degenerating collagen bundles associated with a variable number of polynuclear neutrophils and eosinophils. There are several clinical conditions with a pattern of IGD. The linear form associated with arthritis was the first variety described. There is also a second form, which presents with plaques. This variety may be associated with arthritis, use of certain drugs or the presence of different systemic disorders. We report a case of IGD with plaques and arthritis. We discuss the differential clinical and histological diagnosis with other inflammatory skin lesions, which may be associated with joint disorders and collagen degeneration. We believe that it should be considered in patients presenting with arthritis and skin lesions. PMID:12804998

Bañuls, José; Betlloch, Isabel; Botella, Rafael; Jiménez, Maria José; Blanes, Mar; Pascual, José Carlos; Belinchón, Isabel; Silvestre, Juan Francisco



Enucleation versus plaque irradiation for choroidal melanoma.  


The Collaborative Ocular Melanoma Study (COMS) is an international, multicenter-controlled study. The organization includes an Executive Committee, Steering Committee, 6 Central Units, 32 Clinical Centers, and a Data and Safety Monitoring Committee. Scientifically, the COMS consists of (1) a randomized trial of patients with medium choroidal melanoma treated with enucleation versus iodine-125 plaque irradiation, (2) a randomized trial of patients with large choroidal melanoma treated with enucleation versus preenucleation external beam irradiation and enucleation, and (3) a prospective observational study of patients with small choroidal melanoma to determine whether a randomized trial of treatment is appropriate. In design and conduct of the COMS, special consideration is given to biostatistics and sample size considerations, iodine-125 plaque irradiation of choroidal melanoma, and coordinated ocular melanoma research. Recruitment is in progress. However, the pool of eligible patients is limited and the COMS needs the continued support and cooperation of ophthalmologists throughout the United States and Canada. PMID:3174030

Straatsma, B R; Fine, S L; Earle, J D; Hawkins, B S; Diener-West, M; McLaughlin, J A



Earliest Known Roman London Plaque Discovered  

NSDL National Science Digital Library

Earlier today, archaeologists working on a massive dig on the southern banks of the River Thames uncovered the oldest known plaque inscribed with the city's Roman name, Londinium. While the exact date of the plaque is unknown, it is believed to date from between 50 and 150 AD, and would most likely have been placed on some type of building or in a shrine. Equally important, the plaque offers some initial concrete evidence that there was an emerging merchant class in London during this period. The actual location of the plaque's discovery is near the junction of what were three key roads in Roman Britain, and the finding represents only a small portion of what may be unearthed in this 40-week archaeology project.The first link is to a recent news story about the recent find in London. The second site leads to the Council for British Archaeology, which features numerous links to ongoing research projects within Britain and frequent updates about new findings from the field. The third site offers some perspective on the historical notion of Roman Britain, and particularly how scholars understand that epoch. The fourth site is a link to the complete work "Roman Roads in Britain," a historical study that seeks to describe and delineate the exact location of these very important Roman pathways. Information about the Museum of London, which is working jointly on this project, is provided by the fifth link. The last link, Britannia, is a nice omnibus listing of sites dealing with various aspects of Roman Britain history and archaeology, provided by the Dalton School in New York.

Grinnell, Max



A Retrospective Analysis of Ruptured Breast Implants  

PubMed Central

Background Rupture is an important complication of breast implants. Before cohesive gel silicone implants, rupture rates of both saline and silicone breast implants were over 10%. Through an analysis of ruptured implants, we can determine the various factors related to ruptured implants. Methods We performed a retrospective review of 72 implants that were removed for implant rupture between 2005 and 2014 at a single institution. The following data were collected: type of implants (saline or silicone), duration of implantation, type of implant shell, degree of capsular contracture, associated symptoms, cause of rupture, diagnostic tools, and management. Results Forty-five Saline implants and 27 silicone implants were used. Rupture was diagnosed at a mean of 5.6 and 12 years after insertion of saline and silicone implants, respectively. There was no association between shell type and risk of rupture. Spontaneous was the most common reason for the rupture. Rupture management was implant change (39 case), microfat graft (2 case), removal only (14 case), and follow-up loss (17 case). Conclusions Saline implants have a shorter average duration of rupture, but diagnosis is easier and safer, leading to fewer complications. Previous-generation silicone implants required frequent follow-up observation, and it is recommended that they be changed to a cohesive gel implant before hidden rupture occurs.

Baek, Woo Yeol; Lew, Dae Hyun



Traumatic pericardial rupture with skeletonized phrenic nerve  

Microsoft Academic Search

BACKGROUND: Traumatic pericardial rupture is a rare presentation. Pericardial rupture itself is asymptomatic unless complicated by either hemorrhage or herniation of the heart through the defect. Following diagnosis surgical repair of the pericardium is indicated because cardiac herniation may result in vascular collapse and sudden death. OBJECTIVES: Here we present a case of traumatic, non-herniated pericardial rupture with complete skeletonization

Zain Khalpey; Taufiek K Rajab; Jan D Schmitto; Philipp C Camp



Conversion of plaque-area measurements to plaque index scores. An assessment of variation and discriminatory power.  


Plaque areas recorded graphically or photographically provide a permanent record of plaque accumulations on teeth at a moment in time. As such, these records could be re-evaluated and converted into other index scores. The purpose of this study was to determine the reproducibility of scoring a plaque index from previously recorded plaque areas and to compare such scores with the original scores of the same index. A randomised blind, crossover study comparing 5 treatments for plaque inhibition scored by plaque area and index was chosen. 2 examiners, the original scorer PRH and another, NC, 2x scored the plaque area tooth charts according to the criteria of the plaque index system used in the original study. Standard deviations of the differences showed intra-examiner repeatability to be high particularly for the original examiner. Inter-examiner reproducibility for the original index scores was considered good but less than for intra-examiner repeatability. Correlation coefficients were complimentary to the differences analysis, being very high within examiners and less high for between examiners and original and rescored index. Separation between distributions of plaque area measurements for consecutive values of the index were particular good for scores 2 versus 3 and 3 versus 4 and less good for 1 versus 2 and 4 versus 5. Reanalysis of the study for treatment differences using rescored data revealed a similar level of significance as using the original data. Rescored index had similar discriminatory power for the study as plaque area and original plaque index when both were derived from the same buccal tooth surfaces. However, discriminatory power was less by comparison with original plaque index derived from the buccal surfaces of all teeth. It is concluded that plaque area provides a permanent record of plaque distribution which can be converted into index data at a later date. Such data collection could make possible comparisons between studies using different indices. PMID:10412846

Renton-Harper, P; Claydon, N; Warren, P; Newcombe, R G; Addy, M



Atherosclerotic Aortic Arch Plaques in Acute Ischemic Stroke  

PubMed Central

Background: Atherosclerotic aortic arch plaques (AAP) have been linked to an increased risk of thrombo-embolic events as a cause of acute ischemic stroke of undetermined etiology. Objectives: To find out the presence of atherosclerotic plaques in aortic arch and their potential role as a source of embolism in cerebral infarction of undetermined etiology. Methods: We performed trans-esophageal echocardiography (TEE) and multislice computerized tomography (MSCT) of the aortic arch on 30 patients with acute ischemic stroke of undetermined cause from a total series of 150 non-selected patients with acute ischemic stroke studied prospectively by clinical evaluation, laboratory investigations, cranial computed tomography, color coded duplex ultrasonography of the carotid arteries and transcranial Doppler (TCD). Results: Using trans-esophageal echocardiography eight patients (29.6%) had atherosclerotic aortic arch plaques, while using multislice computerized tomography atherosclerotic aortic arch plaques were revealed in twelve patients (40%). Atherosclerotic aortic arch plaques were significantly related to older age, male gender, hypertension, ischemic heart disease and low-grade atherosclerotic carotid lesions. Multislice computerized tomography of the aortic arch was more sensitive than trans-esophageal echocardiography in detecting the site, size and characters of atherosclerotic aortic arch plaques. Conclusion: Atherosclerotic aortic arch plaques are a frequent finding in patients with acute ischemic stroke of undetermined cause supporting the hypothesis that aortic plaques have embolic potential. In addition, multislice computerized tomography is more sensitive than trans-esophageal echocardiography in detecting atherosclerotic aortic arch plaques and better characterization of these plaques especially relevant one. PMID:22518260

Deif, Randa; El-Sayed, Mohamed; allah, Foad Abd; Baligh, Essam; El-Fayomy, Nervana M.; EzzAt, Loai; Gamal, Heba



Review of diagnostic plaque reduction neutralization tests for flavivirus infection.  


Flavivirus infections (including Japanese encephalitis, West Nile encephalitis and dengue fever/severe dengue) present a worldwide public health problem. Recent climate change may affect the geographical distribution of the arthropod vectors for these viruses and so the risk of flavivirus epidemics may increase. Many methods have been developed for the serological diagnosis of flavivirus infections, such as haemagglutination inhibition assay, enzyme-linked immunosorbent assay, and immunofluorescence in staining. However, the specificity of these assays varies. The plaque reduction neutralizing test (PRNT) using live viruses is currently the 'gold standard' for the differential serodiagnosis of flaviviruses. The specificity of results obtained with PRNT is better than that for other protocols and many laboratories apply the PRNT protocol to the differential serodiagnosis of flaviviruses. Here, recent refinements to the PRNT protocols with genetically modified recombinant viruses or reporter-harbouring virus-like particles are reviewed. Further, the problems associated with the differential serodiagnosis of flaviviruses using PRNT are discussed. PMID:23036176

Maeda, Akihiko; Maeda, Junko



Assessment of coronary arterial plaque by optical coherence tomography.  


The purpose of this study was to analyze the ability of optical coherence tomography (OCT) to identify coronary arterial plaque diagnosed by histologic examination. We examined 166 sections from 108 coronary arterial segments of 40 consecutive human cadavers (24 men and 16 women; mean age 74 +/- 7 years). The plaque type was classified as fibrous (n = 43), fibrocalcific (n = 82), or lipid-rich (n = 41). The accuracy of OCT and intravascular ultrasound (IVUS) in characterizing the plaque type was studied, with the histologic consensus diagnosis serving as the gold standard. OCT, as well as IVUS, had high sensitivity and specificity for characterizing the different types of atherosclerotic plaque. OCT had a higher sensitivity for characterizing lipid-rich plaques than IVUS (85% vs 59%, p = 0.03). In conclusion, the high resolution of OCT permitted evaluation of lipid-rich plaques more accurately than IVUS. PMID:16616021

Kume, Teruyoshi; Akasaka, Takashi; Kawamoto, Takahiro; Watanabe, Nozomi; Toyota, Eiji; Neishi, Yoji; Sukmawan, Renan; Sadahira, Yoshito; Yoshida, Kiyoshi



Intraprocedural plaque protrusion resulting in cerebral embolism during carotid angioplasty with stenting.  


An 82-year-old man with an asymptomatic left high-grade carotid stenosis was treated with carotid artery stenting (CAS) under distal protection. The procedure consisted with predilation with a 5 x 40 mm percutaneous transluminal angioplasty (PTA) balloon, deployment of a 10 x 20 mm self-expandable stent, post-dilation with a 7 x 20 mm PTA balloon, and aspiration of debris with 60 ml of blood. The cervical carotid angiogram immediately after deflation of the distal blocking balloon demonstrated a small in-stent filling defect of the contrast medium that protruded from the anterior wall of the carotid artery. The following cranial carotid angiogram showed abrupt occlusion of the left middle cerebral artery (MCA). Because the in-stent lesion had vanished in the repeat study after recognition of this embolic event, it was suggested that an embolus had been liberated from the in-stent lesion, reaching the left MCA and obliterating it. In this case, the embolus was speculated to originate in the ruptured plaque, which protruded into the stent through the cells of the device and became liberated into the bloodstream. Attention should be paid so as not to overlook any plaque protrusion, which may be seen subsequently as a cerebral embolism on the angiogram obtained immediately after CAS. PMID:18661218

Aikawa, Hiroshi; Kodama, Tomonobu; Nii, Kouhei; Tsutsumi, Masanori; Onizuka, Masanari; Iko, Minoru; Matsubara, Shuko; Etou, Housei; Sakamoto, Kimiya; Kazekawa, Kiyoshi



Numerical simulations of large earthquakes: Dynamic rupture propagation on heterogeneous faults  

USGS Publications Warehouse

Our current conceptions of earthquake rupture dynamics, especially for large earthquakes, require knowledge of the geometry of the faults involved in the rupture, the material properties of the rocks surrounding the faults, the initial state of stress on the faults, and a constitutive formulation that determines when the faults can slip. In numerical simulations each of these factors appears to play a significant role in rupture propagation, at the kilometer length scale. Observational evidence of the earth indicates that at least the first three of the elements, geometry, material, and stress, can vary over many scale dimensions. Future research on earthquake rupture dynamics needs to consider at which length scales these features are significant in affecting rupture propagation. ?? Birkha??user Verlag, Basel, 2004.

Harris, R.A.



Dosimetric Benefit of a New Ophthalmic Radiation Plaque  

SciTech Connect

Purpose: To determine whether the computed dosimetry of a new ophthalmic plaque, EP917, when compared with the standard Collaborative Ocular Melanoma Study (COMS) plaques, could reduce radiation exposure to vision critical structures of the eye. Methods and Materials: One hundred consecutive patients with uveal melanoma treated with COMS radiation plaques between 2007 and 2010 were included in this study. These treatment plans were generated with the use of Bebig Plaque Simulator treatment-planning software, both for COMS plaques and for EP917 plaques using I-125. Dose distributions were calculated for a prescription of 85 Gy to the tumor apex. Doses to the optic disc, opposite retina, lens, and macula were obtained, and differences between the 2 groups were analyzed by standard parametric methods. Results: When compared with the COMS plaques, the EP917 plaques used fewer radiation seeds by an average difference of 1.94 (P<.001; 95% confidence interval [CI], -2.8 to -1.06) and required less total strength of radiation sources by an average of 17.74 U (air kerma units) (P<.001; 95% CI, -20.16 to -15.32). The total radiation doses delivered to the optic disc, opposite retina, and macula were significantly less by 4.57 Gy, 0.50 Gy, and 11.18 Gy, respectively, with the EP917 plaques vs the COMS plaques. Conclusion: EP917 plaques deliver less overall radiation exposure to critical vision structures than COMS treatment plaques while still delivering the same total therapeutic dose to the tumor.

Marwaha, Gaurav, E-mail: [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States) [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States); Cleveland Clinic Foundation, Cleveland, Ohio (United States); Wilkinson, Allan [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States) [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States); Cleveland Clinic Foundation, Cleveland, Ohio (United States); Bena, James [Department of Quantitative Health Sciences, Cleveland Clinic Foundation, Cleveland, Ohio (United States) [Department of Quantitative Health Sciences, Cleveland Clinic Foundation, Cleveland, Ohio (United States); Cleveland Clinic Foundation, Cleveland, Ohio (United States); Macklis, Roger [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States) [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States); Cleveland Clinic Foundation, Cleveland, Ohio (United States); Singh, Arun D. [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States) [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio (United States); Department of Ophthalmic Oncology, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio (United States); Cleveland Clinic Foundation, Cleveland, Ohio (United States)



Dietary trans fatty acids and composition of human atheromatous plaques.  


Dietary fatty acids are incorporated into atheromatous plaques mainly in the form of cholesterol esters. Physicochemical properties of the plaque (e. g. mechanical strength) depend on its fatty acid composition. Trans isomers of unsaturated fatty acids (TFA) are known to reduce the availability of fatty acid precursors for the synthesis of anticoagulant PG(1) and PG(3) prostaglandins. The present study was undertaken to determine the content of trans isomers in atheromatous plaques and to search for correlations between trans isomers in the plaque and adipose tissue. Atheromatous plaques were obtained from 31 patients who underwent surgery due to atherosclerotic stenosis of the abdominal aorta, iliac or femoral arteries. Fatty acids were extracted and separated as methyl esters using gas chromatography (GC) with an internal standard. Correlations were searched for with statistical methods, taking the level of significance as p < 0.05. We found spatial and positional isomers of sixteen- and eighteen-carbon fatty acids in plaques and adipose tissue, with elaidic acid (C18:1 trans-9) being the most abundant. Every plaque and adipose tissue sample contained linolelaidic acid (C18:2 trans-9 trans-12) which is derived exclusively from linoleic acid, as well as conjugated dienes of linoleic acid (CLA) produced during oxidative processes. The presence of trans isomers of fatty acids in the atheromatous plaque seems to be of relevance to plaque formation. Of much concern is the detection of elaidic and linolelaidic acids which adversely affect the physiologically important metabolism of eicosanoids. The TFA pool in adipose tissue has little effect on the amount of these acids in the atheromatous plaque. Apparently, the presence of TFA in atheromatous plaques is the result of processes taking place during plaque formation and maturation. PMID:15309454

Stachowska, Ewa; Do?egowska, Barbara; Chlubek, Dariusz; Weso?owska, Teresa; Ciechanowski, Kazimierz; Gutowski, Piotr; Szumi?owicz, Halina; Turowski, Rados?aw



Traumatically ruptured globes in children.  


This retrospective study was designed to document the etiology of traumatically ruptured globes in children and to determine the prognostic value of several clinical parameters with respect to visual outcome. Forty-six children 16 years of age and under seen in the emergency room over a 2-year period were found to have full thickness penetration of the globe. Fifty-nine percent of injuries occurred during recreational activities, and 59% occurred outside of the home. Boys outnumbered girls by a 6:1 ratio. For children, initial visual acuity proved to be less valuable as a prognostic indicator with regard to final vision than has been reported in adults. Smaller corneal wounds offered better visual outcomes. Four eyes were enucleated. Ten ruptures (22%) were related to activity involving guns. Four of six BB gun injuries were the result of a ricocheted BB. Visual outcomes in gun-related injuries were particularly poor. PMID:7837018

Rudd, J C; Jaeger, E A; Freitag, S K; Jeffers, J B



Achilles tendon rupture in badminton.  

PubMed Central

The typical badminton player with an Achilles tendon rupture is 36 years old and, despite limbering up, is injured at the rear line in a sudden forward movement. He resumes work within three months and has a slight lack of dorsiflexion in the ankle as the main complication. Most patients resume badminton within one year, but some finish their sports career, mainly due to fear of a new injury. The investigation discusses predisposing factors and prophylactic measures. PMID:2605439

Kaalund, S; Lass, P; Høgsaa, B; Nøhr, M




Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF PLAQUE DESCRIBING LION SCULPTURES BY ROLAND HINTON PERRY, NORTHWEST ABUTMENT - Connecticut Avenue Bridge, Spans Rock Creek & Potomac Parkway at Connecticut Avenue, Washington, District of Columbia, DC


59. SAC Plaque, front lawn, building 500, looking east ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

59. SAC Plaque, front lawn, building 500, looking east - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE


Impact de plaques composites : caractérisation et modèles  

NASA Astrophysics Data System (ADS)

We are concerned with the behavior of thin stratified carbon- or glass- epoxy composite plates. The present work is presented as a part of a more wide study carried out which purpose is the numerical simulation of damage evolution within such plates when subjected to a localized transverse low-velocity impact. To establish a correlation between the measured internal damage and the corresponding absorbed energy, from works presented in the literature, is the aim of this one. We first focuse our attention on the typical loading conditions of a direct transverse low-velocity impact. Indeed, we point out the respective role of the impactor/plate contact, indentation and flexion process of the plate on the localization, initiation and propagation of intralaminar cracking and interlaminar delamination. A phenomenological model of interactive evolution of these damages which takes into account the loading and energy absorption process is then proposed, and we identify the interaction between the experimental parameters and the up mentioned damages. We further expose a discussion about some contact law models, and our approach of the loading/structure interaction simulation in terms of the damage phenomenology model presented. Nous nous intéressons au comportement de plaques minces composites stratifiées à fibres longues et à base de carbone/époxyde ou verre/époxyde. Le travail présenté s'insère dans une étude globale visant la simulation numérique de l'évolution de l'endommagement interne des plaques. Le but de cet article est essentiellement de dégager une relation entre l'état d'endommagement mesuré dans la plaque et l'énergie d'impact absorbée correspondante, à partir des travaux exposés dans la littérature. Pour cela, nous présentons notre analyse des conditions de chargement typiques de la sollicitation d'impact transverse direct: nous différencions les, chargements de poinçonnement et de flexion de la plaque sur la localisation, l'initiation et la propagation de la fissuration intralaminaire et du délaminage interlaminaire. Sur la base de cette analyse, nous proposons un modèle phénoménologique d'évolution interactive des dommages tenant compte des modes de chargement et des énergies dissipées, et une identification de l'interaction paramètres expérimentaux/dommages. Nous exposons ensuite notre analyse de modèles de lois de contact par rapport au modèle phénoménologique présenté.

Espinosa, Ch.; Collombet, F.



Endoluminal stent reconstruction of low-grade, symptomatic carotid plaques: a treatment alternative--report of two cases  

PubMed Central

Introduction Medical treatment of low-grade (<50% luminal narrowing) symptomatic carotid stenosis has been the treatment of choice because trial data showed no evident benefit to carotid endarterectomy for these patients. Such patients may have recurrent neurological symptoms despite adequate medical therapy owing to recurrent plaque rupture. In such cases, carotid stenting may represent an option for treatment but has not been tested in trials because of previous failure of carotid endarterectomy to demonstrate any benefit for patients with low-grade carotid stenosis. The cases presented here illustrate the perioperative safety and potential benefit of carotid stenting for such patients with persistent neurological symptoms despite adequate medical therapy. Case material Two patients with low-grade stenosis and recurrent transient ischemic attack or stroke despite antiplatelet therapy were treated with carotid stenting. Both patients were treated after recent ipsilateral neurological events in the absence of an evident cardioembolic source. Carotid plaque ulceration thought to be related to the ischemic events was present in both cases. No perioperative complications were noted. On followup, the patients showed resolution of symptoms and had no new neurological events. Conclusion Carotid stenting of low-grade but symptomatic carotid plaque refractory to medical management represents a surgical option for treatment. Further studies may be warranted to evaluate stenting as a suitable treatment option. PMID:24920988

Shallwani, Hussain; Dumont, Travis M.; Wach, Michael M.; Levy, Elad I.; Siddiqui, Adnan H.



Mechanical stress analysis of a rigid inclusion in distensible material: a model of atherosclerotic calcification and plaque vulnerability.  


The role of atherosclerotic calcification in plaque rupture remains controversial. In previous analyses using finite element model analysis, circumferential stress was reduced by the inclusion of a calcium deposit in a representative human anatomical configuration. However, a recent report, also using finite element analysis, suggests that microscopic calcium deposits increase plaque stress. We used mathematical models to predict the effects of rigid and liquid inclusions (modeling a calcium deposit and a lipid necrotic core, respectively) in a distensible material (artery wall) on mechanical failure under uniaxial and biaxial loading in a range of configurations. Without inclusions, stress levels were low and uniform. In the analytical model, peak stresses were elevated at the edges of a rigid inclusion. In the finite element model, peak stresses were elevated at the edges of both inclusions, with minimal sensitivity to the wall distensibility and the size and shape of the inclusion. Presence of both a rigid and a soft inclusion enlarged the region of increased wall stress compared with either alone. In some configurations, the rigid inclusion reduced peak stress at the edge of the soft inclusion but simultaneously increased peak stress at the edge of the rigid inclusion and increased the size of the region affected. These findings suggest that the presence of a calcium deposit creates local increases in failure stress, and, depending on relative position to any neighboring lipid pools, it may increase peak stress and the plaque area at risk of mechanical failure. PMID:19542489

Hoshino, Tetsuya; Chow, Lori A; Hsu, Jeffrey J; Perlowski, Alice A; Abedin, Moeen; Tobis, Jonathan; Tintut, Yin; Mal, Ajit K; Klug, William S; Demer, Linda L



Mechanical stress analysis of a rigid inclusion in distensible material: a model of atherosclerotic calcification and plaque vulnerability  

PubMed Central

The role of atherosclerotic calcification in plaque rupture remains controversial. In previous analyses using finite element model analysis, circumferential stress was reduced by the inclusion of a calcium deposit in a representative human anatomical configuration. However, a recent report, also using finite element analysis, suggests that microscopic calcium deposits increase plaque stress. We used mathematical models to predict the effects of rigid and liquid inclusions (modeling a calcium deposit and a lipid necrotic core, respectively) in a distensible material (artery wall) on mechanical failure under uniaxial and biaxial loading in a range of configurations. Without inclusions, stress levels were low and uniform. In the analytical model, peak stresses were elevated at the edges of a rigid inclusion. In the finite element model, peak stresses were elevated at the edges of both inclusions, with minimal sensitivity to the wall distensibility and the size and shape of the inclusion. Presence of both a rigid and a soft inclusion enlarged the region of increased wall stress compared with either alone. In some configurations, the rigid inclusion reduced peak stress at the edge of the soft inclusion but simultaneously increased peak stress at the edge of the rigid inclusion and increased the size of the region affected. These findings suggest that the presence of a calcium deposit creates local increases in failure stress, and, depending on relative position to any neighboring lipid pools, it may increase peak stress and the plaque area at risk of mechanical failure. PMID:19542489

Hoshino, Tetsuya; Chow, Lori A.; Hsu, Jeffrey J.; Perlowski, Alice A.; Abedin, Moeen; Tobis, Jonathan; Tintut, Yin; Mal, Ajit K.; Klug, William S.; Demer, Linda L.



Photolichenoid plaques with associated vitiliginous pigmentary changes.  


A 49-year-old man with advanced HIV/AIDS on anti-retroviral therapy (HAART) and trimethoprim-sulfamethoxazole (TMP-SMX) presented with a several-month history of pruritic, erythematous, lichenified papules that coalesced into hyperkeratotic plaques on the trunk and extremities in a sun-exposed distribution. He shortly thereafter developed a progressive depigmentation over more than 80 percent of his body surface area. A biopsy specimen of an erythematous plaque on the trunk showed a superficial and mid-dermal infiltrate of lymphocytes with eosinophils, most consistent with either chronic lichenoid drug eruption or atypical lymphoproliferative disorder (ACLD) of HIV. The patient's lichenoid skin disease has persisted despite discontinuation of TMP-SMX, although it has improved partially with administration of topical glucocorticoids and acitretin. His depigmentation has continued to progress. We discuss the overlapping diagnostic entities which may be comprised by this patient's clinical disease, and highlight a unique presentation of the complex interaction between HIV infection and the skin. PMID:22031639

Tran, Kathleen; Hartman, Rachael; Tzu, Julia; Meehan, Shane; Sanders, Scott E; Pomeranz, Miriam Keltz; Sanchez, Miguel



Early second trimester uterine scar rupture.  


Spontaneous uterine scar rupture can be lethal in pregnant women. A spontaneous uterine scar rupture in the early mid-trimester is rare and difficult to diagnose. This is a case of a 30-year-old woman (G2P1L1) at 19 weeks of gestation and having undergone a previous caesarean section presented with acute abdomen in shock. Laparotomy revealed a uterine scar rupture, which was resutured after evacuation of products of conception. This case merits that the uterine rupture should be considered as a differential diagnosis in pregnant women presenting with acute abdomen. In this case, although there was uterine rupture in the second trimester and a complete placental separation, fetus was alive which is quite unusual in patients presenting with rupture uterus. PMID:24326433

Bharatnur, Sunanda; Hebbar, Shripad; Shyamala, G



[Rupture of the diaphragm of late manifestation].  


Twenty one cases of delayed diagnosis of ruptured diaphragm caused by closed trauma are reported: 14 on the left side and 7 on the right side. The clinical signs and the modes of presentation are non-specific. Although the history of thoraco-abdominal trauma and the chest x-ray are sufficient to establish the diagnosis of rupture of the left hemidiaphragm, they can only suggest the diagnosis in cases of righ-sided rupture. The mechanism of rupture is more often due to sudden reflex contraction of the diaphragm against a closed glottis than to excessive abdominal pressure caused by the trauma. Diaphragmatic rupture due to closed trauma causes large tears exposing the patient to a low risk of strangulation of intestinal structures in contrast with ruptures due to a penetrating injury, which causes small tears. The diaphragmatic domes must be systematically explored during laparotomy or thoracotomy performed for thoraco-abdominal trauma. PMID:2189337

Lenot, B; Bellenot, F; Regnard, J F; Dartevelle, P; Rojas-Miranda, A; Levasseur, P



Delayed aortic rupture following perforating trauma  

PubMed Central

The immediate death rate for aortic rupture caused by pointed and sharp-edged instruments is very high; however, delayed aortic rupture following the trauma is rarely reported. A patient who had an upper abdominal stab wound was sent to our hospital, and an emergency exploratory laparotomy was performed. No traumatic aortic rupture was found at that time. However, on the fifth day after surgery, aortic rupture occurred, and a large retroperitoneal hematoma was formed. The patient eventually died. Aortic rupture was confirmed by a second emergency exploratory laparotomy and the autopsy. The information from exploratory laparotomies, post-operative observations and treatments, medical imaging reports, and reasons for delayed aortic rupture, as well as the underlying pathophysiological processes, are discussed in this case report.

Yang, Xuefei; Xia, Ligang



Investigation of cryogenic rupture disc design  

NASA Technical Reports Server (NTRS)

Rupture disc designs of both the active (command actuated) and passive (pressure ruptured) types were evaluated for performance characteristics at cryogenic temperatures and for capability to operate in a variety of cryogens, including gaseous and liquid fluorine. The test results, coupled with information from literature and industry searches, were used to establish a statement of design criteria and recommended practices for application of rupture discs to cryogenic rocket propellant feed and vent systems.

Keough, J. B.; Oldland, A. H.



Free cholesterol in atherosclerotic plaques: where does it come from?  

Microsoft Academic Search

Purpose of review Free cholesterol in plaques is an emerging contributing factor to lesion instability and, until recently, apoptosis of lipid-laden macrophages was considered the major source of free cholesterol. The validity of this concept is beginning to be challenged since there is recent evidence of erythrocyte membrane-derived cholesterol in plaques. Therefore, intraplaque hemorrhage may not be a passive event,

Frank D. Kolodgie; Allen P. Burke; Gaku Nakazawa; Qi Cheng; Xin Xu; Renu Virmani



Characterization of bacteriophage communities and CRISPR profiles from dental plaque  

PubMed Central

Background Dental plaque is home to a diverse and complex community of bacteria, but has generally been believed to be inhabited by relatively few viruses. We sampled the saliva and dental plaque from 4 healthy human subjects to determine whether plaque was populated by viral communities, and whether there were differences in viral communities specific to subject or sample type. Results We found that the plaque was inhabited by a community of bacteriophage whose membership was mostly subject-specific. There was a significant proportion of viral homologues shared between plaque and salivary viromes within each subject, suggesting that some oral viruses were present in both sites. We also characterized Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) in oral streptococci, as their profiles provide clues to the viruses that oral bacteria may be able to counteract. While there were some CRISPR spacers specific to each sample type, many more were shared across sites and were highly subject specific. Many CRISPR spacers matched viruses present in plaque, suggesting that the evolution of CRISPR loci may have been specific to plaque-derived viruses. Conclusions Our findings of subject specificity to both plaque-derived viruses and CRISPR profiles suggest that human viral ecology may be highly personalized. PMID:24981669



Dietary trans fatty acids and composition of human atheromatous plaques  

Microsoft Academic Search

Summary. Dietary fatty acids are incorporated into atheromatous plaques mainly in the form of cholesterol esters. Physicochemical properties of the plaque (e. g. mechanical strength) depend on its fatty acid composition. Trans isomers of unsaturated fatty acids (TFA) are known to reduce the availability of fatty acid precursors for the synthesis of anticoagulant PG 1 and PG 3 prostaglandins. The

Ewa Stachowska; Barbara Do??gowska; Dariusz Chlubek; Teresa Weso?owska; Kazimierz Ciechanowski; Piotr Gutowski; Halina Szumi?owicz; Rados?aw Turowski



Plaque Assay for Q Fever and Scrub Typhus Rickettsiae  

PubMed Central

The plaque assay procedure developed for spotted fever and typhus group rickettsiae is also appropriate for scrub typhus and Q fever rickettsiae. The plaque titers of suspensions of Rickettsia tsutsugamushi and Coxiella burnetii compared favorably with end points obtained by titrations in mice. Images PMID:4989539

McDade, Joseph E.; Gerone, Peter J.



MR microscopy of human amyloid-? deposits: characterization of parenchymal amyloid, diffuse plaques, and vascular amyloid.  


Cerebral deposits of amyloid-? peptides (A?) form the neuropathological hallmarks of Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). In the brain, A? can aggregate as insoluble fibrils present in amyloid plaques and vascular amyloid, or as diffuse plaques consisting of mainly non-fibrillar A?. Previously, magnetic resonance imaging (MRI) has been shown to be capable of detecting individual amyloid plaques, not only via the associated iron, but also A? itself has been suggested to be responsible for a decrease in the image intensity. In this current study we aim to investigate the MRI properties of the different cerebral A? deposits including diffuse plaques and vascular amyloid. Postmortem 60-?m-thick brain sections of AD, CAA, and Down's syndrome patients, known to contain A?, were studied. High resolution T2*- and T2-weighted MRI scans and quantitative relaxation maps were acquired using a microcoil on a Bruker 9.4T MRI system. Specific MRI characteristics of each type of A? deposit were examined by co-registration of the MRI with Congo Red and A?-immunostainings of the same sections. Our results show that only fibrillar A?, present in both vascular and parenchymal amyloid, induced a significant change in T2* and T2 values. However, signal changes were not as consistent for all of the vessels affected by CAA, irrespective of possible dyshoric changes. In contrast, the non-fibrillar diffuse plaques did not create any detectable MRI signal changes. These findings are relevant for the interpretation and further development of (quantitative) MRI methods for the detection and follow-up of AD and CAA. PMID:23340037

Nabuurs, Rob J A; Natté, Remco; de Ronde, Fenna M; Hegeman-Kleinn, Ingrid; Dijkstra, Jouke; van Duinen, Sjoerd G; Webb, Andrew G; Rozemuller, Annemieke J; van Buchem, Mark A; van der Weerd, Louise



Neck curve polynomials in neck rupture model  

SciTech Connect

The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of {sup 280}X{sub 90} with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.

Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul [Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung 40132 (Indonesia)



Spontaneous rupture of uterine leiomyoma during labour.  


Uterine rupture in labour requires an emergency caesarean section. In women with a uterine scar, either from gynaecological surgery or from a previous caesarean section, it is well documented that the risk of rupture is higher than in those without. Spontaneous uterine rupture in a uterus with fibroids during pregnancy or labour is extremely rare. We present a case of a 33-year-old, unbooked pregnant woman from Nigeria who had a uterine rupture secondary to fibroids. She required an emergency caesarean section in labour. The fibroids were not removed. Her baby was born alive and in good condition and she made an uneventful recovery. PMID:25199188

Ramskill, Nikki; Hameed, Aisha; Beebeejaun, Yusuf



Automated coronary CT angiography plaque-lumen segmentation  

NASA Astrophysics Data System (ADS)

We are investigating the feasibility of a computer-aided detection (CAD) system to assist radiologists in diagnosing coronary artery disease in ECG gated cardiac multi-detector CT scans having calcified plaque. Coronary artery stenosis analysis is challenging if calcified plaque or the iodinated blood pool hides viable lumen. The research described herein provides an improved presentation to the radiologist by removing obscuring calcified plaque and blood pool. The algorithm derives a Gaussian estimate of the point spread function (PSF) of the scanner responsible for plaque blooming by fitting measured CTA image profiles. An initial estimate of the extent of calcified plaque is obtained from the image evidence using a simple threshold. The Gaussian PSF estimate is then convolved with the initial plaque estimate to obtain an estimate of the extent of the blooming artifact and this plaque blooming image is subtracted from the CT image to obtain an image largely free of obscuring plaque. In a separate step, the obscuring blood pool is suppressed using morphological operations and adaptive region growing. After processing by our algorithm, we are able to project the segmented plaque-free lumen to form synthetic angiograms free from obstruction. We can also analyze the coronary arteries with vessel tracking and centerline extraction to produce cross sectional images for measuring lumen stenosis. As an additional aid to radiologists, we also produce plots of calcified plaque and lumen cross-sectional area along selected blood vessels. The method was validated using digital phantoms and actual patient data, including in one case, a validation against the results of a catheter angiogram.

Cline, Harvey E.; Krishnan, Karthik; Napel, Sandy; Rubin, Geoffrey D.; Turner, Wesley D.; Avila, Ricardo S.



Association of the platelet GPIIb/IIIa polymorphism with atherosclerotic plaque morphology. The Atherosclerosis Risk in Communities (ARIC) Study  

PubMed Central

Objectives Platelet activation and aggregation play an important role in the pathogenesis of cardiovascular disease. We examined the association of a single nucleotide polymorphism (SNP) in the GPIIIa platelet glycoprotein (Leu33Pro) with carotid artery plaque morphology and with expression of platelet markers using data from the Atherosclerosis Risk in Communities (ARIC) Carotid MRI study. Methods The study sample consisted of 1,202 Caucasian members of the ARIC study cohort recruited in 2004-2005 to participate in the Carotid MRI Substudy under stratified sampling based on maximum carotid artery wall thickness. The Leu33Pro polymorphism was identified as SNP rs5918 in the ITGB3 gene. Plaque visualization was accomplished with contrast enhanced MRI examination of the thickest segment of the carotid artery. Expression of platelet markers was measured using fasting whole blood flow cytometry. Results This cross-sectional analysis based on age and gender adjusted weighted linear regression models suggests that those homozygous for the Leu33Pro risk allele (C) have decreased mean and minimum fibrous cap thickness. We did not observe differences in plaque lipid volume or maximum carotid artery wall thickness across SNP rs5918 genotypes. Carriers of the Leu33Pro polymorphism, as compared to major allele homozygotes, had greater percent of platelets expressing P-selectin, a platelet glycoprotein indicating activation status. Prevalent coronary heart disease did not affect estimates of fibrous cap thickness or of platelet activation. Conclusion Our results suggest that individuals with Leu33Pro polymorphism of the GPIIIa glycoprotein may be predisposed to increased risk of atherosclerotic plaque rupture. PMID:21353223

Kucharska-Newton, Anna M.; Monda, Keri L.; Campbell, Stephen; Bradshaw, Patrick T.; Wagenknecht, Lynne E.; Boerwinkle, Eric; Wasserman, Bruce A.; Heiss, Gerardo



MMP?1 and MMP?9 regulate epidermal growth factor?dependent collagen loss in human carotid plaque smooth muscle cells  

PubMed Central

Abstract Mechanisms underlying the rupture of atherosclerotic plaque, a crucial factor in the development of myocardial infarction and stroke, are not well defined. Here, we examined the role of epidermal growth factor (EGF)?mediated matrix metalloproteinases (MMP) on the stability of interstitial collagens in vascular smooth muscle cells (VSMCs) isolated from carotid endarterectomy tissues of symptomatic and asymptomatic patients with carotid stenosis. VSMCs isolated from the carotid plaques of both asymptomatic and symptomatic patients were treated with EGF. The MMP?9 activity was quantified by gelatin zymography and the analysis of mRNA transcripts and protein for MMP?9, MMP?1, EGFR and collagen types I, Col I(?1) and collagen type III, Col III(?1) were analyzed by qPCR and immunofluorescence, respectively. The effect of EGF treatment to increase MMP?9 activity and mRNA transcripts for MMP?9, MMP?1, and EGFR and to decrease mRNA transcripts for Col I(?1) and Col III(?1) was threefold to fourfold greater in VSMCs isolated from the carotid plaques of symptomatic than asymptomatic patients. Inhibitors of EGFR (AG1478) and a small molecule inhibitor of MMP?9 decreased the MMP9 expression and upregulated Col I(?1) and Col III(?1) in EGF?treated VSMCs of both groups. Additionally, the magnitude in decreased MMP?9 mRNA and increased Col I(?1) and Col III(?1) due to knockdown of MMP?9 gene with siRNA in EGF?treated VSMCs was significantly greater in the symptomatic group than the asymptomatic group. Thus, a selective blockade of both EGFR and MMP?9 may be a novel strategy and a promising target for stabilizing vulnerable plaques in patients with carotid stenosis. PMID:24744893

Rao, Velidi H.; Kansal, Vikash; Stoupa, Samantha; Agrawal, Devendra K.



Imaging of atherosclerotic plaques in obesity: excessive fat accumulation, plaque progression and vulnerability.  


Obesity is becoming a major health issue in the world due to sedentary lifestyles and increasing intake of Western diets. Obesity is associated with metabolic abnormalities and atherosclerotic cardiovascular diseases. Adipose tissue has been increasingly considered to play a critical role in inducing metabolic disturbances and promoting atherogenesis. Arterial wall imaging permits direct visualization of atheroma burden in various vascular beds. In addition, recent advances in imaging technology help characterize components, microstructures and functional features of atherosclerotic plaques. These imaging modalities have contributed to elucidating factors associated with atherosclerosis in obese patients. Also, it provides opportunities to evaluate the effect of novel therapies on plaques in the setting of obesity. The findings of recent imaging studies and the clinical implications will be reviewed. PMID:25355677

Kataoka, Yu; Nicholls, Stephen J



Relationship between Watershed Infarcts and Recent Intra Plaque Haemorrhage in Carotid Atherosclerotic Plaque  

PubMed Central

Objective Watershed infarcts (WSI) are thought to result from hemodynamic mechanism, but studies have suggested that microemboli from unstable carotid plaques may distribute preferentially in watershed areas, i.e., between two cerebral arterial territories. Intraplaque haemorrhage (IPH) is an emerging marker of plaque instability and microembolic activity. We assessed the association between WSI and IPH in patients with recently symptomatic moderate carotid stenosis. Methods and Results We selected 65 patients with symptomatic moderate (median NASCET degree of stenosis?=?31%) carotid stenosis and brain infarct on Diffusion-Weighted Imaging (DWI) on Magnetic Resonance Imaging (MRI) from a multicentre prospective study. Fourteen (22%) had WSI (cortical, n?=?8; internal, n?=?4; cortical and internal, n?=?2). Patients with WSI were more likely to have IPH than those without WSI although the difference was not significant (50% vs. 31%, OR?=?2.19; 95% CI, 0.66–7.29; P?=?0.20). After adjustment for degree of stenosis, age and gender, the results remained unchanged. Conclusion About one in fifth of brain infarcts occurring in patients with moderate carotid stenosis were distributed in watershed areas. Albeit not significant, an association between IPH - more generally plaque component - and WSI, still remains possible. PMID:25272160

Isabel, Clothilde; Lecler, Augustin; Turc, Guillaume; Naggara, Olivier; Schmitt, Emmanuelle; Belkacem, Samia; Oppenheim, Catherine; Touze, Emmanuel



Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data.  


In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T(1)-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was -1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60-0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena. PMID:22617149

Sakellarios, Antonis I; Stefanou, Kostas; Siogkas, Panagiotis; Tsakanikas, Vasilis D; Bourantas, Christos V; Athanasiou, Lambros; Exarchos, Themis P; Fotiou, Evangelos; Naka, Katerina K; Papafaklis, Michail I; Patterson, Andrew J; Young, Victoria E L; Gillard, Jonathan H; Michalis, Lampros K; Fotiadis, Dimitrios I



Modeling Ruptures and Tsunamis That May Follow Event of September 12  

NASA Astrophysics Data System (ADS)

The seismic series of the 12-13 September near the Padang/Bengkulu region in Western Sumatra, Indonesia, emerged to, but did not rupture the three locked patches at the subduction plate interface as recently derived from geodetic and paleogeodetic studies (Chlieh et al., 2007), likely increasing probability of the next giant earthquake off Padang. Future earthquake, when rupturing all of the three locked patches, may reach a magnitude of about M=9 and repeat giant historical event of 1797 and partly that of 1833 followed by severe tsunamis. We have modeled possible earthquake and tsunami scenarios assuming future ruptures coinciding with each of the presently locked patches. Our modeling is performed in a framework of the currently developed German- Indonesian Tsunami Early Warning System (GITEWS). Resulting tsunami wave height in Padang is very sensitive to the location of the ruptured patch. The shallow patch under the Siberut island and the deep patch just off Padang, both result in M=8.4 earthquakes. However, the latter rupture would result in considerably shorter arrival time and in more than 5 times higher run-up in Padang. We show that GPS stations at islands and at Padang can be used to estimate rupture parameters and to predict tsunami heights just after the earthquake. Our modeling also demonstrates that historical records about the 1797 tsunami are more consistent with the simultaneous rupturing of both the shallow and deep patches off Padang.

Babeyko, A. Y.; Sobolev, S. V.; Harig, S.; Androsov, A.



Longitudinal ruptures of polyester knitted vascular prostheses  

Microsoft Academic Search

Aim: The purpose of the study was the characterization of a type of rupture occurring on warp-knitted polyester vascular prostheses. Materials and Methods: We studied 20 cases of warp-knitted polyester vascular prostheses that were explanted from humans that showed a longitudinal rupture as a part of a collaborative retrieval program. All the prostheses were immediately fixed in a 10% formaldehyde

Nabil Chakfe; Gunnar Riepe; Florence Dieval; Jean-Francois Le Magnen; Lu Wang; Elisabeth Urban; Marc Beaufigeau; Bernard Durand; Herbert Imig; Jean-Georges Kretz



Ruptured liver abscess in a neonate.  


We report a rare case of 17-day-old neonate, diagnosed to have ruptured liver abscess secondary to Methicillin-resistant Staphylococcal aureus infection. The child presented with septicemia and abdominal distension. On exploration, there was pyoperitoneum with ruptured liver abscess. PMID:22382113

Jain, Prashant; Mishra, Ashwani; Agarawal, Vyom



Dynamic Interface Rupture in Extremely Heterogeneous Media  

Microsoft Academic Search

Fracture experiments of monolithic brittle materials usually show the maximum speed of smooth rupture at some 30 % of the relevant shear wave speed. This experimental maximum rupture speed is by far lower than those predicted by theories and inferred from inversions of seismograms, and some seismic inversions (e.g., the 1979 Imperial Valley, 1992 Landers, 1999 Izmit, 2001 the central

K. Uenishi; K. Tsuji



Rupture Velocity of Plane Strain Shear Cracks  

Microsoft Academic Search

Propagation of plane strain shear cracks is calculated numerically by using finite difference equations with second-order accuracy. The rupture model, in which stress drops gradually as slip increases, combines two different rupture criteria: (1) slip begins at a finite stress level; (2) finite energy is absorbed per unit area as the crack advances. Solutions for this model are nonsingular. In

D. J. Andrews



Collagenolytic Activity of Dental Plaque Associated with Periodontal Pathology  

PubMed Central

Certain dental plaques, removed from sites of gingival and periodontal pathology in mentally retarded, institutionalized individuals, when incubated in phosphate buffer with Achilles tendon collagen, gave rise to an increase in ninhydrin-positive material. These plaques, while showing great variability, released significantly more ninhydrin-positive material per milligram of plaque (wet weight) than did either the endogenous or heat-treated controls. Certain plaques could also break down soluble, tritiated, labeled collagen isolated from the calvaria of chicken embryos. Bacteroides melaninogenicus and Clostridia histolyticum were found in plaques by either fluorescent antibody or cultural methods. C. histolyticum, when detected, accounted for about 0.01 to 0.1% of the bacteria in plaque. A conspicuous isolate from some plaques was a Bacillus species which rapidly liquefied gelatin. Cell-free supernatants of this organism were able to degrade about 50 to 70% of the soluble collagen when incubated at 36 C. C. histolyticum ATCC 8034 caused an 80% degradation of the collagen under the same conditions of incubation. The Bacillus strains were facultative, could ferment glucose, reduced nitrate to nitrite, and were catalase, indole, and urease negative. The limited taxonomic information for the isolates is compatible with the description given for Bacillus cereus. PMID:4361294

Loesche, W. J.; Paunio, K. U.; Woolfolk, M. P.; Hockett, R. N.



Senile plaque neurites in Alzheimer disease accumulate amyloid precursor protein.  

PubMed Central

Senile plaques are polymorphous beta-amyloid protein deposits found in the brain in Alzheimer disease and normal aging. This beta-amyloid protein is derived from a larger precursor molecule of which neurons are the principal producers in brain. We found that amyloid precursor protein (APP)-immunoreactive neurites were involved in senile plaques and that only a subset of these neurites showed markers for the abnormal filaments characteristic of neurofibrillary pathology. In the neocortex of nondemented individuals with senile plaques but spared of neurofibrillary pathology, dystrophic neurites in senile plaques showed only APP accumulation. In contrast, in the brains of Alzheimer patients, virtually all APP-immunoreactive neurites also showed immunoreactivity with ubiquitin, tau, and phosphorylated neurofilaments. The presence of tau and neurofilament epitopes in dystrophic neurites in senile plaques was correlated with the extent of neurofibrillary pathology in the surrounding brain tissue. Accumulation of APP and the formation of neurofibrillary pathology in senile plaque neurites are therefore distinct phenomena. Our findings suggest that APP accumulation in senile plaque neurites occurs prior to tau accumulation and is therefore more closely related to appearance of neuritic dystrophy. Images PMID:1652752

Cras, P; Kawai, M; Lowery, D; Gonzalez-DeWhitt, P; Greenberg, B; Perry, G



Spontaneous splenic rupture in a hemodialysis patient.  


Spontaneous splenic rupture (SSR) in a patient undergoing hemodialysis has been described as an extremely rare and potentially fatal complication. We report here spontaneous splenic rupture in a 52-year-old woman undergoing regular hemodialysis for end-stage renal disease (ESRD). She complained of colicky abdominal pain in the left upper quadrant area and dizziness when she assumed an upright posture. Her vital signs revealed low blood pressure and tachycardia, which was suggestive of hypovolemic shock. Abdomen CT scan showed splenic hematoma and hemoperitoneum. However, she had no history of any event triggering the splenic rupture. An exploratory laparotomy showed a ruptured spleen and an emergency splenectomy was performed. We suggest that spontaneous spleen rupture may be attributed to uremic coagulopathy and heparin-induced coagulopathy. PMID:15988818

Kim, Hyun Jung; Lee, Gyeong Won; Park, Dong Jun; Lee, Jong Deog; Chang, Se Ho



COMS eye plaque brachytherapy dosimetric sensitivity to source photon energy and seed design.  


This study explores the influence of source photon energy on eye plaque brachytherapy dose distributions for a 16 mm COMS plaque filled with (103)Pd, (125)I, or (131)Cs sources or monoenergetic photon emissions ranging from 12 keV to 100 keV. Dose distributions were similarly created for all permutations of three common brachytherapy seed designs. Within this range, sources with average energy ?22 keV may reduce dose to the opposite eye wall by more than a factor of 2 while maintaining tolerable proximal sclera doses when prescribing to depths of 9 mm or less. Current commercially-available brachytherapy sources can exhibit up to 15% relative dosimetric sensitivity to seed design at regions within the eye. PMID:23728350

Gagne, Nolan L; Rivard, Mark J



MRI plaque imaging reveals high-risk carotid plaques especially in diabetic patients irrespective of the degree of stenosis  

PubMed Central

Background Plaque imaging based on magnetic resonance imaging (MRI) represents a new modality for risk assessment in atherosclerosis. It allows classification of carotid plaques in high-risk and low-risk lesion types (I-VIII). Type 2 diabetes mellitus (DM 2) represents a known risk factor for atherosclerosis, but its specific influence on plaque vulnerability is not fully understood. This study investigates whether MRI-plaque imaging can reveal differences in carotid plaque features of diabetic patients compared to nondiabetics. Methods 191 patients with moderate to high-grade carotid artery stenosis were enrolled after written informed consent was obtained. Each patient underwent MRI-plaque imaging using a 1.5-T scanner with phased-array carotid coils. The carotid plaques were classified as lesion types I-VIII according to the MRI-modified AHA criteria. For 36 patients histology data was available. Results Eleven patients were excluded because of insufficient MR-image quality. DM 2 was diagnosed in 51 patients (28.3%). Concordance between histology and MRI-classification was 91.7% (33/36) and showed a Cohen's kappa value of 0.81 with a 95% CI of 0.98-1.15. MRI-defined high-risk lesion types were overrepresented in diabetic patients (n = 29; 56.8%). Multiple logistic regression analysis revealed association between DM 2 and MRI-defined high-risk lesion types (OR 2.59; 95% CI [1.15-5.81]), independent of the degree of stenosis. Conclusion DM 2 seems to represent a predictor for the development of vulnerable carotid plaques irrespective of the degree of stenosis and other risk factors. MRI-plaque imaging represents a new tool for risk stratification of diabetic patients. See Commentary: PMID:21118504



Dynamic Interface Rupture in Extremely Heterogeneous Media  

NASA Astrophysics Data System (ADS)

Fracture experiments of monolithic brittle materials usually show the maximum speed of smooth rupture at some 30 % of the relevant shear wave speed. This experimental maximum rupture speed is by far lower than those predicted by theories and inferred from inversions of seismograms, and some seismic inversions (e.g., the 1979 Imperial Valley, 1992 Landers, 1999 Izmit, 2001 the central Kunlunshan and 2002 Denali earthquakes) even suggest the existence of supershear rupture speeds (i.e., rupture propagating faster than the relevant shear wave). Recently, Uenishi et al. ( SSJ Fall Meeting, 2004, 2005; AGU Fall Meeting, 2006) experimentally investigated dynamic fracture in monolithic hyperelastic materials under static mode-§ loading conditions with relatively high crack-parallel stresses. Using a high-speed digital video camera system, they showed that cracks may propagate supersonically even in homogeneous materials. However, the exact mechanism for rupture nucleation and the transition of a nucleated rupture from sub-Rayleigh to super-shear rupture speed has not been identified yet. In this contribution, we further develop our experimental system and investigate dynamic fracture in extremely heterogeneous media, consisting of thin fluid and solid films: Inside a wire frame (50mm high, 50mm wide), a flat soap film contacts a flat thin solid plastic film (20mm high, 20mm wide), under static tensile loading conditions. The rupture (crack), initiated at a point, propagates subsonically in the linear elastic fluid film (see e.g., Uenishi et al., SSJ Fall Meeting, 2006, for the dynamic rupture in monolithic fluid films). When the circular rupture front reaches the interface, the rupture advances along the interface and then it is "diffracted" at the two corners of the interface. We record the rupture propagation process utilizing our high-speed digital video camera at a frame rate of 20 ?s (20×10-6s). The observed results show that interface rupture propagation may accelerate (or even decelerate) and the dynamic rupture behavior is very sensitive to the geometry of the interface between the two films: (1) When the subsonic rupture front reaches the first rectangular corner, it accelerates around the corner and then advances supersonically along the interface; and (2) when the supersonic interface rupture front approaches the second corner (obtuse with respect to the rupture front in fluid), it bifurcates for a short period (400 ?s): the first branch unexpectedly expands rather straight into the bulk and the second one propagates along the interface at a lower speed; At a later stage, again unexpectedly, the first branched crack decelerates significantly in the bulk and the two cracks eventually merge into a single crack. The overall behavior is - in some sense - similar to that of the oblique shock and Prandtl- Meyer expansion waves in fluid mechanics, and it might give new insights not only into the question of high rupture speeds of natural earthquakes but also into the generation mechanism of tsunamis.

Uenishi, K.; Tsuji, K.



Advances in mechanisms, imaging and management of the unstable plaque.  


Post-mortem observations demonstrated that plaque fissure was the final event leading to coronary thrombosis and occlusion in about two-thirds of cases of sudden coronary death. Plaques prone to fissure have, therefore, been defined "vulnerable plaques" and are identified by specific anatomic features including thin inflamed fibrous cap, large lipidic core and positive remodeling. Accordingly, elegant imaging modalities have been developed in order to identify this "holy grail". However, the results of prognostic studies based on the identification of vulnerable plaques have not been encouraging because of the low positive predictive value for major cardiovascular events. This observation is not surprising as the pathogenesis of acute coronary syndromes is complex and multifactorial. In this review we propose a pathogenetic classification of acute coronary syndromes in the attempt to identify homogeneous groups of patients with a common mechanism of coronary instability which can be identified by using specific biomarkers and imaging techniques, and become a specific therapeutic target. PMID:24530781

Niccoli, Giampaolo; Liuzzo, Giovanna; Montone, Rocco A; Crea, Filippo




Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW TO THE SOUTHEAST. MEMORIAL WITH BRONZE PLAQUE IN HONOR OF KELLER, MARKS THE CENTER OF THE BRIDGE. - Keller Memorial Bridge, Spanning Tennessee River at U.S. Highway 31, Decatur, Morgan County, AL


Detection of Atherosclerotic Coronary Plaques by Fluorescence Lifetime Imaging Angioscopy  

E-print Network

the potential of a FLIM angioscopy system to detect and differentiate coronary atherosclerotic plaques ex-vivo into several groups including thin, fibrotic, lipid-laden, thick-cap fibroatheroma (FA), and fibrocalcified. Samples were extracted post-mortem weekly...

Thomas, Patrick A.




Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. DETAIL VIEW, LOOKING WEST, SHOWING STONE PLAQUE INSCRIBED 'USRA, 1936' LOCATED IN EAST ELEVATION (tHIS PHOTOGRAPH IS FOGGED) - Spring Lake Bridge, Spanning Bob Barnes Branch at County Road No. 36D, Belleville, Yell County, AR


Radiobiology for eye plaque brachytherapy and evaluation of implant duration and radionuclide choice using an objective function  

SciTech Connect

Purpose: Clinical optimization of Collaborative Ocular Melanoma Study (COMS) eye plaque brachytherapy is currently limited to tumor coverage, consensus prescription dosage, and dose calculations to ocular structures. The biologically effective dose (BED) of temporary brachytherapy treatments is a function of both chosen radionuclide R and implant duration T. This study endeavored to evaluate BED delivered to the tumor volume and surrounding ocular structures as a function of plaque position P, prescription dose, R, and T. Methods: Plaque-heterogeneity-corrected dose distributions were generated with MCNP5 for the range of currently available COMS plaques loaded with sources using three available low-energy radionuclides. These physical dose distributions were imported into the PINNACLE{sup 3} treatment planning system using the TG-43 hybrid technique and used to generate dose volume histograms for a T = 7 day implant within a reference eye geometry including the ciliary body, cornea, eyelid, foveola, lacrimal gland, lens, optic disc, optic nerve, retina, and tumor at eight standard treatment positions. The equation of Dale and Jones was employed to create biologically effective dose volume histograms (BEDVHs), allowing for BED volumetric analysis of all ROIs. Isobiologically effective prescription doses were calculated for T = 5 days down to 0.01 days, with BEDVHs subsequently generated for all ROIs using correspondingly reduced prescription doses. Objective functions were created to evaluate the BEDVHs as a function of R and T. These objective functions are mathematically accessible and sufficiently general to be applied to temporary or permanent brachytherapy implants for a variety of disease sites. Results: Reducing T from 7 to 0.01 days for a 10 mm plaque produced an average BED benefit of 26%, 20%, and 17% for {sup 103}Pd, {sup 125}I, and {sup 131}Cs, respectively, for all P; 16 and 22 mm plaque results were more position-dependent. {sup 103}Pd produced a 16%-35% BED benefit over {sup 125}I, whereas {sup 131}Cs produced a 3%-7% BED detriment, independent of P, T, and plaque size. Additionally, corresponding organ at risk physical doses were lowest using {sup 103}Pd in all circumstances. Conclusions: The results suggest that shorter implant durations may correlate with more favorable outcomes compared to 7 day implants when treating small or medium intraocular lesions. The data also indicate that implant duration may be safely reduced if the prescription physical dose is likewise diminished and that {sup 103}Pd offers a substantial radiobiological benefit over {sup 125}I and {sup 131}Cs irrespective of plaque position, implant duration, and tumor size.

Gagne, Nolan L.; Leonard, Kara L.; Rivard, Mark J. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)



Transforming growth factor-?1 in plaque morphea  

PubMed Central

Introduction Morphea (localized scleroderma) is a rare cutaneous disease characterized by skin fibrosis of unknown pathogenesis. Transforming growth factor-? (TGF-?) is a potent profibrotic factor. The role of TGF-? in morphea remains unclear. Aim The goal of this study was to estimate the expression level of TGF-?1 in skin and peripheral blood mononuclear cells as well as the plasma levels of TGF-?1 in plaque morphea (MEP). Material and methods The study involved 20 MEP patients. Three control groups were involved: 1 – plasma: 36 healthy volunteers; 2 – PBMC: 47 healthy volunteers; 3 – skin biopsies: 13 samples collected during mastectomy (breast cancer was not skin involved). The analysis of TGF-?1 plasma levels was performed with the use an adequate ELISA kit, while real-time polymerase chain reaction was employed for the expression of TGF-?1 in peripheral blood mononuclear cells (PBMC) and skin. Results In our study we have not detected differences in TGF-? 1 expression in PBMC, skin, nor in plasma levels of TGF-?1 between MEP patients and healthy controls, regardless of disease activity and its duration. Conclusions The results of our study contradict the claim of the substantial role of TGF-?1 in the most common morphea subtype – MEP. PMID:24493995

Kowalczyk, Michal J.; Szramka-Pawlak, Beata; Gornowicz-Porowska, Justyna; Szewczyk, Aleksandra; Silny, Wojciech; Molinska-Glura, Marta; Olewicz-Gawlik, Anna; Zaba, Ryszard; Pazdrowski, Jakub; Hrycaj, Pawel



Age at intracranial aneurysm rupture among generations  

PubMed Central

Background: Previous studies have reported intracranial aneurysm (IA) occurring at young ages in subsequent generations. These studies did not correct for duration of follow-up. Second-generation members who would have their ruptured IA late in life may not be detected due to shorter follow-up time than the first generation. We examined families in which ruptured IA occurred in two consecutive generations for the hypothesis that the second generation (F1) was more likely to have a rupture at a younger age than the older generation (F0). Methods: The Familial Intracranial Aneurysm (FIA) Study is a multicenter, international study recruiting families of ruptured and unruptured IA. All available family members are interviewed. Cox proportional hazards regression models and Kaplan-Meier curves were used to examine differences by generation. Results: Although we found that the F1 generation was more likely to have an aneurysm rupture at a younger age than the F0 generation, we found that this was largely because of a lack of follow-up time in the F1 generation. The F1 generation had 50% the rupture rate of the prior generation. When analyzed by Kaplan-Meier curves, we found a tendency to have a slightly later rupture rate in the F1 generation once time to follow-up was included in the analysis model. Conclusions: Families of ruptured intracranial aneurysm (IA) do not appear to demonstrate “anticipation.” Our finding suggests that genetic epidemiology of ruptured IA should examine all types of variations such as single base-pair changes, deletions, insertions, and other variations that do not demonstrate anticipation. GLOSSARY FIA = familial intracranial aneurysm; IA = intracranial aneurysm; SAH = subarachnoid hemorrhage. PMID:19237697

Woo, D; Hornung, R; Sauerbeck, L; Brown, R; Meissner, I; Huston, J; Foroud, T; Broderick, J



Toward tsunami early warning system in Indonesia by using rapid rupture durations estimation  

SciTech Connect

Indonesia has Indonesian Tsunami Early Warning System (Ina-TEWS) since 2008. The Ina-TEWS has used automatic processing on hypocenter; Mwp, Mw (mB) and Mj. If earthquake occurred in Ocean, depth < 70 km and magnitude > 7, then Ina-TEWS announce early warning that the earthquake can generate tsunami. However, the announcement of the Ina-TEWS is still not accuracy. Purposes of this research are to estimate earthquake rupture duration of large Indonesia earthquakes that occurred in Indian Ocean, Java, Timor sea, Banda sea, Arafura sea and Pasific ocean. We analyzed at least 330 vertical seismogram recorded by IRIS-DMC network using a direct procedure for rapid assessment of earthquake tsunami potential using simple measures on P-wave vertical seismograms on the velocity records, and the likelihood that the high-frequency, apparent rupture duration, T{sub dur}. T{sub dur} can be related to the critical parameters rupture length (L), depth (z), and shear modulus ({mu}) while T{sub dur} may be related to wide (W), slip (D), z or {mu}. Our analysis shows that the rupture duration has a stronger influence to generate tsunami than Mw and depth. The rupture duration gives more information on tsunami impact, Mo/{mu}, depth and size than Mw and other currently used discriminants. We show more information which known from the rupture durations. The longer rupture duration, the shallower source of the earthquake. For rupture duration greater than 50 s, the depth less than 50 km, Mw greater than 7, the longer rupture length, because T{sub dur} is proportional L and greater Mo/{mu}. Because Mo/{mu} is proportional L. So, with rupture duration information can be known information of the four parameters. We also suggest that tsunami potential is not directly related to the faulting type of source and for events that have rupture duration greater than 50 s, the earthquakes generated tsunami. With available real-time seismogram data, rapid calculation, rupture duration discriminant can be completed within 4-5 min after an earthquake occurs and thus can aid in effective, accuracy and reliable tsunami early warning for Indonesia region.

Madlazim [Physics Department, Faculty Mathematics and Sciences of Surabaya State University (UNESA) Jl. Ketintang, Surabaya 60231 (Indonesia)



Therapeutic Modifications to the Mineral Ion Composition of Dental Plaque  

Microsoft Academic Search

A mouth rinse containing calcium, phosphate, fluoride, urea and monofluorophosphate was used 12 times over 3 days by 15 young adults. The concentration of acid-extractable fluoride in 4-day-old plaque rose from 8.4 to 560 ng\\/mg dry weight. Plaque calcium increased from 4.1 to 42.5 ?g\\/mg and phosphate from 3.9 to 22.7 ?g\\/ mg. The ions are fixed in a form

E. I. F. Pearce



Spectral CT imaging of vulnerable plaque with two independent biomarkers  

Microsoft Academic Search

The purpose of this paper is to investigate the feasibility of a novel four-material decomposition technique for assessing the vulnerability of plaque with two contrast materials spectral computer tomography (CT) using two independent markers: plaque's inflammation and spotty calcification. A simulation study was conducted using an energy-sensitive photon-counting detector for k-edge imaging of the coronary arteries. In addition to detecting

Pavlo Baturin; Yahya Alivov; Sabee Molloi



Detail of plaque beneath column on the south parapet at ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of plaque beneath column on the south parapet at the west end of the bridge. The plaque reads ?1914; Mayor E.J. Drussel; Councilmen E.S. Henry, E.F. Hogan, R.P. Lamdin, C.F. Ross, J.H. Shuppert; Leonard & Day, Engineers; C.H. Gildersleeve, Builder.? - First Street Bridge, Spanning Napa River at First Street between Soscol Avenue & Juarez Street, Napa, Napa County, CA


Effects of dietary flaxseed on atherosclerotic plaque regression.  


Dietary flaxseed can retard the progression of atherosclerotic plaques. However, it remains unclear whether these antiatherogenic effects extend to plaque regression. In the present study, the therapeutic potential of dietary flaxseed on atherosclerotic plaque regression and vascular contractile function was evaluated using a novel rabbit model. Rabbits were randomly assigned to receive either a regular diet for 12 wk (group I) or a 1% cholesterol-supplemented diet for 4 wk followed by a regular diet for 8 wk (group II). The remaining experimental animals were treated as in group II but were fed for an additional 14 wk with either a regular diet (group III) or a 10% flaxseed-supplemented diet (group IV). Animals in group II showed clear evidence of plaque growth stabilization. Their vessels also exhibited significantly lower norepinephrine-induced contraction and an impaired relaxation response to acetylcholine compared with animals in group I. Dietary flaxseed supplementation resulted in a significant ?40% reduction in plaque formation (P = 0.033). Animals in both groups II and III displayed improved contraction and endothelium-dependent vessel relaxation. Dietary flaxseed is a valuable strategy to accelerate the regression of atherosclerotic plaques; however, flaxseed intervention did not demonstrate a clear beneficial effect on the vessel contractile response and endothelium-dependent vasorelaxation. PMID:23585134

Francis, Andrew A; Deniset, Justin F; Austria, Jose A; LaValleé, Renee K; Maddaford, Graham G; Hedley, Thomas E; Dibrov, Elena; Pierce, Grant N



Improved plaque assays for Rickettsia prowazekii in Vero 76 cells.  

PubMed Central

Typhus group rickettsiae, including Rickettsia prowazekii and R. typhi, produce visible plaques on primary chick embryo fibroblasts and low-passage mouse embryo fibroblasts but do not form reproducible plaques on continuous cell culture lines. We tested medium overlay modifications for plaque formation of typhus group rickettsiae on the continuous fibroblast cell line Vero76. A procedure involving primary overlay with medium at pH 6.8, which was followed 2 to 3 days later with secondary overlay at neutral pH containing 1 microgram of emetine per ml and 20 micrograms of NaF per ml, resulted in visible plaques at 7 to 10 days postinfection. A single-step procedure involving overlay with medium containing 50 ng of dextran sulfate per ml also resulted in plaque formation within 8 days postinfection. These assays represent reproducible and inexpensive methods for evaluating the infectious titers of typhus group rickettsiae, cloning single plaque isolates, and testing the susceptibilities of rickettsiae to antibiotics. PMID:8818887

Policastro, P F; Peacock, M G; Hackstadt, T



Phenotypic modulation of macrophages in response to plaque lipids  

PubMed Central

Purpose of review The accumulation of macrophages in the vascular wall is a hallmark of atherosclerosis. The biological properties of atherosclerotic plaque macrophages determine lesion size, composition and stability. In atherosclerotic plaques, macrophages encounter a microenvironment that is comprised of a variety of lipid oxidation products, each of which has diverse biological effects. In this review, we summarize recent advances in our understanding of the effects of plaque lipids on macrophage phenotypic polarization. Recent findings Atherosclerotic lesions in mice and in humans contain various macrophage phenotypes, which play different roles in mediating inflammation, the clearance of dead cells, and possibly resolution. Macrophages alter their phenotype and biological function in response to plaque lipids through the upregulation of specific sets of genes. Interaction of oxidized lipids with pattern recognition receptors and activation of the inflammasome by cholesterol crystals drive macrophages towards an inflammatory M1 phenotype. A new phenotype, Mox, develops when oxidized phospholipids activate stress response genes via Nrf2. Other lipid mediators such as nitrosylated-fatty acids and omega-3 fatty acid-derived products polarize plaque macrophages towards anti-inflammatory and proresolving phenotypes. Summary A deeper understanding of how lipids that accumulate in atherosclerotic plaques affect macrophage phenotype and function and thus atherosclerotic lesion development and stability will help to devise novel strategies for intervention. PMID:21841486

Adamson, Samantha; Leitinger, Norbert



Automated tissue characterization of in vivo atherosclerotic plaques by intravascular optical coherence tomography images  

PubMed Central

Intravascular optical coherence tomography (IVOCT) is rapidly becoming the method of choice for the in vivo investigation of coronary artery disease. While IVOCT visualizes atherosclerotic plaques with a resolution <20µm, image analysis in terms of tissue composition is currently performed by a time-consuming manual procedure based on the qualitative interpretation of image features. We illustrate an algorithm for the automated and systematic characterization of IVOCT atherosclerotic tissue. The proposed method consists in a supervised classification of image pixels according to textural features combined with the estimated value of the optical attenuation coefficient. IVOCT images of 64 plaques, from 49 in vivo IVOCT data sets, constituted the algorithm’s training and testing data sets. Validation was obtained by comparing automated analysis results to the manual assessment of atherosclerotic plaques. An overall pixel-wise accuracy of 81.5% with a classification feasibility of 76.5% and per-class accuracy of 89.5%, 72.1% and 79.5% for fibrotic, calcified and lipid-rich tissue respectively, was found. Moreover, measured optical properties were in agreement with previous results reported in literature. As such, an algorithm for automated tissue characterization was developed and validated using in vivo human data, suggesting that it can be applied to clinical IVOCT data. This might be an important step towards the integration of IVOCT in cardiovascular research and routine clinical practice. PMID:23847728

Ughi, Giovanni Jacopo; Adriaenssens, Tom; Sinnaeve, Peter; Desmet, Walter; D'hooge, Jan



From Isolated Sites to Complete Ruptures; the Next Hurdle for Paleoseismology on the Southern San Andreas Fault  

NASA Astrophysics Data System (ADS)

At least fifteen sites on the southern San Andreas fault provide some information on the timing or displacement of recent earthquakes. While the data are often sufficient to determine mean recurrence intervals, the time interval since the last earthquake, and crude estimates of magnitude, the wide range of ages, recurrence intervals and displacements seen from site to site currently preclude any simple correlation of site specific information into compelling ruptures. During the past 1300-1400 years at least twelve ruptures, averaging 200-300 km in length, are required to explain the data. These twelve events could be similar-length, quasi-periodic earthquakes rupturing the northern 2/3 or the southern half of the fault south of Parkfield with substantial overlap. In this scenario 1857 was a typical northern rupture and the 1812 event was anomalously short. Another 12-rupture scenario includes five complete ruptures of the 530 km Southern San Andreas, six approximately 100 km infilling events in the Mojave to San Bernardino region, like 1812, and the 1857 event that was an anomalously short rupture that should have completed the fault. As more ruptures are added to explain the data, an increasingly random distribution of recurrence intervals and lengths with highly variable overlap becomes possible. The existing age data favor more, smaller ruptures because of the imperfect overlap of ages from multiple sites. The displacement data generally favor larger ruptures spanning sites despite the relatively poor overlap of ages, perhaps suggesting problems with existing age control. Advances in determining the probability of rupture length given displacement, the creative use of sites that provide only event count or total displacement in an interval of time spanning multiple earthquakes, better C-14 dating accounting for the multiple sources of carbon on paleoseismic samples, and investment of time and effort into a few keystone sites with robust results promise to greatly clarify this picture in the next 3-5 years.

Weldon, R. J.; Biasi, G. P.; Fumal, T. E.; Scharer, K. M.



pH Heterogeneity of human and rabbit atherosclerotic plaques; a new insight into detection of vulnerable plaque  

Microsoft Academic Search

Background: Atherosclerotic plaques are heterogeneous with respect to inflammation, calcification, vascularity, oxygen, and temperature. We hypothesized that they also vary in pH and measured pH in living human carotid endarterectomized atherosclerotic plaques (CEA), Watanabe heritable hyperlipidemic (WHHL) rabbit aortas and human umbilical arteries (HUA). Methods and results: We measured pH of CEA of 48 patients, nine WHHL rabbit aortas and

Morteza Naghavi; Reji John; Sameh Naguib; Mir Said Siadaty; Roxana Grasu; K. C Kurian; W. Barry van Winkle; Babs Soller; Silvio Litovsky; Mohammad Madjid; James T Willerson; Ward Casscells



[Bilateral rupture of the Achilles tendon--an unusual occurrence].  


We present the clinical case of a sixty-four-year-old man with bilateral spontaneous rupture of the Achilles tendon having a multiple disseminated oesophagus carcinoma. After immobilisation due to metastases of the 2nd lumbar vertebra, there was a spontaneous, painless rupture of the Achilles tendon while the patient was mobilised wearing a Hohmann spine brace. Afterwards we carried out a thorough case history with the help of clinical examination, sonographic and magnetic resonance imaging. The bilateral rupture has been treated conservatively with the Adipromed Shoe. With regard to the 2nd lumbar vertebra fracture and metastases, a Hohmann spine brace was given to the patient. Because of the described circumstances, no surgery had been carried out. Furthermore, the patient experienced much more independence and an improved quality of life in his last couple of months. Surgery would have not been recommended and could have caused the complete immobilisation and loss of patient's quality of life. With this case report we would like to point out the consequences of an unwise therapeutic decision to a patient who only has a few more months to live. This case report is discussed with regard to the possible aetiopathology and the current literature. PMID:16991068

Schikora, N; Delank, K-S; Gärtner, J; Eysel, P



Describing Soils: Calibration Tool for Teaching Soil Rupture Resistance  

ERIC Educational Resources Information Center

Rupture resistance is a measure of the strength of a soil to withstand an applied stress or resist deformation. In soil survey, during routine soil descriptions, rupture resistance is described for each horizon or layer in the soil profile. The lower portion of the rupture resistance classes are assigned based on rupture between thumb and…

Seybold, C. A.; Harms, D. S.; Grossman, R. B.



Supershear Rupture Propagation in Homogeneous, Monolithic Media: Experimental Observations  

Microsoft Academic Search

The rupture speeds obtained by fracture experiments of monolithic brittle materials are usually by far lower than those predicted by theories and inferred from inversions of seismograms: Some seismic inversions even suggest the existence of supershear rupture speeds (i.e., rupture propagating faster than the relevant shear wave). Exceptionally, a few laboratory experiments of dynamic rupture on pre-cut interfaces do indicate

K. Uenishi



Ruptured uterus: an ongoing tragedy of motherhood.  


This study aimed to determine the frequency of ruptured uterus, possible aetiologic factors, foetomaternal out come and changes in obstetric care proposed to reduce this catastrophy. From September 1994 to September 1999 in Dhaka Medical College Hospital 39,782 deliveries occurred. All delivery records were reviewed and rupture uterus cases were identified. The result was compared with studies carried out in home and abroad. During the five years period among 39,782 deliveries 424 cases were of rupture uterus with a frequency of 1/93 deliveries. Eighty three percent rupture occurred in intact uterus and 17% occurred in uteri scarred by caesarian section. Common contributing factors were -prolonged/obstructed labour, grand multiparity, injudicious use of uterine stimulants, mismanaged labour by traditional birth attendant, delayed referral to well equipped centre, poor communication, poverty and ignorance. PMID:11942487

Khanam, R A; Khatun, M



Management of traumatic aortic rupture.  


A traumatic thoracic aortic injury is a severe and life-threatening clinical entity. Although largely fatal; if untreated, these injuries are amenable to surgical repair if appropriately diagnosed. Therefore, early triage of this condition is critically important. Unfortunately, aortic injuries rarely occur in isolation, and there has been no good cutoff value to help select the appropriate surgical strategy. Algorithms for the both diagnosis and treatment of traumatic thoracic aortic injury have undergone changes in recent years. There have been several case reports, retrospective series and registry data describing the treatment of patients with traumatic thoracic aortic rupture using endovascular treatment. Endovascular treatment is a less-invasive management option for polytraumatized patients. Because it is less invasive, without the need for thoracotomy or the use of heparin, endovascular repair can be performed even in acutely injured patients, without the risk of destabilizing pulmonary, head or abdominal traumatic lesions. Long-term follow-up especially in young patients is necessary after endovascular treatment. PMID:23338596

Watanabe, Ken-ichi; Fukuda, Ikuo; Asari, Yasushi



Rupture of lenticulostriate artery aneurysms.  


The authors report on 3 rare cases of ruptured lenticulostriate artery (LSA) aneurysms that were heralded by deep cerebral hematomas. The hematomas were unilateral in 2 cases and bilateral in 1; in the bilateral case, only a single LSA aneurysm could be identified on the right side of the brain. Because of their small size (? 2 mm), fusiform aspect, and deep location within the brain, all of the aneurysms were treated conservatively. There was no hemorrhage recurrence, and follow-up angiography demonstrated spontaneous thrombosis in 2 of the 3 cases. The clinical course was favorable in 2 of the 3 patients. The course in the patient with the bilateral hematoma was marked by an ischemic event after the initial episode, resulting in an aggravation of deficits. The cause of this second event was uncertain. Because our knowledge about the natural history of LSA aneurysms is incomplete, there is no consensus concerning a therapeutic strategy. The authors' experience in 3 reported cases leads them to think that a conservative approach involving close angiographic monitoring may be proposed as first-line treatment. If the monitored aneurysm then persists or grows in size, its occlusion should be considered. Nonetheless, other studies are needed to further strengthen the legitimacy of this strategy. PMID:24053505

Heck, Olivier; Anxionnat, René; Lacour, Jean-Christophe; Derelle, Anne-Laure; Ducrocq, Xavier; Richard, Sébastien; Bracard, Serge



Successful management of postinfarction ventricular septal rupture  

PubMed Central

Ventricular septal rupture is a rare but devastating complication of acute myocardial infarction. Especially in patients with cardiogenic shock, right ventricular dysfunction or an inferior infarct mortality is very high. We present a case in which an 83-year-old patient survived rupture of the ventricular septum complicating an inferior myocardial infarction. Unlike most patients his haemodynamic status did not deteriorate and delayed elective surgical repair was carried out successfully. ImagesFigure 1Figure 2

Swinkels, B.M.; Peters, R.H.J.; van den Brink, A.



Spontaneous rupture of tubal leiomyoma causing haemoperitoneum.  


Leiomyomas are benign tumours that usually originate from the genital tract organs, particularly from the uterus. Spontaneous rupture of leiomyomas is a relatively rare condition. Herein, we report a 70 years old lady who was admitted through the emergency room with sudden abdominal pain. A ruptured mass originating from the fallopian tube, causing haemoperitoneum was revealed at laparotomy. Pathological examination revealed cellular leiomyoma. PMID:24906284

Ozkan, Zeynep; Gonen, Ayse Nur; Emir, Seyfi; Yazar, Fatih Mehmet; Gul, Evrim; Artas, Zeynep Dogan; Aslan, Ozgen; Artas, Hakan



Association between Variations in Coagulation System Genes and Carotid Plaque  

PubMed Central

Objective Genetic variation in coagulation and fibrinolysis may affect the development of subclinical atherosclerosis modifying the risk of stroke and cardiovascular disease. However, data on the relationship between subclinical atherosclerosis and genes involved in the coagulation system are sparse. The objective of this study is to examine the association between single nucleotide polymorphisms (SNPs) in coagulation system genes and subclinical carotid plaque phenotypes. Methods From the Genetic Determinants of Subclinical Carotid Disease study, 287 Dominicans were examined for carotid plaque presence, thickness, and surface irregularity by high-resolution B-mode carotid ultrasound. Logistic regression was used to test for association between 101 SNPs in 23 coagulation system genes and plaque phenotypes while controlling for age, sex, smoking, hypertension, dyslipidemia, and diabetes. Within gene haplotypes and interactions between genes were examined. A follow-up of SNPs in moderate to high (r2>0.25) linkage disequilibrium (LD) with those implicated in the discovery analysis (p?0.01) was performed in an independent sample of 301 Dominicans. Results The prevalence of carotid plaque (47% discovery; 46% follow-up) as well as the mean age (65±8 discovery; 65±9 follow-up) of the participants was similar in both datasets. Two genes (vWF and THBS1) were associated (p?0.01) with plaque size and surface irregularity. In followup, 5 SNPs in vWF were associated (p?0.05) with plaque size. SERPINE1 was an additional gene of interest in the haplotype and interaction analyses. Conclusions Variation in the vWF, THBS1, and SERPINE1 gene may play an important role in the pathogenesis of atherosclerotic plaque. PMID:22982001

Della-Morte, David; Beecham, Ashley; Dong, Chuanhui; Wang, Liyong; McClendon, Mark S.; Gardener, Hannah; Blanton, Susan H.; Sacco, Ralph L.; Rundek, Tatjana



Angiotensin Receptor Blockade With Candesartan Attenuates Atherosclerosis, Plaque Disruption, and Macrophage Accumulation Within the Plaque in a Rabbit Model  

PubMed Central

Background Little is known about whether direct angiotensin receptor blockade can reduce atherosclerosis and plaque disruption. This study evaluated the effect of angiotensin receptor blockade on both the development of atherosclerosis and the disruption of plaque in a modified Constantinides animal model. Methods and Results Twenty-eight New Zealand White rabbits underwent aortic balloon injury followed by a 1% cholesterol diet for 8 weeks. Thirteen rabbits received candesartan at 0.5 mg · kg?1 · d?1 beginning 2 days before aortic balloon injury and continued for the total 8 weeks of the cholesterol diet. The rabbits were then pharmacologically triggered and humanely killed, and their aortas were analyzed. The degree of atherosclerosis was determined by intima-media ratio of the infrarenal portion of the aorta. The frequency of intra-aortic thrombosis, a measure of plaque disruption, and the percentages of macrophage area and collagen-staining area of the plaque were determined. Candesartan-treated rabbits had less atherosclerosis (intima-media infrarenal aorta ratio of 1.18±0.08 versus 1.57±0.08 [mean±SEM] for the placebo group, P<0.001); fewer thrombi (3 of 13 versus 11 of 15; P<0.05); lower percentage area of macrophages to total plaque (18.8±2.7% versus 27±2.5%, P<0.05); and higher collagen to total plaque area (45±3% versus 35±2%, P<0.01). Conclusions These results demonstrate that angiotensin receptor blockade attenuates the degree of atherosclerosis and reduces both plaque disruption and macrophage accumulation while increasing collagen deposition in the aortas of this animal model. PMID:15451796

Perez, Alexandra S.; Nasser, Imad; Stewart, Robert; Vaidya, Anand; Al Ammary, Fawaz; Schmidt, Ben; Horowitz, Gary; Dolgoff, Jennifer; Hamilton, James; Quist, William C.



Low Copper and High Manganese Levels in Prion Protein Plaques  

PubMed Central

Accumulation of aggregates rich in an abnormally folded form of the prion protein characterize the neurodegeneration caused by transmissible spongiform encephalopathies (TSEs). The molecular triggers of plaque formation and neurodegeneration remain unknown, but analyses of TSE-infected brain homogenates and preparations enriched for abnormal prion protein suggest that reduced levels of copper and increased levels of manganese are associated with disease. The objectives of this study were to: (1) assess copper and manganese levels in healthy and TSE-infected Syrian hamster brain homogenates; (2) determine if the distribution of these metals can be mapped in TSE-infected brain tissue using X-ray photoelectron emission microscopy (X-PEEM) with synchrotron radiation; and (3) use X-PEEM to assess the relative amounts of copper and manganese in prion plaques in situ. In agreement with studies of other TSEs and species, we found reduced brain levels of copper and increased levels of manganese associated with disease in our hamster model. We also found that the in situ levels of these metals in brainstem were sufficient to image by X-PEEM. Using immunolabeled prion plaques in directly adjacent tissue sections to identify regions to image by X-PEEM, we found a statistically significant relationship of copper-manganese dysregulation in prion plaques: copper was depleted whereas manganese was enriched. These data provide evidence for prion plaques altering local transition metal distribution in the TSE-infected central nervous system. PMID:23435237

Johnson, Christopher J.; Gilbert, P.U.P.A.; Abrecht, Mike; Baldwin, Katherine L.; Russell, Robin E.; Pedersen, Joel A.; Aiken, Judd M.; McKenzie, Debbie



Infliximab in the treatment of plaque type psoriasis  

PubMed Central

Psoriasis is a chronic and immunomediated skin disease characterized by erythematous scaly plaques. Psoriasis affects approximately 1% to 3% of the Caucasian population. Tumor necrosis factor alpha (TNF-?) is a proinflammatory cytokine that plays a critical role in the pathogenesis of psoriasis. Infliximab is an anti-TNF-? drug widely used for the treatment of plaque type psoriasis and psoriatic arthritis. Controlled clinical trials demonstrated that infliximab is characterized by a high degree of clinical response in moderate to severe plaque psoriasis. Moreover infliximab showed rapid efficacy in nail psoriasis which represents a therapeutic challenge for dermatologists and a relevant source of distress for patients with plaque psoriasis. This anti-TNF-? has an encouraging safety profile, especially as long as physicians are watchful in prevention and early diagnosis of infections and infuse reactions. The efficacy, tolerability and safety profiles suggest infliximab as a suitable anti-psoriatic drug in the long-term treatment of a chronic disease such as plaque-type psoriasis. PMID:21436966

Saraceno, Rosita; Saggini, Andrea; Pietroleonardo, Lucia; Chimenti, Sergio



Uniaxial tensile testing approaches for characterisation of atherosclerotic plaques.  


The pathological changes associated with the development of atherosclerotic plaques within arterial vessels result in significant alterations to the mechanical properties of the diseased arterial wall. There are several methods available to characterise the mechanical behaviour of atherosclerotic plaque tissue, and it is the aim of this paper to review the use of uniaxial mechanical testing. In the case of atherosclerotic plaques, there are nine studies that employ uniaxial testing to characterise mechanical behaviour. A primary concern regarding this limited cohort of published studies is the wide range of testing techniques that are employed. These differing techniques have resulted in a large variance in the reported data making comparison of the mechanical behaviour of plaques from different vasculatures, and even the same vasculature, difficult and sometimes impossible. In order to address this issue, this paper proposes a more standardised protocol for uniaxial testing of diseased arterial tissue that allows for better comparisons and firmer conclusions to be drawn between studies. To develop such a protocol, this paper reviews the acquisition and storage of the tissue, the testing approaches, the post-processing techniques and the stress-strain measures employed by each of the nine studies. Future trends are also outlined to establish the role that uniaxial testing can play in the future of arterial plaque mechanical characterisation. PMID:24508324

Walsh, M T; Cunnane, E M; Mulvihill, J J; Akyildiz, A C; Gijsen, F J H; Holzapfel, G A



[Endemic pleural plaques and environmental factors (author's transl)].  


In an agricultural town in Burgenland (Austria) we found an increased prevalence of pleural plaques. These calcifying thickenings of the pleura are related to minimal asbestos exposure such as is mesothelioma, but they cannot be regarded as a precancerosis. The increased occurrence of pleural plaques in this town of nearly 3500 inhabitants (in which during 1916 to 1945 asbestos was mined) we first found at the chest x-ray archives of a pulmologic hospital, then by mass radiography and blind comparison with control groups. A photofluoroscopy of 300 persons yielded 16 cases with definite pleural plaques (5.3%) among which were 4 cases with suspected asbestosis and another 14 cases with uncertain pleural plaques (4.7%). The 600 control persons showed no such radiological changes. Interviews wich persons detected for pleural plaques at mass radiography gave no indication that they had occupational asbestos exposure. But asbestos was detected in the soil of vineyards and in the dust of the houses. Asbestos was also detectable in the atmospheric dust by x-ray diffraction and scanning electron microscopic techniques. PMID:749422

Neuberger, M; Gründorfer, W; Haider, M; Königshofer, R; Müller, H W; Raber, A; Riedmüller, G; Schwaighofer, B



Laser speckle imaging of atherosclerotic plaques through optical fiber bundles.  


Laser speckle imaging (LSI), a new technique that measures an index of plaque viscoelasticity, has been investigated recently to characterize atherosclerotic plaques. These prior studies demonstrated the diagnostic potential of LSI for detecting high-risk plaques and were conducted ex vivo. To conduct intracoronary LSI in vivo, the laser speckle pattern must be transmitted from the coronary wall to the image detector in the presence of cardiac motion. Small-diameter, flexible optical fiber bundles, similar to those used in coronary angioscopy, may be incorporated into an intravascular catheter for this purpose. A key challenge is that laser speckle is influenced by inter-fiber leakage of light, which may be exacerbated during bundle motion. In this study, we tested the capability of optical fiber bundles to transmit laser speckle patterns obtained from atherosclerotic plaques and evaluated the influence of motion on the diagnostic accuracy of fiber bundle-based LSI. Time-varying helium-neon laser speckle images of aortic plaques were obtained while cyclically moving the flexible length of the bundle to mimic coronary motion. Our results show that leached fiber bundles may reliably transmit laser speckle images in the presence of cardiac motion, providing a viable option to conduct intracoronary LSI. PMID:19021396

Nadkarni, Seemantini K; Bouma, Brett E; Yelin, Dvir; Gulati, Amneet; Tearney, Guillermo J



Rayleigh mixture model for plaque characterization in intravascular ultrasound.  


Vulnerable plaques are the major cause of carotid and coronary vascular problems, such as heart attack or stroke. A correct modeling of plaque echomorphology and composition can help the identification of such lesions. The Rayleigh distribution is widely used to describe (nearly) homogeneous areas in ultrasound images. Since plaques may contain tissues with heterogeneous regions, more complex distributions depending on multiple parameters are usually needed, such as Rice, K or Nakagami distributions. In such cases, the problem formulation becomes more complex, and the optimization procedure to estimate the plaque echomorphology is more difficult. Here, we propose to model the tissue echomorphology by means of a mixture of Rayleigh distributions, known as the Rayleigh mixture model (RMM). The problem formulation is still simple, but its ability to describe complex textural patterns is very powerful. In this paper, we present a method for the automatic estimation of the RMM mixture parameters by means of the expectation maximization algorithm, which aims at characterizing tissue echomorphology in ultrasound (US). The performance of the proposed model is evaluated with a database of in vitro intravascular US cases. We show that the mixture coefficients and Rayleigh parameters explicitly derived from the mixture model are able to accurately describe different plaque types and to significantly improve the characterization performance of an already existing methodology. PMID:21245004

Seabra, José C; Ciompi, Francesco; Pujol, Oriol; Mauri, Josepa; Radeva, Petia; Sanches, João



Radiolabeled probes for imaging Alzheimer’s plaques  

NASA Astrophysics Data System (ADS)

Alzheimer's disease (AD) is a debilitating disease characterized by the presence of extra-cellular plaques and intra-cellular neurofibrillary tangles (NFTs) in the brain. The major protein component of these plaques is beta amyloid peptide (A?), a 40-42 amino acid peptide cleaved from amyloid precursor protein (APP) by ?-secretase and a putative ?-secretase. We radioiodinated quinoline derivatives (clioquinol and oxine) and evaluated them as potential amyloid imaging agents based on their ability to cross the blood brain barrier (BBB) and on their selectivity to metal binding sites on amyloid plaques. The uptake of theses tracers in the brains of normal swiss-webster mice was rapid and so was the clearance. Selectivity was demonstrated by higher binding to AD brain homogenates compared to normal brain. Autoradiographic studies demonstrated the localization of the tracers in the plaque regions of the AD brain sections as well as in liver tissue with amyloidosis. Further optimization and evaluations would likely lead to development of these molecules as AD plaque imaging agents.

Kulkarni, P. V.; Arora, V.; Roney, A. C.; White, C.; Bennett, M.; Antich, P. P.; Bonte, F. J.



Plaque Assay of Rickettsiae in a Mammalian Cell Line  

PubMed Central

Clear-cut and repeatable plaque assays were obtained for three rickettsiae of the spotted fever group (Rickettsia rickettsi, R. conori, and R. montana) in Vero cells used in a manner similar to that for arboviruses. In addition, three typhus group agents (R. typhi, R. canada, R. prowazeki) induced plaques in these cells. In preliminary tests Coxiella burneti (Nine Mile strain) failed to produce plaques. Comparable results were obtained in plastic flasks and plastic culture trays incubated in ambient air with or without addition of N-2-hydroxyethyl-piperazine-N?-2-ethanesulfinic acid buffer. Larger and more well defined R. rickettsi plaques were produced when cultures were overlaid with Leibovitz (L15) medium than with either medium 199 or Eagle medium. Phosphate-buffered saline containing bovine plasma albumin (fraction V), in contrast to brain heart infusion broth, as a diluent for preparing inocula consistently permitted development of larger and more numerous plaques with three agents: R. rickettsi, R. conori, and R. montana. When R. rickettsi and R. typhi were assayed in parallel in primary chicken embryo cultures and Vero cells, comparable results were obtained, but with R. canada results in Vero cells were superior. In contrast, R. prowazeki produced inconsistent results in Vero cells. Images PMID:4208640

Cory, J.; Yunker, C. E.; Ormsbee, R. A.; Peacock, M.; Meibos, H.; Tallent, G.



Blood Chemical Abnormalities in Cattle with Ruptured Bladders and Ruptured Urethras  

PubMed Central

A study was undertaken to determine the blood chemical variables and compare changes that occurred with ruptured bladders and ruptured urethras in steers and yearling bulls. The fatality rates were 10.5% in steers with ruptured urethras and 50.8% in steers with ruptured bladders. Both groups had significantly decreased serum sodium and chloride values and significantly increased serum creatinine, blood urea nitrogen, and plasma protein concentrations compared to the normal group. Steers with ruptured bladders were more dehydrated, had significantly lower serum sodium and chloride values and had significantly higher blood urea nitrogen concentrations than steers with ruptured urethras. The combination of a decreased serum sodium, a decreased serum chloride, and a decreased ratio of serum phosphate to blood urea nitrogen occurred consistently within the ruptured bladder group. Of the variables examined, serum phosphate was the best prognostic indicator in the steers with ruptured bladders as all of the steers that died had a serum phosphate in excess of 2.9 mmol/L. The fluid and electrolyte changes are discussed. PMID:17422206

Donecker, J. M.; Bellamy, J. E. C.



On the potential of a new IVUS elasticity modulus imaging approach for detecting vulnerable atherosclerotic coronary plaques: in vitro vessel phantom study  

NASA Astrophysics Data System (ADS)

Peak cap stress amplitude is recognized as a good indicator of vulnerable plaque (VP) rupture. However, such stress evaluation strongly relies on a precise, but still lacking, knowledge of the mechanical properties exhibited by the plaque components. As a first response to this limitation, our group recently developed, in a previous theoretical study, an original approach, called iMOD (imaging modulography), which reconstructs elasticity maps (or modulograms) of atheroma plaques from the estimation of strain fields. In the present in vitro experimental study, conducted on polyvinyl alcohol cryogel arterial phantoms, we investigate the benefit of coupling the iMOD procedure with the acquisition of intravascular ultrasound (IVUS) measurements for detection of VP. Our results show that the combined iMOD-IVUS strategy: (1) successfully detected and quantified soft inclusion contours with high positive predictive and sensitivity values of 89.7 ± 3.9% and 81.5 ± 8.8%, respectively, (2) estimated reasonably cap thicknesses larger than ~300 µm, but underestimated thinner caps, and (3) quantified satisfactorily Young's modulus of hard medium (mean value of 109.7 ± 23.7 kPa instead of 145.4 ± 31.8 kPa), but overestimated the stiffness of soft inclusions (mean Young`s moduli of 31.4 ± 9.7 kPa instead of 17.6 ± 3.4 kPa). All together, these results demonstrate a promising benefit of the new iMOD-IVUS clinical imaging method for in vivo VP detection.

Le Floc'h, Simon; Cloutier, Guy; Finet, Gérard; Tracqui, Philippe; Pettigrew, Roderic I.; Ohayon, Jacques



Basal plate plaque: a novel organising placental thrombotic process.  


In contrast to thrombi and haematomas at other body sites, thrombi in the placental intervillous space are not traditionally known to undergo organisation. This report presents 11 examples of a form of organising thrombotic process that develops as a plaque on the foetal aspect of the basal plate. Originally identified in the placenta of a foetus showing severe intrauterine growth restriction, further examples of this lesion, which we term a 'basal plate plaque', show a spectrum of placental involvement. Small lesions appear to occur at points of localised stasis at the basal plate (eg, at edges of anchoring villi or in small basal plate depressions). Large areas of involvement, as seen in the original case, may be pathological markers of more generalised disturbances in placental circulation or of hypercoagulability in the intervillous space. Large basal plate plaques may therefore prove to be diagnostically significant and should be reported. PMID:21252255

Fitzgerald, Brendan; Shannon, Patrick; Kingdom, John; Keating, Sarah



Recurrence Characteristics of 'Full Rupture' Earthquakes  

NASA Astrophysics Data System (ADS)

A prime goal in earthquake geology is to identify the recurrence characteristics of full rupture earthquakes (earthquakes that rupture the full down-dip extend of the seismogenic zone and potentially beyond it) along a given fault. Paleoseismology and tectonic geomorphology enable to extend the seismic record by centuries or millennia --for events that are sufficiently large to disrupt the earth surface. Unfortunately, long records are rare and it is generally difficult to make statistically meaningful statements on recurrence characteristics. Furthermore, the paleoseismic and geomorphic records may also contain partial rupture earthquakes (events that may rupture ground surface but do not activate the full seismogenic width) and by that the masking signal of the full rupture events (as I will show in my presentation, those partial rupture events exhibit different recurrence characteristics than the full rupture events). Physics-based earthquake simulators provide the means to study the long-term behavior of a (simulated) fault with respect to the implemented boundary conditions (e.g., fault geometry, loading conditions, frictional behavior). Here, I present a numerical study on earthquake recurrence characteristics as a function of fault geometric roughness (considered a proxy for fault maturity) and by that as a function of fault interaction and connectivity. Focus was on magnitude-frequency distribution and fault segmentation as a function of roughness. I find that bimodality in magnitude frequency relation --the largest earthquakes occurring more frequently than anticipated from the Gutenberg-Richter relation-- is tightly linked to the structural maturity of a fault. Bimodal seismic behavior and maximum earthquake size increases as fault roughness decreases. Furthermore, the variability of large earthquake rupture characteristics of a given fault decreases with structural maturation and major earthquakes along spatially isolated faults exhibit inherent periodicity. While slip at a point along a fault is variable per se, variability becomes increasingly systematic as the fault matures. Based on my results and supported by paleoseismic data, I propose that previously presented earthquake recurrence models (uniform slip-, and characteristic earthquake model) generalize the seismic behavior of faults with different structural age and fault-system complexity and are characterized by alternating single-segment and multi-segment rupture probability.

Zielke, O.



Caring for people with carotid artery rupture.  


In the second of three articles, the authors discuss the care of people with carotid artery rupture. Carotid artery rupture is a potentially fatal condition that requires swift action on the part of the nurse who is present. The size of the rupture and the prognosis for the individual patient determines whether or not active resuscitation is undertaken. The multi-professional team should decide, in advance of an impending rupture, on the optimum plan of care. Calm, careful explanations should be given to patients and relatives and the decision regarding resuscitation should be recorded in the patient's notes. In the event of unforeseen circumstances where a rupture occurs, an active nursing care plan should be instituted and care taken to keep relatives well informed. The patient's airway should be kept clear through the use of suctioning, inflation of tracheostomy tube cuff and correct positioning. Sedative drugs and palliative care may subsequently be necessary. Support and help should be given to all who witness or are involved in the care of these patients. PMID:16415744

Frawley, Theresa; Begley, Cecily M


Bifurcation analysis of a model for atherosclerotic plaque evolution  

NASA Astrophysics Data System (ADS)

We analyze two ordinary differential equation (ODE) models for atherosclerosis. The ODE models describe long time evolution of plaques in arteries. We show how the dynamics of the first atherosclerosis model (model A) can be understood using codimension-two bifurcation analysis. The Low-Density Lipoprotein (LDL) intake parameter (d) is the first control parameter and the second control parameter is either taken to be the conversion rate of macrophages (b) or the wall shear stress (?). Our analysis reveals that in both cases a Bogdanov-Takens (BT) point acts as an organizing center. The bifurcation diagrams are calculated partly analytically and to a large extent numerically using AUTO07 and MATCONT. The bifurcation curves show that the concentration of LDL in the plaque as well as the monocyte and the macrophage concentrations exhibit oscillations for a certain range of values of the control parameters. Moreover, we find that there are threshold values for both the cholesterol intake rate dcrit and the conversion rate of the macrophages bcrit, which depend on the values of other parameters, above which the plaque volume increases with time. It is found that larger conversion rates of macrophages lower the threshold value of cholesterol intake and vice versa. We further argue that the dynamics for model A can still be discerned in the second model (model B) in which the slow evolution of the radius of the artery is coupled self-consistently to changes in the plaque volume. The very slow evolution of the radius of the artery compared to the other processes makes it possible to use a slow manifold approximation to study the dynamics in this case. We find that in this case the model predicts that the concentrations of the plaque constituents may go through a period of oscillations before the radius of the artery will start to decrease. These oscillations hence act as a precursor for the reduction of the artery radius by plaque growth.

Bulelzai, M. A. K.; Dubbeldam, J. L. A.; Meijer, H. G. E.



Method of making a light weight battery plaque  

NASA Technical Reports Server (NTRS)

A nickel plaque which may be coated with a suitable metal or compound to make an electrode for a fuel cell or battery is fabricated by directing nickel sensitizer, catalyst and plating solutions through a porous plastic substrate in the order named and at prescribed temperatures and flow rates. A boride compound dissolved in the plating solution decreases the electrical resistance of the plaque. Certain substrates may require treatment in an alkali solution to dissolve filler materials thereby increasing porosity to a required 65%.

Reid, M. A.; Post, R. E.; Soltis, D. G. (inventors)



Mobile floating carotid plaque post-trauma. Diagnosis and treatment.  


We report the cases of two patients with mobile floating carotid plaques (MFCP). Two men were referred to us for carotid investigation after trauma. The duplex ultrasonography scan (DUS) showed the presence of a mobile floating plaque into the internal carotid artery associated with a stenosis of 40% and 65%, respectively (ECST criteria). Both patients were asymptomatic. Early CEA was performed (<24 h after admission). Intraoperatively it was confirmed the presence of MFCP. The patients were discharged without neurological symptoms two days postoperatively. At the follow-up the DUS showed the patency of the CEA without restenosis or residual flap. PMID:19151001

Ferrero, Emanuele; Gaggiano, Andrea; Ferri, Michelangelo; Nessi, Franco



Dosimetric study of the 15 mm ROPES eye plaque  

SciTech Connect

The main aim of this paper is to make a study of dose-rate distributions obtained around the 15 mm, radiation oncology physics and engineering services, Australia (ROPES) eye plaque loaded with {sup 125}I model 6711 radioactive seeds. In this study, we have carried out a comparison of the dose-rate distributions obtained by the algorithm used by the Plaque Simulator (PS) (BEBIG GmbH, Berlin, Germany) treatment planning system with those obtained by means of the Monte Carlo method for the ROPES eye plaque. A simple method to obtain the dose-rate distributions in a treatment planning system via the superposition of the dose-rate distributions of a seed placed in the eye plaque has been developed. The method uses eye plaque located in a simplified geometry of the head anatomy and distributions obtained by means of the Monte Carlo code GEANT4. The favorable results obtained in the development of this method suggest that it could be implemented on a treatment planning system to improve dose-rate calculations. We have also found that the dose-rate falls sharply along the eye and that outside the eye the dose-rate is very low. Furthermore, the lack of backscatter photons from the air located outside the eye-head phantom produces a dose reduction negligible for distances from the eye-plaque r<1 cm but reaches up to 20% near the air-eye interface. Results showed that the treatment planning system lacks accuracy around the border of the eye (in the sclera and the surrounding area) due to the simplicity of the algorithm used. The BEBIG treatment planning system uses a global attenuation factor that takes into account the effect of the eye plaque seed carrier and the lack of backscatter photons caused by the metallic cover, which in the case of a ROPES eye plaque has a default value of T=1 (no correction). In the present study, a global attenuation factor T=0.96 and an air-interface correction factor which improve on treatment planning system calculations were obtained.

Granero, D.; Perez-Calatayud, J.; Ballester, F.; Casal, E.; Frutos, J.M. de [Department of Atomic, Molecular and Nuclear Physics and IFIC, University of Valencia-CSIC, Dr. Moliner 50, E46100 Burjassot (Spain); Medical Physics Section, University Hospital, Av. Ramon y Cajal 3, E47011 Valladolid (Spain)



Dynamics of the Microglial/Amyloid Interaction Indicate a Role in Plaque Maintenance  

PubMed Central

Microglial cells aggregate around amyloid plaques in Alzheimer's disease, but, despite their therapeutic potential, various aspects of their reactive kinetics and role in plaque pathogenesis remain hypothetical. Through use of in vivo imaging and quantitative morphological measures in transgenic mice, we demonstrate that local resident microglia rapidly react to plaque formation by extending processes and subsequently migrating toward plaques, in which individual transformed microglia somata remain spatially stable for weeks. The number of plaque-associated microglia increased at a rate of almost three per plaque per month, independent of plaque volume. Larger plaques were surrounded by larger microglia, and a subset of plaques changed in size over time, with an increase or decrease related to the volume of associated microglia. Far from adopting a more static role, plaque-associated microglia retained rapid process and membrane movement at the plaque/glia interface. Microglia internalized systemically injected amyloid-binding dye at a much higher rate in the vicinity of plaques. These results indicate a role for microglia in plaque maintenance and provide a model with multiple targets for therapeutic intervention. PMID:18417708

Bolmont, Tristan; Haiss, Florent; Eicke, Daniel; Radde, Rebecca; Mathis, Chester A.; Klunk, William E.; Kohsaka, Shinichi; Jucker, Mathias



Component external leakage and rupture frequency estimates  

SciTech Connect

In order to perform detailed internal flooding risk analyses of nuclear power plants, external leakage and rupture frequencies are needed for various types of components - piping, valves, pumps, flanges, and others. However, there appears to be no up-to-date, comprehensive source for such frequency estimates. This report attempts to fill that void. Based on a comprehensive search of Licensee Event Reports (LERs) contained in Nuclear Power Experience (NPE), and estimates of component populations and exposure times, component external leakage and rupture frequencies were generated. The remainder of this report covers the specifies of the NPE search for external leakage and rupture events, analysis of the data, a comparison with frequency estimates from other sources, and a discussion of the results.

Eide, S.A.; Khericha, S.T.; Calley, M.B.; Johnson, D.A.; Marteeny, M.L.



Acoustic levels of heavy truck tire ruptures.  


Transportation vehicles, whether they are passenger vehicles or heavy trucks and transport vehicles, rely upon rubber tires to negotiate the roadways and surfaces on which they are driven. These tires have the potential of sudden rupture resulting from various causes including but not limited to over-pressurization, sidewall failures, or punctures from roadway debris. These rupture events can and do occur while the vehicles are stationary (e.g., during servicing) or are being driven, and often occur without notice. While the phenomenon of sudden tire failure has been documented for several decades, the potential bodily injury which can occur when an individual is in close proximity to such a sudden rupture has only more recently been documented. Aside from anecdotal mention in case studies, there has been little quantitative information available on the acoustic levels during these failures. Our study provides measured acoustic levels as a function of distance for such catastrophic tire failures. PMID:23622472

Wood, Matthew; Woodruff, William



Ruptured venous aneurysm of cervicomedullary junction  

PubMed Central

Background: Ruptured venous aneurysm is often seen with arterio-venous malformation (AVM) or developmental venous anomaly (DVA). However, isolated venous aneurysm is unusual. Case Description: We present a case of ruptured venous aneurysm that presented with subarachnoid hemorrhage (SAH) and intraventricular hemorrhage (IVH). Digital substraction angiography (DSA) revealed a saccular contrast filling pouch in the left lateral aspect of cervicomedullary junction (CMJ). Endovascular intervention was not a viable option. During surgery, a saccular pliable structure approx. 1.5 × 1 cm was found in the subarachnoid space that was clipped and excised. There were no arterial feeders, no evidence of surrounding AVM, and no dilated perimedullary vein. Conclusion: This is perhaps the first reported case of ruptured venous aneurysm (without associated AVM) of CMJ, which was successfully managed surgically. The possible etiologies remain an unnoticed head trauma or a congenital vessel wall abnormality. Surgically clipping and excision remains the treatment of choice for such lesion. PMID:24575317

Aggarwal, Ashish; Salunke, Pravin; Futane, Sameer; Mathuriya, S. N.; Kumar, Ajay; Mukherjee, K. K.; Radotra, B. D.



[Apophyseal rupture of ischial bone tuberosity].  


The apophyses of the pelvic skeleton are the insertion zones of strong muscles and tendons and are soft points towards the end of growth. Apophyseal ruptures have quite often occurred as a consequence of overstressing in the context of certain athletic disciplines. Reported in this paper are two of the authors' own cases of apophyseal rupture of Tuber ossis ischii. Diagnosis is easy on the basis of case history, clinical manifestations, and X-ray. Treatment is conservative, with the patient hip-straightened confined to bed for three weeks. Surgery might be indicated in cases of continued seating problems or neurological failures. PMID:3577444

Lindner, H O; Winkeltau, G; Kalemba, J



Myocardial Rupture following Carbon Monoxide Poisoning  

PubMed Central

We present the first case of severe cardiotoxicity of carbon monoxide leading to myocardial rupture and fatal outcome. 83-year-old woman was hospitalized 4 hours after the fire in her house with no respiratory or cardiac symptoms. After two days, she has suffered sudden collapse leading to cardiac arrest. Postmortem examination revealed intramural haemorrhage with myocardial rupture at the apex of the left ventricle. Minimal stenosis was noted in the proximal coronary arteries with no evidence of distal occlusion or any other long-standing heart disease. This case supports recommendations for targeted cardiovascular investigations in cases of CO poisoning. PMID:25110594

Dragelyte, Gabija; Plenta, Juris; Chmieliauskas, Sigitas; Jasulaitis, Algimantas; Raudys, Romas; Jovaisa, Tomas; Badaras, Robertas



Microflora and chemical composition of dental plaque from subjects with hereditary fructose intolerance.  

PubMed Central

We compared the microbiological and chemical composition of dental plaque from subjects with hereditary fructose intolerance who restrict their dietary sugar intake with that of control subjects who do not. The two groups showed no significant differences in chemical composition of plaque: the mean protein, carbohydrate, calcium, magnesium, and phosphate contents were similar. Dental plaque from both groups contained similar numbers of total colony-forming units per microgram of plaque protein, and Streptococcus sanguis, an indigenous nonpathogen, was isolated with equal frequency from plaque samples of both groups. However, potentially odontopathic Streptococcus mutans and Lactobacillus were isolated three to four times more frequently from plaque samples of control subjects than from plaque samples of subjects with hereditary fructose intolerance. Clearly, diet (sucrose in particular) influences the colonization and multiplication of specific cariogenic organisms in dental plaque. PMID:7399699

Hoover, C I; Newbrun, E; Mettraux, G; Graf, H



Impact of local vessel curvature on the circumferential plaque distribution in coronary arteries  

E-print Network

the 3-D borders of the lumen/plaque and media/adventitia interfaces. Within each frame, plaque thickness with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple

Wahle, Andreas


Quantification of coronary hemodynamics and plaque morphology using x-ray angiography and  

E-print Network

Quantification of coronary hemodynamics and plaque morphology using x-ray angiography arteries by fusion of data from x-ray angiography and intravascular ultrasound (IVUS) and elaborates angiography, intravascular ultrasound 1. Introduction Understanding the mechanisms of plaque development

Wahle, Andreas


Mechanism of ceroid formation in atherosclerotic plaque: in situ studies combination of Raman and fluorescence spectroscopy  

E-print Network

Accumulation of the lipid-protein complex ceroid is a characteristic of atherosclerotic plaque. The mechanism of ceroid formation has been extensively studied, because the complex is postulated to contribute to plaque ...

Haka, Abigail S.


Plaque: What It Is and How to Get Rid of It  


... to the teeth. • Some types of plaque cause tooth decay. • Other types of plaque cause gum disease. Red, ... sweets, provide nutrients for the germs that cause tooth decay, as well as those that cause gum disease. ...


Risk of rupture in unruptured anterior communicating artery aneurysms: meta-analysis of natural history studies  

Microsoft Academic Search

BackgroundThe decision of whether to operate on patients bearing UIAs is complicated by the limitations in current knowledge of the natural history of such lesions. The ISUIA has estimated the annual risk of rupture below that justifying surgery for most incidentally found lesions less than 7 mm in diameter. However, there is some evidence that aneurysms located in the ACoA

Juan Marcos Suárez Mira; Fernando Antonio De Oliveira Costa; Bernardo Lessa Horta; Othello Moreira Fabião



Moderate Ruptures at a Megathrust Segment Boundary: The MW 7.2-7.3 Simeulue Earthquakes of 2002, 2008, and 2010  

NASA Astrophysics Data System (ADS)

Simeulue island, off the west coast of northern Sumatra, straddles the boundary of the great 2004 and 2005 Sunda megathrust ruptures. These ruptures nucleated north and southeast of Simeulue, respectively. Each propagated bilaterally toward the 100-km-long island. The net uplift was 1.5 m at both the northwest and southeast tips of the island but diminished markedly toward the island’s center. This implies the existence of a barrier to rupture under the island. Paleoseismic observations suggest that this barrier has persisted for at least the past 11 centuries, through perhaps three sequences of adjacent great ruptures. In addition to the 2004 and 2005 earthquakes, three moderate megathrust ruptures have also occurred near central Simeulue recently: a MW 7.2 on 2 Nov 2002, a MW 7.3 on 20 Feb 2008, and another MW 7.2 on 9 May 2010. Data from coral microatolls, continuous GPS (SuGAr), InSAR (ALOS PALSAR), and the global seismic network allow us to document surface deformation and model fault slip for each earthquake. We find that these three moderate earthquakes were not “repeat” events; instead, they were caused by rupture of adjacent or nearly adjacent patches of the megathrust, on the periphery of the 2004 rupture and between the 2004 and 2005 ruptures. The 2002 and 2008 ruptures, and perhaps the 2010 rupture as well, illuminate a narrow north-south trending patch of megathrust between the 2004 and 2005 ruptures, which may produce exclusively moderate and smaller earthquakes. Uplifts during the 2002 and 2008 events are far too small to completely fill the current uplift deficit across central Simeulue. Aside from a MW 7.0 earthquake on 20 Jun 1976 that produced no appreciable uplift on Simeulue, the historical record precludes other similar earthquakes for at least a century prior to 2002. We speculate that additional ruptures may fill the gap in the next few decades.

Meltzner, A. J.; Grijalva, K. A.; Sladen, A.; Sieh, K. E.; Bürgmann, R.; Banerjee, P.; Genrich, J. F.; Natawidjaja, D. H.; Suwargadi, B. W.; Galetzka, J. E.



The Predominant Cultivable Flora of Carious Plaque and Carious Dentine  

Microsoft Academic Search

The quantitative recovery of bacteria from single localized sites, namely the interproximal plaque over a carious lesion and the underlying carious dentine, was undertaken. The samples were collected with minimal oxygen exposure and after dispersion and serial dilution were plated on mitis salivarius agar and various formulations of MM10 agar (a dilute trypticase, yeast extract medium). Higher total counts, Strep,

W. J. Loesche; S. A. Syed



Interstellar Message Plaques: Application of White-Light Holography  

NASA Astrophysics Data System (ADS)

During Spring / Summer 2001, a prototype white-light holographic interstellar-probe message plaque was created under Contract H-29712D of NASA Marshall Spaceflight Center (MSFC), and commercial white-light holograms were tested for space-radiation tolerance at the MSFC Space Environment Facility (SEF) in Huntsville, AL, USA. Artist C Bangs' message plaque was created at the Center for Holographic Arts in Long Island City, NY. The 57.5 X 47.5 cm rainbow hologram was delivered to MSFC after framing by Simon Liu Inc., Brooklyn, NY, USA. The prototype message plaque, which is in the collection of the MSFC Space Transportation Directorate, has six multiplexed 2-D and 3-D images representing humans, the hypothetical interstellar spacecraft, and our position in the galaxy. Consultation with John Caulfield of Fisk University, an expert in holography, revealed that micron-thick holograms not much larger than a sheet of paper could contain hundreds of thousands of images, which opens the me ssage-plaque field considerably so that work of many artists could be included. Tests of commercial holograms at up to 100 MRad of simulated solar-wind radiation were performed at MSFC / SEF. Image-quality deterioriation was monitored using the image-color- histogram of the (trademarked) Adobe Photoshop software package. No significant deterioration occurred, which is in agreement with the literature. Holographic solar sails may be a propulsive application of this technology.

Matloff, G. L.



Intracellular amyloid and the neuronal origin of Alzheimer neuritic plaques.  


Genetic analysis of familial forms of Alzheimer's disease (AD) causally links the proteolytic processing of the amyloid precursor protein (APP) and AD. However, the specific type of amyloid and mechanisms of amyloid pathogenesis remain unclear. We conducted a detailed analysis of intracellular amyloid with an aggregation specific conformation dependent monoclonal antibody, M78, raised against fibrillar Aß42. M78 immunoreactivity colocalizes with Aß and the carboxyl terminus of APP (APP-CTF) immunoreactivities in perinuclear compartments at intermediate times in 10month 3XTg-AD mice, indicating that this represents misfolded and aggregated protein rather than normally folded APP. At 12months, M78 immunoreactivity also accumulates in the nucleus. Neuritic plaques at 12months display the same spatial organization of centrally colocalized M78, diffuse chromatin and neuronal nuclear NeuN staining surrounded by peripheral M78 and APP-CTF immunoreactivity as observed in neurons, indicating that neuritic plaques arise from degenerating neurons with intracellular amyloid immunoreactivity. The same staining pattern was observed in neuritic plaques in human AD brains, showing elevated intracellular M78 immunoreactivity at intermediate stages of amyloid pathology (Braak A and B) compared to no amyloid pathology and late stage amyloid pathology (Braak 0 and C, respectively). These results indicate that intraneuronal protein aggregation and amyloid accumulation is an early event in AD and that neuritic plaques are initiated by the degeneration and death of neurons by a mechanism that may be related to the formation of extracellular traps by neutrophils. PMID:25092575

Pensalfini, Anna; Albay, Ricardo; Rasool, Suhail; Wu, Jessica W; Hatami, Asa; Arai, Hiromi; Margol, Lawrence; Milton, Saskia; Poon, Wayne W; Corrada, Maria M; Kawas, Claudia H; Glabe, Charles G



Detail, bridge plaque at balustrade of south abutment, from south, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail, bridge plaque at balustrade of south abutment, from south, showing bridge construction in 1916 by city of Johnstown to design by Gustav A. Flink, designer and consulting engineer - Horner Street Bridge, Horner Street over Stonycreek River, Johnstown, Cambria County, PA



Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VARIABLE-ANGLE LAUNCHER DEDICATION PLAQUE SHOWING JAMES H. JENNISON (LEFT), AND W.H. SAYLOR (RIGHT), AT THE DEDICATION CEREMONY, May 7, 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA


Increased Expression of Wnt5a in Psoriatic Plaques  

Microsoft Academic Search

Psoriasis vulgaris is characterized by hyperproliferation and incomplete terminal differentiation of epidermal keratinocytes. Despite the established role of Wnt pathways in the regulation of stem cell proliferation and differentiation, they have not yet been associated with the pathophysiology of psoriasis. Here, we took biopsies from uninvolved and from lesional skin of 20 patients with plaque-type psoriasis. The biopsies were used

Joachim Reischl; Susanne Schwenke; Johanna M Beekman; Ulrich Mrowietz; Steffen Stürzebecher; Jürgen F Heubach



Amyloid Plaque Core Protein in Alzheimer Disease and Down Syndrome  

Microsoft Academic Search

We have purified and characterized the cerebral amyloid protein that forms the plaque core in Alzheimer disease and in aged individuals with Down syndrome. The protein consists of multimeric aggregates of a polypeptide of about 40 residues (4 kDa). The amino acid composition, molecular mass, and NH2-terminal sequence of this amyloid protein are almost identical to those described for the

Colin L. Masters; Gail Simms; Nicola A. Weinman; Gerd Multhaup; Brian L. McDonald; Konrad Beyreuther



Optical coherence tomography for imaging the vulnerable plaque  

NASA Astrophysics Data System (ADS)

While our understanding of vulnerable coronary plaque is still at an early stage, the concept that certain types of plaques predispose patients to developing an acute myocardial infarction continues to be at the forefront of cardiology research. Intracoronary optical coherence tomography (OCT) has been developed to both identify and study these lesions due to its distinct resolution advantage over other imaging modalities. We review clinical research conducted at the Massachusetts General Hospital over the past five years to develop, validate, and utilize this technology to improve our understanding of vulnerable plaque. Our results show that intracoronary OCT may be safely conducted in patients and that it provides abundant information regarding plaque microscopic morphology, which is essential to the identification and study of high-risk lesions. Even though many basic biological, clinical, and technological challenges must be addressed prior to widespread use of this technology, the unique capabilities of OCT ensure that it will have a prominent role in shaping the future of cardiology.

Tearney, Guillermo J.; Jang, Ik-Kyung; Bouma, Brett E.



Atherothrombosis and Plaque Heterology: Different Location or a Unique Disease?  

Microsoft Academic Search

Formation of unstable plaques frequently results in atherothrombosis, the major cause for ischaemic stroke, myocardial infarction and peripheral arterial disease. Patients who have symptomatic thrombosis in one vascular bed are at increased risk of disease in other beds. However, the development of the disease in carotid, coronary and peripheral arteries may have different pathophysiology suggesting that more complex treatment protocols

M. Slevin; Q. Wang; A. Luque; Oriol Juan-Babot; J. Gaffney; P. Kumar; S. Kumar; L. Badimon; J. Krupinski



Clinical Factors Associated With High-Risk Carotid Plaque Features as Assessed by Magnetic Resonance Imaging in Patients With Established Vascular Disease (from the AIM-HIGH Study).  


Association between clinical factors and high-risk plaque features, such as, thin or ruptured cap, intraplaque hemorrhage, presence of lipid-rich necrotic core (LRNC), and increased LRNC volume as assessed by magnetic resonance imaging (MRI), was examined in patients with established vascular disease in the Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides (AIM-HIGH) trial. A total of 214 subjects underwent carotid MRI and had acceptable image quality for assessment of plaque burden, tissue contents, and MRI-modified American Heart Association lesion type by a core laboratory. We found that 77% of subjects had carotid plaques, 52% had lipid-containing plaques, and 11% had advanced American Heart Association type-VI lesions with possible surface defect, intraplaque hemorrhage, or mural thrombus. Type-VI lesions were associated with older age (odds ratio [OR] = 2.6 per 5 years increase, p <0.001). After adjusting for age, these lesions were associated with history of cerebrovascular disease (OR = 4.1, p = 0.01), higher levels of lipoprotein(a) (OR = 2.0 per 1 SD increase, p = 0.02), and larger percent wall volume (PWV [OR = 4.6 per 1 SD increase, p <0.001]) but, were negatively associated with metabolic syndrome (OR = 0.2, p = 0.02). Presence of LRNC was associated with the male gender (OR = 3.2, p = 0.02) and PWV (OR = 3.8 per 1 SD, p <0.001); however, it was negatively associated with diabetes (OR = 0.4, p = 0.02) and high-density lipoprotein cholesterol levels (OR = 0.7 per 1 SD, p = 0.02). Increased percent LRNC was associated with PWV (regression coefficient = 0.36, p <0.001) and negatively associated with ApoA1 levels (regression coefficient = -0.20, p = 0.03). In conclusion, older age, male gender, history of cerebrovascular disease, larger plaque burden, higher lipoprotein(a), and lower high-density lipoprotein cholesterol or ApoA1 level have statistically significant associations with high-risk plaque features. Metabolic syndrome and diabetes showed negative associations in this population. PMID:25245415

Zhao, Xue-Qiao; Hatsukami, Thomas S; Hippe, Daniel S; Sun, Jie; Balu, Niranjan; Isquith, Daniel A; Crouse, John R; Anderson, Todd; Huston, John; Polissar, Nayak; O'Brien, Kevin; Yuan, Chun



Japanese Circulation Journal Vol.65, February 2001 he stability of atherosclerotic plaques depends greatly  

E-print Network

Japanese Circulation Journal Vol.65, February 2001 he stability of atherosclerotic plaques depends, are expressed in foam cell rich regions in atheromatous plaques.2 MMP-9, which degrades non-fibrillar collagen, is also known to be expressed in atherosclerotic plaques.3 Tumor necrosis factor receptor superfamily

Lee, Won-Ha


Controlling the angiogenic switch in developing atherosclerotic plaques: Possible targets for therapeutic intervention  

Microsoft Academic Search

Plaque angiogenesis may have an important role in the development of atherosclerosis. Vasa vasorum angiogenesis and medial infiltration provides nutrients to the developing and expanding intima and therefore, may prevent cellular death and contribute to plaque growth and stabilization in early lesions. However in more advanced plaques, inflammatory cell infiltration, and concomitant production of numerous pro-angiogenic cytokines may be responsible

Mark Slevin; Jerzy Krupinski; Lina Badimon




E-print Network

THE ROLE OF IRON PLAQUES IN IMMOBILIZING ARSENIC IN THE RICE-ROOT ENVIRONMENT by Cecily Eiko Moyer that iron (Fe) plaques, consisting mainly of amorphous iron oxides, grow on the surfaces of the rice roots. Iron plaques sorb As, immobilizing the toxin, preventing it from absorption into the plant body

Sparks, Donald L.



E-print Network


Sparks, Donald L.


Distribution of Inflammatory Cells in Atherosclerotic Plaques Relates to the Direction of Flow  

Microsoft Academic Search

Background—The distribution of macrophages and smooth muscle cells (SMCs) within atherosclerotic plaques is highly variable. This is clinically relevant because these cell types have opposite effects on the stability of atherosclerotic plaques. The present study was designed to investigate whether local variations in arterial flow over the plaque surface could relate to differences in the distribution of SMCs and macrophages

Maurits T. Dirksen; Allard C. van der Wal; Frank M. van den Berg; Chris M. van der Loos; Anton E. Becker


Occurrence of pleural plaques in workers with exposure to mineral wool  

Microsoft Academic Search

The objective of this study was to investigate whether occurrence of pleural plaques is associated with exposure to mineral wool. The occurrence of pleural plaques on routine chest radiographs of 933 persons employed in the mineral wool manufacturing industry and 865 referents was compared. Twelve men from the mineral wool industry had pleural plaques, as against three of the referents

Bengt Järvholm; Gunnar Hillerdal; Anna-Karin Järliden; Alf Hansson; Bengt-Gunnar Lilja; Göran Tornling; Peter Westerholm



The microglial phagocytic role with specific plaque types in the Alzheimer disease brain  

Microsoft Academic Search

Alzheimer disease (AD) involves glial inflammation associated with amyloid plaques. The role of the microglial cells in the AD brain is controversial, as it remains unclear if the microglia form the amyloid fibrils of plaques or react to them in a macrophage-phagocytic role. Also, it is not known why microglia are preferentially associated with some amyloid plaque types. This review

Michael R D’Andrea; Gregory M. Cole; March D. Ard



Atherosclerotic Plaque at the Carotid Bifurcation: CT Angiographic Appearance with Histopathologic Correlation  

Microsoft Academic Search

BACKGROUND AND PURPOSE:The likelihood that carotid plaque will give rise to cerebral ischemia probably relates to the degree of arterial stenosis and to plaque morphology. The aim of this study was to assess whether features seen at CT angiography might be used to predict carotid plaque stability by comparing CT angiograms with histopathologic examinations of the carotid artery bifurcation. METHODS:

T. Barry Oliver; G. Alistair Lammie; Andrew R. Wright; Joanna Wardlaw; Sandi G. Patel; Russell Peek; C. Vaughan Ruckley; Donald A. Collie


Phylogenetic and structural studies of a novel equine papillomavirus identified from aural plaques.  


Papillomaviruses (PVs) infect a wide range of animal species and show great genetic diversity. To date, excluding equine sarcoids, only three species of PVs were identified associated with lesions in horses: Equus caballus papillomavirus 1 (EcPV1-cutaneous), EcPV2 (genital) and EcPV3 (aural plaques). In this study, we identified a novel equine PV from aural plaques, which we designated EcPV4. Cutaneous samples from horses with lesions that were microscopically diagnosed as aural plaques were subjected to DNA extraction, amplification and sequencing. Rolling circle amplification and inverse PCR with specific primers confirmed the presence of an approximately 8 kb circular genome. The full-length EcPV4 L1 major capsid protein sequence has 1488 nucleotides (495 amino acids). EcPV4 had a sequence identity of only 53.3%, 60.2% and 51.7% when compared with the published sequences for EcPV1, EcPV2 and EcPV3, respectively. A Bayesian phylogenetic analysis indicated that EcPV4 clusters with EcPV2, but not with EcPV1 and EcPV3. Using the current PV classification system that is based on the nucleotide sequence of L1, we could not define the genus of the newly identified virus. Therefore, a structural analysis of the L1 protein was carried out to aid in this classification because EcPV4 cause lesion similar to the lesion caused by EcPV3. A comparison of the superficial loops demonstrated a distinct amino acid conservation pattern between EcPV4/EcPV2 and EcPV4/EcPV3. These results demonstrate the presence of a new equine PV species and that structural studies could be useful in the classification of PVs. PMID:22995874

Taniwaki, Sueli A; Magro, Angelo J; Gorino, Ana Claudia; Oliveira-Filho, José P; Fontes, Marcos R M; Borges, Alexandre S; Araujo, João P



Postintubation Tracheal Ruptures - A case report -  

PubMed Central

Tracheobronchial ruptures (TBR) rarely complicate surgical procedures under general anesthesia. Seemingly uneventful intubations can result in injury to the trachea, which often manifests as hemoptysis and subcutaneous emphysema. We present 2 patients with postintubation TBR who were treated surgically and discuss considerations in the management of this potentially lethal injury. PMID:22263165

Kim, Kyung Hwa; Choi, Jong-Bum; Kuh, Ja-Hong; Jo, Jung-Ku; Park, Hyun Kyu



Star polymers rupture induced by constant forces.  


In this work, we study the breakage process of an unknotted three-arm star-shaped polymer when it is pulled from its free ends by a constant force. The star polymer configuration is described through an array of monomers coupled by anharmonic bonds, while the rupture process is tracked in three-dimensional space by means of Langevin Molecular Dynamics simulations. The interaction between monomers is described by a Morse potential, while a Weeks-Chandler-Anderson energetic contribution accounts for the excluded volume interaction. We explore the effect of the molecular architecture on the distributions of rupture times over a broad interval of pulling forces and star configurations. It was found that the rupture time distribution of the individual star arms is strongly affected by the star configuration imposed by the pulling forces and the length of the arms. We also observed that for large pulling forces the rupture time distributions resemble the dominant features observed for linear polymer chains. The model introduced here provides the basic ingredients to describe the effects of tensile forces on stress-induced degradation of branched macromolecules and polymer networks. PMID:25362341

García, N A; Febbo, M; Vega, D A; Milchev, A



Penile Fracture with Associated Urethral Rupture  

PubMed Central

Penile fracture of the erect penis is an uncommon but emergent urological trauma. Potential outcomes include erectile dysfunction, penile curvature, and urethral injury. Treatment is emergent surgical repair. We present the case of a 42-year-old man with a penile fracture complicated by a urethral rupture and subsequent repair. A discussion of the key aspects of this condition is presented. PMID:21076536

Boncher, Nicholas A.; Vricella, Gino J.; Jankowski, Jason T.; Ponsky, Lee E.; Cherullo, Edward E.



Star polymers rupture induced by constant forces  

NASA Astrophysics Data System (ADS)

In this work, we study the breakage process of an unknotted three-arm star-shaped polymer when it is pulled from its free ends by a constant force. The star polymer configuration is described through an array of monomers coupled by anharmonic bonds, while the rupture process is tracked in three-dimensional space by means of Langevin Molecular Dynamics simulations. The interaction between monomers is described by a Morse potential, while a Weeks-Chandler-Anderson energetic contribution accounts for the excluded volume interaction. We explore the effect of the molecular architecture on the distributions of rupture times over a broad interval of pulling forces and star configurations. It was found that the rupture time distribution of the individual star arms is strongly affected by the star configuration imposed by the pulling forces and the length of the arms. We also observed that for large pulling forces the rupture time distributions resemble the dominant features observed for linear polymer chains. The model introduced here provides the basic ingredients to describe the effects of tensile forces on stress-induced degradation of branched macromolecules and polymer networks.

García, N. A.; Febbo, M.; Vega, D. A.; Milchev, A.



Bond-rupture immunosensors--a review.  


It has long been the goal of researchers to develop fast and reliable point-of-care alternatives to existing lab-based tests. A viable point-of-care biosensor is fast, reliable, simple, cost-effective, and detects low concentrations of the target analyte. The target of biosensors is biological such as bacteria or virus and as such, the antibody-antigen bond derived from the real immune response is used. Biosensor applications include lab-based tests for the purposes of diagnostics, drug discovery, and research. Additional applications include environmental, food, and agricultural monitoring. The main merits of the bond-rupture method are quick, simple, and capable of discriminating between specific and non-specific interactions. The separation of specific and non-specific bonds is important for working in real-life complex serums such as blood. The bond-rupture technique can provide both qualitative results, the detection of a target, and quantitative results, the concentration of target. Bond-rupture achieves this by a label-free method requiring no pre-processing of the analyte. A piezoelectric transducer such as the quartz crystal microbalance (QCM) shakes the bound particles free from the surface. Other transducers such as Surface Acoustic Wave (SAW) are also considered. The rupture of the bonds is detected as electronic noise. This review article links diverse research areas to build a picture of a field still in development. PMID:18343101

Hirst, Evan R; Yuan, Yong J; Xu, W L; Bronlund, J E



Unusual rupture of a flexor profundus tendon.  


An unusual rupture of a flexor profundus tendon, previously unreported in the literature, is presented. There was avulsion and proximal displacement of a large bone fragment from the palmar base of the distal phalanx and further retraction of the tendon unattached to the bone fragment. PMID:3958452

Langa, V; Posner, M A



Fault branching and rupture directivity Sonia Fliss  

E-print Network

, some understanding of the mechanics underlying dynamic processes of fault branching and jumping has earthquake from the rupture pattern it left? The answer to that question would be very useful for risk assessment of future earthquakes, even if it is cur- rently unknown if large earthquakes do systematically

Dmowska, Renata


Laparoscopic splenectomy for atraumatic splenic rupture.  


A traumatic splenic rupture (ASR) is a rare clinical entity. Several underlying benign and malignant conditions have been described as a leading cause. We report on a case of ASR in a 41-year-old man treated with laparoscopic splenectomy. Considering ASR as a life-threatening condition, a prompt diagnosis can be life saving. PMID:21675627

Grossi, Ugo; Crucitti, Antonio; D'Amato, Gerardo; Mazzari, Andrea; Tomaiuolo, Pasquina M C; Cavicchioni, Camillo; Bellantone, Rocco



What Is an Earthquake?: Rupture Models  

NSDL National Science Digital Library

In this activity, the learner will watch three animations based on actual data from fault ruptures from the two largest Southern California earthquakes in the 1990s: Landers (1992) and Northridge (1994). In Section 3, the learner will discover more about how such data is collected and analyzed.


Surface Rupture in Northwest Saudi Arabia  

USGS Multimedia Gallery

Wendy McCausland of the USGS Volcano Disaster Assistance Program and Hani Zahran of the Saudi Geological Survey view the southern end of the surface fault rupture caused by a M5.4 earthquake in the Saudi Arabian desert on May 19, 2009. The ground displacements in the soft sediments of the foreground...



Fiber Breakage Model for Carbon Composite Stress Rupture Phenomenon: Theoretical Development and Applications  

NASA Technical Reports Server (NTRS)

Stress rupture failure of Carbon Composite Overwrapped Pressure Vessels (COPVs) is of serious concern to Science Mission and Constellation programs since there are a number of COPVs on board space vehicles with stored gases under high pressure for long durations of time. It has become customary to establish the reliability of these vessels using the so called classic models. The classical models are based on Weibull statistics fitted to observed stress rupture data. These stochastic models cannot account for any additional damage due to the complex pressure-time histories characteristic of COPVs being supplied for NASA missions. In particular, it is suspected that the effects of proof test could significantly reduce the stress rupture lifetime of COPVs. The focus of this paper is to present an analytical appraisal of a model that incorporates damage due to proof test. The model examined in the current paper is based on physical mechanisms such as micromechanics based load sharing concepts coupled with creep rupture and Weibull statistics. For example, the classic model cannot accommodate for damage due to proof testing which every flight vessel undergoes. The paper compares current model to the classic model with a number of examples. In addition, several applications of the model to current ISS and Constellation program issues are also examined.

Murthy, Pappu L. N.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie



Echo-Lucency of Computerized Ultrasound Images of Carotid Atherosclerotic Plaques Are Associated With Increased Levels of Triglyceride-Rich Lipoproteins as Well as Increased Plaque Lipid Content  

Microsoft Academic Search

Background—Echo-lucency of carotid atherosclerotic plaques on computerized ultrasound B-mode images has been associated with a high incidence of brain infarcts as evaluated on CT scans. We tested the hypotheses that triglyceride-rich lipoproteins in the fasting and postprandial state predict carotid plaque echo-lucency and that echo-lucency predicts a high plaque lipid content. Methods and Results—The study included 137 patients with neurological

Marie-Louise M. Grønholdt; Børge G. Nordestgaard; Britt M. Wiebe; Jens E. Wilhjelm; Henrik Sillesen


In vitro antiplaque activity of octenidine dihydrochloride (WIN 41464-2) against preformed plaques of selected oral plaque-forming microorganisms.  

PubMed Central

The antibacterial activity of octenidine dihydrochloride (WIN 41464-2) against intact preformed in vitro plaques of four indigenous oral plaque-forming microorganisms, Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, and Actinomyces naeslundii, was studied. Both absolute (plaque bactericidal index) and relative (chlorhexidine coefficient) indices of antiplaque efficacy were established. Octenidine dihydrochloride compared favorably with chlorhexidine digluconate with respect to overall antiplaque potency in this in vitro plaque bactericidal model. These data indicate that prudent selection of treatment concentration and duration and frequency of exposure should provide an effective means to aid in controlling dental caries and Actinomyces-associated disease in vivo. PMID:6847170

Slee, A M; O'Connor, J R



Lightweight porous plastic plaque. [nickel cadmium batteries  

NASA Technical Reports Server (NTRS)

The porosity and platability of various materials were investigated to determine a suitable substrate for nickel-plated electrodes. Immersion, ultrasonics, and flow-through plating techniques were tried using nonproprietary formulations, and proprietary phosphide and boride baths. Modifications to the selected material include variations in formulation and treatment, carbon loading to increase conductivity, and the incorporation of a grid. Problems to be solved relate to determining conductivities and porosities as a function of amount of nickel plated on the plastics; loading; charge and discharge curves of electrodes at different current densities; cell performance; and long-term degradation of electrodes.

Reid, M.



Rupture of the uterus in a primigravida: a case report.  


Uterine rupture during a first pregnancy is rare. We present the case of spontaneous intrapartum uterine rupture in a 40 year old primigravida with no prior uterine surgery, and a structurally normal uterus. The patient had obstructed labor. Operative findings were a male fresh stillbirth weighing 3800 g, massive hemoperitoneum, and an anterior transverse rupture at the lower uterine segment. Repair of the rupture was done without bilateral tubal ligation. Although a rare event, the primigravid uterus is not immune to rupture as exemplified by this report. PMID:20499765

Chigbu, B; Onwere, S; Kamanu, C; Aluka, C; Adibe, E; Onichakwe, C



Coronary Plaque Type and Burden By Computed Tomography Angiography Without Association to C-Reactive Protein  

PubMed Central

Background: Contrast-enhanced computed tomography angiography (CTA) of the coronaries allows identification of plaques. Limited data exists on the relationship between C-reactive protein (CRP) and the plaque type or plaque burden detected by CTA. Aims: We studied relationship between CRP and coronary atherosclerosis. Materials and Methods: 92 patients without history of coronary disease underwent coronary CTA for chest pain. Coronary arteries were evaluated with each detected plaque labeled as calcified, noncalcified or mixed. Logarithmic transformation was done on CRP values for statistical analysis. Results: 1380 coronary segments were evaluated. The average age was 57 years (SE 1.0) and basal metabolic index (BMI) 28.9 kg/m2 (SE 0.5). Median CRP level was 2.75 mg/L (range 0.17-16.98). No association was found between CRP quartiles and plaque type. In stepwise multivariate analysis, only diabetes was associated with noncalcified plaque (P < 0.001). When calcified and mixed plaques were added to the model, age (P < 0.001), diabetes (P < 0.02), and statin use (P < 0.05) were associated with an increased number of plaques per subject. No association was found between log-CRP for any type of plaque. Conclusion: There was no association between CRP and plaque type by CTA. Lack of association is likely due to limited spatial resolution and underestimation of noncalcified plaque burden by CTA. PMID:25006560

Navaravong, Leenhapong; Steenson, Carol; Sigurdsson, Gardar



Resistance of a vaccinia virus A34R deletion mutant to spontaneous rupture of the outer membrane of progeny virions on the surface of infected cells  

SciTech Connect

The extracellular form of vaccinia virus is referred to as an enveloped virion (EV) because it contains an additional lipoprotein membrane surrounding the infectious mature virion (MV) that must be discarded prior to cell fusion and entry. Most EVs adhere to the surface of the parent cell and mediate spread of the infection to adjacent cells. Here we show that some attached EVs have ruptured envelopes. Rupture was detected by fluorescence microscopy of unfixed and unpermeabilized cells using antibodies to the F13 and L1 proteins, which line the inner side of the EV membrane and the outer side of the MV membrane, respectively. The presence of ruptured EV membranes was confirmed by immunogold transmission electron microscopy. EVs with broken membranes were present on several cell lines examined including one deficient in glycosaminoglycans, which are thought to play a role in breakage of the EV membrane prior to fusion of the MV. No correlation was found between EVs with ruptured membranes and actin tail formation. Studies with several mutant viruses indicated that EV membranes lacking the A34 protein were unbroken. This result was consistent with other properties of A34R deletion mutants including resistance of the EV membrane to polyanions, small plaque formation and low infectivity that can be increased by disruption of the EV membrane by freezing and thawing.

Husain, Matloob; Weisberg, Andrea S. [Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Moss, Bernard [Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 (United States)], E-mail:



Texture based segmentation method to detect atherosclerotic plaque from optical tomography images  

NASA Astrophysics Data System (ADS)

Optical coherence tomography (OCT) imaging has been widely employed in assessing cardiovascular disease. Atherosclerosis is one of the major cause cardio vascular diseases. However visual detection of atherosclerotic plaque from OCT images is often limited and further complicated by high frame rates. We developed a texture based segmentation method to automatically detect plaque and non plaque regions from OCT images. To verify our results we compared them to photographs of the vascular tissue with atherosclerotic plaque that we used to generate the OCT images. Our results show a close match with photographs of vascular tissue with atherosclerotic plaque. Our texture based segmentation method for plaque detection could be potentially used in clinical cardiovascular OCT imaging for plaque detection.

Prakash, Ammu; Hewko, Mark; Sowa, Michael; Sherif, Sherif



Manganese and copper in the root plaque of Phragmites australis (cav. ) trin. ex steudel  

SciTech Connect

Manganese and copper were found in the iron oxide plaque on roots of Phragmites australis collected at six sampling sites in southern Quebec and Ontario, Canada. Manganese concentration in the plaque, like that of Fe, is correlated with Mn-bound-to-carbonates fraction of the soil/sediment. The Fe:Mn ratio of the plaque resemble the same ratio of Fe:Mn-bound-to-carbonates in the substrate. The ratio changes with environmental conditions, increasing with percentage of water and decreasing with pH. Plants located near flowing water accumulate more Mn (and Fe) in the plaque than plants in other habitats through the summer. Copper concentration in the plaque than plants in other habitats through the summer. Copper concentration in the plaque is pH-dependent and is positively correlated with the amount of Fe and Mn of the plaque, but appears to be related more closely to Mn.

St-Cyr, L.; Crowder, A.A. (Queen's Univ., Kingston, Ontario (Canada))



Modified murine intracranial aneurysm model: aneurysm formation and rupture by elastase and hypertension  

PubMed Central

Introduction Cerebral aneurysms occur in up to 5% of the population. There are several murine models of aneurysms; however, all have limitations and none reproducibly model aneurysm rupture. To fulfill this need, we modified two current rodent aneurysm models to create a murine model which reproducibly produces intracranial aneurysms and rupture. Methods The left common carotid arteries and the right renal arteries were ligated in C57BL/6 female mice with a hypertensive diet. One week later, small burr holes were created with a stereotactic frame using the following stereotactic measurements: 1.2?mm rostral and 0.7?mm lateral to the right of the bregma. A 26?G needle was gradually advanced via the burr hole until contact with the skull base, upon which the needle was pulled back 0.3?mm. Five, 10 and 20??L of 10?U/mL elastase solution and 10??L of 1?U/mL elastase solution were stereotactically injected into the basal cisterns. Angiotensin II was then continually infused at a dose of 1000?ng/kg/min via an osmotic pump placed subcutaneously. In the control mice, 20??L bromophenol blue solution was injected. Three weeks later, or earlier if mice expired prior to 3?weeks, the circle of Willis was inspected by microscopy for aneurysm formation and/or signs of rupture. Histological analyses were then performed to evaluate elastic lamina destruction, inflammatory cell and macrophage infiltration, absence of intimal endothelial cells and thickening of the smooth muscle layer within the aneurysm wall. To compare with human aneurysms, human aneurysm specimens (n=35; 34 unruptured and 1 ruptured) and normal control superficial temporal arteries (STAs) (n=9) were examined. Results All mice given 5, 10 and 20??L of 10?U/mL elastase solution developed intracranial aneurysms within the circle of Willis; 40%, 60% and 50% of mice had ruptured aneurysms, respectively. In mice given 10??L of 1.0?U/mL elastase solution, 90% developed intracranial aneurysms and 20% had ruptured aneurysms. Aneurysms were confirmed by examining the destruction of the elastic lamina. Aneurysms consistently demonstrated CD45 positive inflammatory cell and F4/80 positive macrophage infiltration within the aneurysm wall which was not present in the circle of Willis of normal sham-operated mice. These results were similar to those in human aneurysms and STA control arteries. Conclusions We modified two current rodent aneurysm models to create a murine model that produces consistent aneurysms and rupture and can be used for studying cerebral aneurysm formation, rupture and treatment. PMID:23943816

Hosaka, Koji; Downes, Daniel P; Nowicki, Kamil W; Hoh, Brian L



Fluorescence lifetime imaging for the characterization of the biochemical composition of atherosclerotic plaques  

NASA Astrophysics Data System (ADS)

This study investigates the ability of a flexible fiberoptic-based fluorescence lifetime imaging microscopy (FLIM) technique to resolve biochemical features in plaque fibrotic cap associated with plaque instability and based solely on fluorescence decay characteristics. Autofluorescence of atherosclerotic human aorta (11 autopsy samples) was measured at 48 locations through two filters, F377: 377/50 and F460: 460/60 nm (center wavelength/bandwidth). The fluorescence decay dynamic was described by average lifetime (?) and four Laguerre coefficients (LECs) retrieved through a Laguerre deconvolution technique. FLIM-derived parameters discriminated between four groups [elastin-rich (ER), elastin and macrophage-rich (E+M), collagen-rich (CR), and lipid-rich (LR)]. For example, ?F377 discriminated ER from CR (R = 0.84); ?F460 discriminated E+M from CR and ER (R = 0.60 and 0.54, respectively); LEC-1F377 discriminated CR from LR and E+M (R = 0.69 and 0.77, respectively); P < 0.05 for all correlations. Linear discriminant analysis was used to classify this data set with specificity >87% (all cases) and sensitivity as high as 86%. Current results demonstrate for the first time that clinically relevant features (e.g., ratios of lipid versus collagen versus elastin) can be evaluated with a flexible-fiber based FLIM technique without the need for fluorescence intensity information or contrast agents.

Phipps, Jennifer; Sun, Yinghua; Saroufeem, Ramez; Hatami, Nisa; Fishbein, Michael C.; Marcu, Laura



Detection of supershear rupture in 2013 Craig, Alaska, earthquake  

NASA Astrophysics Data System (ADS)

Seismic ruptures are akin to opening a zipper—a gap in the crust starts in one location and travels along the fault in a particular direction. When a strained fault ruptures in an earthquake, seismic waves also spread out from the epicenter. In some cases, the waves' passage can trigger the initiation of a new rupture ahead of the initial expanding rupture in locked portions of the fault. If the triggered rupture grows successfully, the overall rupture front can then outpace the passage of the shear waves, secondary seismic waves that travel slowly after the earthquake begins and are responsible for the bulk of violent shaking. These earthquakes display what is known as supershear rupture; only seven such earthquakes have previously been recorded.

Schultz, Colin



Longitudinal study of relations between human salivary antimicrobial proteins and measures of dental plaque accumulation and composition.  


Many studies have attempted to relate levels of antimicrobial proteins in saliva to oral health; results have been inconsistent, and one reason might be inconsistency of measures of plaque and saliva within subjects. This study investigated associations between plaque and salivary variables in longitudinal data. Whole saliva, and 8-h plaque pooled from buccal first permanent molars, was obtained from 32 dental students on Tuesdays from 3:00-6:00 p.m. over 4 weeks. Salivary flow rate was determined, and samples were assayed for lysozyme, lactoferrin, total peroxidase, myeloperoxidase, OSCN-, sIgA and total protein. Colonies on mitis-salivarius agar were assigned to Streptococcus sanguis, Strep. mutans or Strep. salivarius on the basis of morphology, supplemented by the API Rapid Strep identification system. Consistency of values within subjects across weeks was evaluated by repeat-measures analysis of variance and intraclass correlation; data were transformed to reduce skewness. Pearson's r was used to determine associations between plaque and salivary variables. Significant intraclass correlations (alpha = 0.05) were found for all salivary variables except myeloperoxidase, and for total flora, total streptococci, Strep. sanguis and Strep. sanguis as a proportion of total streptococci. Significant Pearson correlations with Strep. sanguis as a proportion of total streptococci were found for total protein (r = -0.24), sIgA (r = -0.22), lactoferrin (r = -0.19) and OSCN- (r = 0.20) when data from all weeks were pooled (n = 128). Strep. sanguis proportions tended to be low in subjects with high values for salivary proteins; the range of proportions was wider in subjects with low salivary values. These findings suggest some consistency of weekly values for many plaque and salivary variables. They also support previous cross-sectional data which suggested that salivary antimicrobial proteins may have some effect on plaque composition. This study was made before recent revisions in streptococcal taxonomy, and further research is needed to clarify interactions of salivary proteins with currently defined species. PMID:8392324

Rudney, J D; Krig, M A; Neuvar, E K



Real-time Finite Fault Rupture Detector (FinDer) for large earthquakes  

NASA Astrophysics Data System (ADS)

To provide rapid estimates of fault rupture extent during large earthquakes, we have developed the Finite Fault Rupture Detector algorithm, 'FinDer'. FinDer uses image recognition techniques to detect automatically surface-projected fault ruptures in real-time (assuming a line source) by estimating their current centroid position, length L, and strike ?. The approach is based on a rapid high-frequency near/far-source classification of ground motion amplitudes in a dense seismic network (station spacing <50 km), and comparison with a set of pre-calculated templates using 'Matching by Correlation'. To increase computational efficiency, we perform the correlation in the wavenumber domain. FinDer keeps track of the current dimensions of a rupture in progress. Errors in L are typically on the same order as station spacing in the network. The continuously updated estimates of source geometries as provided by FinDer make predicted shaking intensities more accurate and thus more useful for earthquake early warning, ShakeMaps, and related products. The applicability of the algorithm is demonstrated for several recorded and simulated earthquakes with different focal mechanisms, including the 2009 Mw 6.3 L'Aquila (Italy), the 1999 Mw 7.6 ChiChi (Taiwan) and the Mw 7.8 ShakeOut scenario earthquake on the southern San Andreas Fault (California).

Böse, Maren; Heaton, Thomas H.; Hauksson, Egill



The use of heparin in patients with ruptured abdominal aortic aneurysms.  


The use of systemic heparin in patients with ruptured abdominal aortic aneurysms (rAAAs) remains a contentious issue with no clear guidelines. This review reports the current understanding, at a molecular and clinical level, of the possible benefits and risks of heparin in emergency aneurysm repair (both open and endovascular). MEDLINE, EMBASE, AMED, SCOPUS, CINAHL and Cochrane Library were searched for all articles containing the keywords 'rupture', 'abdominal', 'aneurysm' and 'heparin'. Current experience, indications and outcomes were analyzed. Articles were searched for both endovascular and open repair of AAAs. A total of eight studies were included for analysis in the systematic review. Of these, only one paper focused specifically on heparin use in open repair of ruptures and suggested a benefit. Of the remaining seven, two were self-reporting retrospective studies assessing individual surgeons' practice, one was a case report and the remaining four included mention of heparin use but with no outcome data. The evidence available suggests that a pro-coagulable state exists in rAAAs. This may be responsible for the morbidity and mortality postprocedure, which arises predominantly from multiple organ failure and cardiac compromise rather than outright hemorrhage. This diathesis may respond well to heparin administration, suggesting that heparin administration in ruptured aneurysms is appropriate. PMID:22454548

Graham, A P; Fitzgerald O'Connor, E; Hinchliffe, R J; Loftus, I M; Thompson, M M; Black, S A



A synthetic GMPE based on deterministic simulated ground motion data obtained from dynamic rupture models  

NASA Astrophysics Data System (ADS)

Empirical ground motion prediction in the very near-field and for large magnitudes is often based on extrapolation of ground motion prediction equations (GMPEs) outside the range where they are well constrained by recorded data. With empirical GMPEs it is also difficult to capture source-dominated ground motion patterns, such as the effects of velocity pulses induced by subshear and supershear rupture directivity, buried and surface-rupturing, hanging-wall and foot-wall, weak shallow layers, complex geometry faults and stress drop. A way to cope at least in part with these shortcomings is to augment the calibration datasets with synthetic ground motions. To this aim, physics-based dynamic rupture models - where the physical bases involved in the fault rupture are explicitly considered - appear to be a suitable approach to produce synthetic ground motions. In this contribution, we first perform an assessment of a database of synthetic ground motions generated by a suite of dynamic rupture simulations to verify compatibility of the peak ground amplitudes with current GMPEs. The synthetic data-set is composed by 360 earthquake scenarios with moment magnitudes in the range of 5.5-7, for three mechanisms of faulting (reverse, normal and strike-slip) and for both buried faults and surface rupturing faults. Second, we parameterise the synthetic dataset through a GMPE. For this purpose, we identify the basic functional forms by analyzing the variation of the synthetic peak ground motions and spectral ordinates as a function of different explanatory variables related to the earthquake source characteristics, in order to account for some of the source effects listed above. We argue that this study provides basic guidelines for the developments of future GMPEs including data from physics-based numerical simulations.

Dalguer, L. A.; Baumann, C.; Cauzzi, C.



Modeling Plaque Fissuring and Dissection during Balloon Angioplasty Intervention  

Microsoft Academic Search

Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and\\/or dissection\\u000a occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization\\u000a of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment\\u000a site. We propose physical and finite element models, which are generally

T. Christian Gasser; Gerhard A. Holzapfel



Biofilms, a new approach to the microbiology of dental plaque  

Microsoft Academic Search

Dental plaque has the properties of a biofilm, similar to other biofilms found in the body and the environment. Modern molecular\\u000a biological techniques have identified about 1000 different bacterial species in the dental biofilm, twice as many as can be\\u000a cultured. Oral biofilms are very heterogeneous in structure. Dense mushroom-like structures originate from the enamel surface,\\u000a interspersed with bacteria-free channels

Jacob M. ten Cate



Sequencing viral genomes from a single isolated plaque  

PubMed Central

Background Whole genome sequencing of viruses and bacteriophages is often hindered because of the need for large quantities of genomic material. A method is described that combines single plaque sequencing with an optimization of Sequence Independent Single Primer Amplification (SISPA). This method can be used for de novo whole genome next-generation sequencing of any cultivable virus without the need for large-scale production of viral stocks or viral purification using centrifugal techniques. Methods A single viral plaque of a variant of the 2009 pandemic H1N1 human Influenza A virus was isolated and amplified using the optimized SISPA protocol. The sensitivity of the SISPA protocol presented here was tested with bacteriophage F_HA0480sp/Pa1651 DNA. The amplified products were sequenced with 454 and Illumina HiSeq platforms. Mapping and de novo assemblies were performed to analyze the quality of data produced from this optimized method. Results Analysis of the sequence data demonstrated that from a single viral plaque of Influenza A, a mapping assembly with 3590-fold average coverage representing 100% of the genome could be produced. The de novo assembled data produced contigs with 30-fold average sequence coverage, representing 96.5% of the genome. Using only 10 pg of starting DNA from bacteriophage F_HA0480sp/Pa1651 in the SISPA protocol resulted in sequencing data that gave a mapping assembly with 3488-fold average sequence coverage, representing 99.9% of the reference and a de novo assembly with 45-fold average sequence coverage, representing 98.1% of the genome. Conclusions The optimized SISPA protocol presented here produces amplified product that when sequenced will give high quality data that can be used for de novo assembly. The protocol requires only a single viral plaque or as little as 10 pg of DNA template, which will facilitate rapid identification of viruses during an outbreak and viruses that are difficult to propagate. PMID:23742765



Complete Processing of Type III Collagen in Atherosclerotic Plaques  

Microsoft Academic Search

The extent of processing of type III collagen is assessed, and the proportions of type I and III collagens are estimated in atherosclerotic plaques obtained from the carotid artery, common femoral artery, and aorta. The fraction of type III collagen that had retained its amino-terminal propeptide (pN-collagen) was 42% in the soluble extract but only 0.0081% in the insoluble residue.

Michaela K. Bode; Martti Mosorin; Jari Satta; Leila Risteli; Tatu Juvonen; Juha Risteli



Creep rupture behavior of Stirling engine materials  

NASA Technical Reports Server (NTRS)

The automotive Stirling engine, being investigated jointly by the Department of Energy and NASA Lewis as an alternate to the internal combustion engine, uses high-pressure hydrogen as the working fluid. The long-term effects of hydrogen on the high temperature strength properties of materials is relatively unknown. This is especially true for the newly developed low-cost iron base alloy NASAUT 4G-A1. This iron-base alloy when tested in air has creep-rupture strengths in the directionally solidified condition comparable to the cobalt base alloy HS-31. The equiaxed (investment cast) NASAUT 4G-A1 has superior creep-rupture to the equiaxed iron-base alloy XF-818 both in air and 15 MPa hydrogen.

Titran, R. H.; Scheuerman, C. M.; Stephens, J. R.



Treatment of Ruptured ICA during Transsphenoidal Surgery  

PubMed Central

Summary Rupture of the internal carotid artery (ICA) during transsphenoidal surgery is a rare but potentially lethal complication. Direct surgical repair of the ICA may be difficult and time-consuming in an acute setting. Urgent endovascular treatments with vascular plug or stent-graft have been the feasible options to date. We desrcibe two cases of iatrogenic rupture of ICA during transsphenoidal surgery. In the first case we occluded the ICA with a vascular plug at the site of tear where cross circulation was adequate. In the second case we had to preserve the ICA with stent-graft since there was no adequate cross circulation. These two strategies are discussed below. PMID:20377977

Ghatge, S.B.; Modi, D.B.



Retinal detachment associated with traumatic chorioretinal rupture.  


Traumatic chorioretinal rupture, also known as sclopetaria, is a full-thickness break of the choroid and retina caused by a high-velocity projectile striking or passing adjacent to, but not penetrating, the globe. Previous reports have emphasized that retinal detachment seldom occurs, and observation alone has been the recommended management strategy. However, the authors present herein a series of consecutive patients with retinal detachment associated with sclopetaria and provide a literature review of the topic. They recommend that patients with traumatic chorioretinal rupture be monitored closely for the development of retinal detachment during the first few weeks after the injury. [Ophthalmic Surg Lasers Imaging Retina. 2014;45:451-455.]. PMID:25153657

Papakostas, Thanos D; Yonekawa, Yoshihiro; Wu, David; Miller, John B; Veldman, Peter B; Chee, Yewlin E; Husain, Deeba; Eliott, Dean



An unusual diagnosis of splenic rupture.  


A 22-year-old woman presented with a 3-day history of worsening epigastric pain, non-productive cough and vomiting. On examination she was pale and had abdominal tenderness predominant in the right upper quadrant. Abdominal ultrasound excluded the presence of gall stones, but was unable to rule out free fluid in the abdomen. CT demonstrated extensive high-density ascites; however, no source of bleeding could be demonstrated. Clinically the patient's condition deteriorated, and an exploratory laparotomy was performed. In theatre the splenic capsule was found to have detached from the splenic body and emergency splenectomy was performed. Virology serology later demonstrated acute cytomegalovirus (CMV) infection, although tissue microscopy and CMV staining were negative. No other cause of rupture was found. The interesting aspects of this case include the poor correlation between initial presenting symptoms and subsequent diagnosis, the difficulty encountered in making a firm diagnosis and the atypical cause of rupture. PMID:25293683

Roche, Matthew; Maloku, Fatmir; Abdel-Aziz, Tarek Ezzat



Premature rupture of the membranes: neonatal consequences.  


Premature rupture of the membranes (PROM), membrane rupture before the onset of labor, occurs in 2% to 18% of pregnancies. The time from PROM to delivery (latency) is usually less than 48 hours in term pregnancy. Therefore, the risks of PROM at term are related to fetal distress, prolapsed cord, abruptio placenta, and rarely, infection. Preterm PROM (pPROM), PROM before 37 weeks' gestation, accounts for 20% to 40% of PROM, and the incidence is doubled in multiple gestations. The latency period in pPROM is inversely related to the gestational age thereby increasing the risks of oligohydramnios and infection in very premature infants and their mothers. Because pPROM is associated with 30% to 40% of premature births, pPROM is also responsible for the neonatal problems resulting from prematurity. This review examines the impact of PROM on the neonate including fetal distress, prematurity, infection, pulmonary hypoplasia, and restriction deformations. PMID:8912991

Merenstein, G B; Weisman, L E



Adherence of plaque components to different restorative materials.  


This study compared the amount of artificial plaque synthesized in vitro by Streptococcus sobrinus on various dental materials using radioisotopes. In particular, plaque-retaining capacities of new types of ceramics were the focus of this study. Specimens were fabricated from the following materials (one amalgam alloy [Spherical-D], one casting gold alloy [Casting Gold TYPE I], one resin composite [Herculite XR] and three ceramics [Vita Celay Blanks, IPS Empress and Dicor MGC]). The amount of bacteria and glucans adhered on the specimens was measured after incubation for 24 hours at 37 degrees C with radio-labeled cariogenic bacteria and sucrose. This adhesion test was performed using two different surfaces with 600-grit roughness and clinical smoothness. Irrespective of the surface roughness, the least amount of plaque adhered to the ceramics. However, in the case of the resin composite and amalgam, the amount of bacteria and glucan adhesion decreased dramatically by polishing, though there were no statistically different changes in the amount of bacteria and glucans that adhered to the ceramics even after polishing. In general, the amount of adhered bacteria showed almost the same tendency as that of glucans. Although no statistical differences in the amount of bacteria and glucan adhesion were detected among the three ceramics investigated in this study, a lesser amount of bacteria and glucans adhered to them compared to the other materials. PMID:11504440

Kawai, K; Urano, M



Patient specific multiscale modelling for plaque formation and progression.  


We present a three-dimensional model of plaque formation and progression that was tested in a set of patients who underwent coronary Computed Tomography angiography (CTA) for anginal symptoms. The 3D blood flow is described by the Navier-Stokes equations, together with the continuity equation. Mass transfer within the blood lumen and through the arterial wall is coupled with the blood flow and is modeled by a convection-diffusion equation. The Low Density Lipoprotein (LDL) transports in lumen of the vessel and through the vessel tissue (which has a mass consumption term) are coupled by Kedem-Katchalsky equations. The inflammatory process is modeled using three additional reaction-diffusion partial differential equations. A full three-dimensional model was created. Furthermore, features potentially affecting plaque growth, such as patient risk score, circulating biomarkers, localization and composition of the initial plaque, and coronary vasodilating capability were also investigated. The proof of concept of the model effectiveness was assessed 6 months after the baseline evaluation. PMID:23366529

Exarchos, T P; Sakellarios, A; Siogkas, P K; Fotiadis, D I; Milosevic, Z; Nikolic, D; Filipovic, N; Marraccini, P; Vozzi, F; Parodi, O



Supragingival plaque microbial analysis in reflection to caries experience  

PubMed Central

Background Dental caries develops as a result of the metabolism of carbohydrates by cariogenic bacteria present in a complex biofilm. The present study aimed to examine if bacteria in pooled supragingival plaque samples quantified using a “checkerboard DNA-DNA hybridization” based panel of caries-related bacteria, could reflect the caries experience in a manner similar to saliva samples analysed using a chair-side method in a previous investigation. Methods A total of 86 mothers and their children aged 4–6 years and 12–16 years old participated. Caries experience (DMFT/dmft; Decayed, Missing and Filled Teeth for permanent and primary teeth) was registered clinically and radiographically. Caries was recorded at the D3 level (caries into dentine). The D/d component was divided into three categories. A pooled supragingival plaque sample per participant was obtained from posterior approximal sites. Analyses of 15 bacterial species were performed using the checkerboard DNA-DNA hybridisation technique. Results No significant relationships were found between the bacterial scores and DMFT/dmft nor D/d groups. Conclusions Unlike the saliva samples and the chair-side method, interproximal pooled plaque samples analysed using the “checkerboard DNA-DNA hybridization technique” did not reveal any significant relations between the bacterial counts and the caries experience. PMID:23298235



The effect of two toothpastes on plaque and gingival inflamation.  


In this study on 60 adult subjects, the effective of Parodontax, a dentifrice containing herbal ingredients and sodium bicarbonate abrasive, was compared to a non-marketed new toothpaste containing herbal ingredients and calcium hydrogen phosphate as the abrasive. Plaque, gingivitis and gingival bleeding parameters were scored. The periodontal probe bleeding index of Ainamo and Bay was modified to score slight and moderate bleeding. In this first four-week period all subjects used the new toothpaste. After this period the new toothpaste produced a significant decrease (p<0.01) in gingivitis and bleeding on probing, but no effect on plaque was observed. During the second period of eight weeks the subjects were randomly divided into two groups, one using Parodontax and the other group continuing with the new toothpaste. The study design was a double-blind procedure. At the end of the 12-week study period the plaque index showed no changes in both groups. The gingivitis and bleeding indices decreased significantly (p<0.001) by 40% in both groups compared to the baseline examination. PMID:8624228

Saxer, U P; Menghini, G; Bohnert, K J; Ley, F



Sphenoid Wing en plaque meningiomas: Surgical results and recurrence rates  

PubMed Central

Background: Sphenoid wing en plaque meningiomas are a subgroup of meningiomas defined by its particular sheet-like dural involvement and its disproportionately large bone hyperostosis. En plaque meningiomas represent 2-9% of all meningiomas and they are mainly located in the sphenoid wing. Total surgical resection is difficult and therefore these tumors have high recurrence rates. Methods: Eighteen patients with sphenoid wing en plaque meningiomas surgically treated between January 1998 and December 2008 were included. Clinical, surgical, and follow-up data were retrospectively analyzed. Results: Mean age was 52.2 years and 83% were female. Five patients presented extension of dural component into the orbit and six patients presented cavernous sinus infiltration. Adjuvant radiation therapy was performed in three patients. After a mean follow-up of 4.6 years, five patients developed tumor recurrence - two patients were submitted to surgical treatment and the other three were submitted to radiation therapy. No patient presented recurrence after radiation therapy, whether performed immediately in the postoperative period or performed after recurrence. Patients without tumor extension to cavernous sinus or orbital cavity have the best prognosis treated with surgery alone. When tumor extension involves these locations the recurrence rate is high, especially in cases not submitted to adjuvant radiation therapy. Conclusion: Cavernous sinus and superior orbital fissure involvement are frequent and should be considered surgical limits. Postoperative radiation therapy is indicated in cases with residual tumor in these locations. PMID:23956929

Simas, Nuno M.; Farias, Joao Paulo



Traumatic dislocation of testes and bladder rupture.  


Traumatic dislocation of the testes with bladder rupture occurred in 2 multiply injured patients with pelvic fracture. One had a history of retractile testes and the other of previous testicular dislocation. Surgical correction was performed after closed reduction failed. These injuries must be recognized and treated promptly to maximize the likelihood of testicular salvage. If early intervention is not possible, duplex ultrasonography and pulsed Doppler analysis are the optional valuative studies. PMID:1466102

Lee, J Y; Cass, A S; Streitz, J M



[Splenic artery rupture in pancreatic pseudocyst].  


Hemorrhage is one of the most threatening complication of pancreatic pseudocyst. It results from erosion of adjacent vessels. Splenic, gastroduodenal, pancreaticoduodenal and middle colic vessels are predominantly involved. Hemorrhage may present different feature: intra and/or extraperitoneal collection, gastrointestinal bleeding. The authors report the rupture of splenic artery into pseudocyst, with the formation of pulsating pseudoaneurysm, increasing progressively until the final rupture. For the diagnosis the authors utilized: ultrasounds (US) which showed the cyst but not its nature and content; the CT scan which disclosed haematic contents; finally the US Color Doppler which proved the dynamic feature of hemorrhage. This technique allows to identify the arterious or venous source of bleeding and the possible presence of arteriovenous fistula. Arteriography was not performed due to circumstances, although it would permit bleeding vessel embolization and the control of hemorrhage. This procedure is not ever achievable, and doesn't exclude the possibility of rebleeding. On surgery, since the intraoperative rupture of the pseudoaneurysm occurred with severe hypovolemic shock, only a timely posterior mesogastric mobilization and the medially displacement of spleen-body-tail pancreatic complex, allowed to clamp the mass and the hemostasis. When such lesion are approached, it is mandatory to be prepared to carry on this maneuver: the severity of bleeding cannot allow intracystic ligature of bleeding vessel. PMID:10920499

Ungania, S; Panocchia, N



Biosensing using rupture event scanning (REVS)™  

NASA Astrophysics Data System (ADS)

We have developed a sensitive and economical method to detect analytes directly. The technique, which we term rupture event scanning (REVS™), is based on rapidly oscillating an acoustic wave device on which the analytes have been captured. As the magnitude of oscillation of the surface of the acoustic wave device is increased, there is increasing acceleration of adherent analytes. This in turn results in a larger force exerted by the surface on the particle, that ultimately causes rupture of the bonds attaching the particle to the surface. Using the same device, we can very sensitively monitor the excitation of vibrations in the acoustic wave device produced by bond rupture, which are then converted into an electrical signal. The signal indicates not only the presence of specifically bound analytes and their affinity for the receptor, but also the number of analytes present. The method works in air, water and complex biological fluids, is quantitative over at least six orders of magnitude of particle titre, and in affinity from sub-mM to pM. For selected analyte-receptor systems the sensitivity can be as low as 80 fg mm-2 (8 × 10-14 g mm-2). In this paper an example application of REVS™ is presented and the physical forces involved in the process are discussed.

Cooper, Matthew A.



Operative intra-aortic balloon rupture.  


Rupture of an intra-aortic balloon (IAB), inserted to assist in weaning from cardiopulmonary bypass, occurred during attempted intra-aortic administration of protamine in a 71-year-old male who later died. Intra-aortic balloon counterpulsation (IABC) is most commonly utilized to assist in weaning from cardiopulmonary bypass (CPB) or to augment low-flow states following CPB. In-hospital survival following IAB insertion in these circumstances in patients with coronary artery disease is approximately 60 per cent. Patients with valvular disease have a lower in-hospital survival rate (50 per cent). Complications of IABC are usually of vascular or infectious origin. Balloon rupture is a rare though potentially lethal complication. The effects of balloon rupture may be compounded by the use of helium as a driving gas to inflate the balloon. Intra-aortic administration of protamine has not been shown to be superior to peripheral administration and should be avoided if an IAB is in place. PMID:3383321

Finegan, B A; Comm, D G



Single Event Gate Rupture in EMCCD technology  

NASA Astrophysics Data System (ADS)

The high electric fields (typically 3 MV/cm2 interpoly field) utilised in Electron Multiplying Charged Coupled Devices (EMCCDs) reveal a potential vulnerability from Single Event Phenomena (SEP), in particular Single Event Gate Rupture (SEGR). SEGR is where a conduction path between two conductive areas of the CCD is produced, causing device failure. If EMCCDs are to be used for space applications the susceptibility to these events needs to be explored. A positive result from such an investigation can increase the technology readiness level of the device moving it another step closer to being used in space. Testing undertaken at the CYClotron of LOuvain la NEuve (CYCLONE), using the Heavy Ion Facility (HIF), conclusively showed EMCCD technology to have resilience to heavy ions that surpassed initial expectations. The simulations undertaken prior to experiment suggested gate rupture would occur at 20-40 MeV cm2/mg, however Linear Energy Transfers (LETs) greater than 100 MeV cm2/mg proved to not cause a rupture event. Within the radiation belts heavy ions with an LET greater than 60 MeV cm2/mg are not very common when compared to the fluxes used at the HIF. Possible reasons for this result are discussed in this work, leading to a conclusion that EMCCD technology is a secure choice for space flight.

Evagora, A. M.; Murray, N. J.; Holland, A. D.; Burt, D.



Ruptured Corpus Luteal Cyst: CT Findings  

PubMed Central

Objective To evaluate the CT findings of ruptured corpus luteal cysts. Materials and Methods Six patients with a surgically proven ruptured corpus luteal cyst were included in this series. The prospective CT findings were retrospectively analyzed in terms of the size and shape of the cyst, the thickness and enhancement pattern of its wall, the attenuation of its contents, and peritoneal fluid. Results The mean diameter of the cysts was 2.8 (range, 1.5-4.8) cm; three were round and three were oval. The mean thickness of the cyst wall was 4.7 (range, 1-10) mm; in all six cases it showed strong enhancement, and in three was discontinuous. In five of six cases, the cystic contents showed high attenuation. Peritoneal fluid was present in all cases, and its attenuation was higher, especially around the uterus and adnexa, than that of urine present in the bladder. Conclusion In a woman in whom CT reveals the presence of an ovarian cyst with an enhancing rim and highly attenuated contents, as well as highly attenuated peritoneal fluid, a ruptured corpus luteal cyst should be suspected. Other possible evidence of this is focal interruption of the cyst wall and the presence of peritoneal fluid around the adnexa. PMID:12679633

Choi, Hyuck Jae; Kim, Sun Ho; Kim, Hyo-Cheol; Park, Chang Min; Lee, Hak Jong; Moon, Min Hoan; Jeong, Jun Yong



[Diagnosis and treatment of diaphragm traumatic ruptures].  


29 patients with traumatic ruptures of left cupola of the diaphragm were studied. Pain, dispnoe, tachycardia more intensive after a meal due to repletion and dislocation of the stomach into pleural cavity and its pressure on the organs of the mediastinum were the main symptoms of the disease. The diagnosis of traumatic rupture of the diaphragm was made on the base of clinical and roentgenological examination. In the acute period of trauma the diagnosis is difficult, especially in combined trauma. In 92.3% of cases the stomach and the bowel move into the pleural cavity, which may simulate pneumothorax or relaxation of the diaphragm. Contrast examination of the gastro-intestinal tract and pleural puncture help in differential diagnosis. All the cases of traumatic ruptures of the diaphragm should be subjected to surgical treatment. Urgent operation is indicated in continuing bleeding, incarceration of organs, acute cardiopulmonary insufficiency due to the collapse of the lung and dislocation of mediastinal organs of into contralateral position. Thoracotomy in VII intercostal space is considered as a valid approach. There were 2 (6.9%) lethal outcomes after 29 operations. Long-term results are quite favourable. PMID:10459187

Gadzhiev, Sh M; Gurbanaliev, I G; Abbasov, F; Mamedov, A S; Ze?nalov, N D; Iusifov, I A



Modelling prevalence and incidence of fibrosis and pleural plaques in asbestos-exposed populations for screening and follow-up: a cross-sectional study  

PubMed Central

Background CT-Scan is currently under assessment for the screening of asbestos-related diseases. However, to date no consensus exists as to how to select high-risk asbestos-exposed populations suitable for such screening programs. The objective of this study is to select the most relevant exposure variables for the prediction of pleural plaques and asbestosis in order to guide clinicians in their use of CT-Scan. Methods A screening program of non malignant asbestos-related diseases by CT-scan was conducted among asbestos-exposed volunteers in France. Precise assessments of asbestos exposure were obtained by occupational hygiene measurements and a job-exposure matrix. Several parameters were calculated (time since first exposure, duration, intensity and cumulative exposure to asbestos). Predictive parameters of prevalence and incidence were then estimated by standard logistic and a complementary log-log regression models. Results 1011 subjects were recruited in this screening program among them 474 (46.9%) presented with pleural plaques and 61 (6.0%) with interstitial changes compatible with asbestosis on CT-scan. Time since first exposure (p < 0.0001) and either cumulative or mean exposure (p < 0.0001) showed independent associations with both pleural plaques and asbestosis prevalence and pleural plaques incidence. Modelling incidence of pleural plaques showed a 0.8% to 2.4% yearly increase for a mean exposure of 1 f/ml. Conclusion Our findings confirmed the role played by time since first exposure and dose but not duration in asbestos-related diseases. We recommend to include these parameters in high-risk populations suitable for screening of these diseases. Short-periodicity of survey of pleural plaques by CT-Scan seemed not to be warranted. PMID:18570653

Paris, Christophe; Martin, Aurelie; Letourneux, Marc; Wild, Pascal



Liver Hydatid Cyst with Transdiaphragmatic Rupture and Lung Hydatid Cyst Ruptured into Bronchi and Pleural Space  

SciTech Connect

The aim of this case study is to present effectiveness of percutaneous drainage as a treatment option of ruptured lung and liver hydatid cysts. A 65-year-old male patient was admitted with complicated liver and lung hydatid cysts. A liver hydatid cyst had ruptured transdiaphragmatically, and a lung hydatid cyst had ruptured both into bronchi and pleural space. The patient could not undergo surgery because of decreased respiratory function. Both cysts were drained percutaneously using oral albendazole. Povidone-iodine was used to treat the liver cyst after closure of the diaphragmatic rupture. The drainage was considered successful, and the patient had no recurrence of signs and symptoms. Clinical, laboratory, and radiologic recovery was observed during 2.5 months of catheterization. The patient was asymptomatic after catheter drainage. No recurrence was detected during 86 months of follow-up. For inoperable patients with ruptured liver and lung hydatid cysts, percutaneous drainage with oral albendazole is an alternative treatment option to surgery. The percutaneous approach can be life-saving in such cases.

Ar Latin-Small-Letter-Dotless-I bas, Bilgin Kadri, E-mail:; Dingil, Guerbuez [A.Y. Ankara Oncology Training and Research Hospital, Department of Radiology (Turkey); Koeroglu, Mert [Sueleyman Demirel University School of Medicine, Department of Radiology (Turkey); Uenguel, Uemit; Zaral Latin-Small-Letter-Dotless-I , Aliye Ceylan [A.Y. Ankara Oncology Training and Research Hospital, Department of Radiology (Turkey)



Pravastatin Treatment Increases Collagen Content and Decreases Lipid Content, Inflammation, Metalloproteinases, and Cell Death in Human Carotid Plaques Implications for Plaque Stabilization  

Microsoft Academic Search

Background—The clinical benefits of lipid lowering with statins are attributed to changes in plaque composition leading to lesion stability, but supporting clinical data from human studies are lacking. Therefore, we investigated the effect of 3 months of pravastatin treatment on composition of human carotid plaques removed during carotid endarterectomy. Methods and Results—Consecutive patients with symptomatic carotid artery stenosis received 40

Milita Crisby; Gunilla Nordin-Fredriksson; Prediman K. Shah; Juliana Yano; Jenny Zhu; Jan Nilsson


The Relationship Between Plaque pH, Plaque Acid Anion Profiles, and Oral Carbohydrate Retention After Ingestion of Several 'Reference Foods' by Human Subjects  

Microsoft Academic Search

The primary aim of this study was to rank several reference foods (apple drink, caramel, chocolate, cookie, skimmed milk powder, snack cracker, and wheat flake) according to their plaque pH response as monitored in a panel of 12 volunteers by the plaque-sampling method for comparison with data previously reported with other methods used to assess cariogenicity potential. Secondary experiments (using

M. W. J. Dodds; W. M. Edgar



Spectral CT imaging of vulnerable plaque with two independent biomarkers  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to investigate the feasibility of a novel four-material decomposition technique for assessing the vulnerability of plaque with two contrast materials spectral computer tomography (CT) using two independent markers: plaque's inflammation and spotty calcification. A simulation study was conducted using an energy-sensitive photon-counting detector for k-edge imaging of the coronary arteries. In addition to detecting the inflammation status, which is known as a biological marker of a plaque's vulnerability, we use spotty calcium concentration as an independent marker to test a plaque's vulnerability. We have introduced a new method for detecting and quantifying calcium concentrations in the presence of two contrast materials (iodine and gold), calcium and soft tissue background. In this method, four-material decomposition was performed on a pixel-by-pixel basis, assuming there was an arbitrary mixture of materials in the voxel. The concentrations of iodine and gold were determined by the k-edge material decomposition based on the maximum likelihood method. The calibration curves of the attenuation coefficients, with respect to the concentrations of different materials, were used to separate the calcium signal from both contrast materials and different soft tissues in the mixtures. Three different materials (muscle, blood and lipid) were independently used as soft tissue. The simulations included both ideal and more realistic energy resolving detectors to measure the polychromatic photon spectrum in single slice parallel beam geometry. The ideal detector was used together with a 3 cm diameter digital phantom to demonstrate the decomposition method while a more realistic detector and a 33 × 24 cm2 digital chest phantom were simulated to validate the vulnerability assessment technique. A 120 kVp spectrum was generated to produce photon flux sufficient for detecting contrast materials above the k-edges of iodine (33.2 keV) and gold (80.7 keV). By performing simulations on a 3 cm diameter digital phantom, we successfully identified four materials that were simultaneously present in the mixture at different proportions and in multiple locations on the phantom. Quantitative analysis with a chest digital phantom showed that the results for iodine, gold and calcium were highly correlated with the known concentrations. The analysis revealed a potentially powerful technique for assessing a plaque's vulnerability with two independent markers. High correlation and low relative errors between calculated and known materials’ concentrations showed that the method is feasible. This technique can potentially have a high clinical impact.

Baturin, Pavlo; Alivov, Yahya; Molloi, Sabee



Spectral CT imaging of vulnerable plaque with two independent biomarkers.  


The purpose of this paper is to investigate the feasibility of a novel four-material decomposition technique for assessing the vulnerability of plaque with two contrast materials spectral computer tomography (CT) using two independent markers: plaque's inflammation and spotty calcification. A simulation study was conducted using an energy-sensitive photon-counting detector for k-edge imaging of the coronary arteries. In addition to detecting the inflammation status, which is known as a biological marker of a plaque's vulnerability, we use spotty calcium concentration as an independent marker to test a plaque's vulnerability. We have introduced a new method for detecting and quantifying calcium concentrations in the presence of two contrast materials (iodine and gold), calcium and soft tissue background. In this method, four-material decomposition was performed on a pixel-by-pixel basis, assuming there was an arbitrary mixture of materials in the voxel. The concentrations of iodine and gold were determined by the k-edge material decomposition based on the maximum likelihood method. The calibration curves of the attenuation coefficients, with respect to the concentrations of different materials, were used to separate the calcium signal from both contrast materials and different soft tissues in the mixtures. Three different materials (muscle, blood and lipid) were independently used as soft tissue. The simulations included both ideal and more realistic energy resolving detectors to measure the polychromatic photon spectrum in single slice parallel beam geometry. The ideal detector was used together with a 3 cm diameter digital phantom to demonstrate the decomposition method while a more realistic detector and a 33 × 24 cm(2) digital chest phantom were simulated to validate the vulnerability assessment technique. A 120 kVp spectrum was generated to produce photon flux sufficient for detecting contrast materials above the k-edges of iodine (33.2 keV) and gold (80.7 keV). By performing simulations on a 3 cm diameter digital phantom, we successfully identified four materials that were simultaneously present in the mixture at different proportions and in multiple locations on the phantom. Quantitative analysis with a chest digital phantom showed that the results for iodine, gold and calcium were highly correlated with the known concentrations. The analysis revealed a potentially powerful technique for assessing a plaque's vulnerability with two independent markers. High correlation and low relative errors between calculated and known materials' concentrations showed that the method is feasible. This technique can potentially have a high clinical impact. PMID:22683885

Baturin, Pavlo; Alivov, Yahya; Molloi, Sabee



The importance of hemorrhage in the relationship between gross morphologic characteristics and cerebral symptoms in 376 carotid artery plaques.  

PubMed Central

In a prospective study 376 carotid artery plaques (275 symptomatic, 101 asymptomatic) were obtained from endarterectomies (184 unilateral and 96 bilateral) in 280 patients. The gross morphologic features of each plaque were noted at surgery and, together with the patient's clinical history, stored in computer memory. These data were analyzed in order to investigate the relationship of gross morphologic plaque characteristics with both the presence of cerebral symptoms and the degree of stenosis associated with the plaque. Ulceration was the most frequently observed of the five major gross plaque morphologic characteristics (46.0% of all plaques), but only intramural hemorrhage (30.6% of all plaques) was significantly more common in all symptomatic compared with all asymptomatic plaques (p less than 0.02). Hemorrhage was also the only gross characteristic significantly more common in focal symptomatic plaques when compared with either asymptomatic plaques (p less than 0.05) or nonfocal symptomatic plaques (p less than 0.01). When all the plaques were divided into three broad degrees of stenosis groups (0-39%, 40-69%, 70-99%) on the basis of angiographic data, only hemorrhage showed a significant correlation in incidence with increased degree of plaque stenosis, both when all plaques were considered (p less than 0.001) and when only symptomatic plaques were examined (p less than 0.001). The results indicate that intramural hemorrhage is the only carotid plaque gross morphologic characteristic significantly more frequent in symptomatic compared with asymptomatic plaques and the only characteristic significantly correlated with increased plaque size. These findings indicate that factors other than plaque ulceration and intraluminal thrombus play an important role in carotid plaque related cerebral symptoms. The data also raise questions concerning the unequivocal value of anticoagulant therapy in carotid artery disease, especially in highly stenotic lesions. Images Fig. 1. Fig. 1. PMID:6824372

Imparato, A M; Riles, T S; Mintzer, R; Baumann, F G



Retention of antimicrobial activity in plaque and saliva following mouthrinse use in vivo.  


The aim of this study was to determine the contribution of plaque and saliva towards the prolonged activity, also called substantivity, of three antimicrobial mouthrinses (Listerine®, Meridol®, Crest Pro Health®), used in combination with a toothpaste (Prodent Coolmint®). Volunteers brushed for 4 weeks with a toothpaste without antimicrobial claims, while during the last 2 weeks half of the volunteers used an antimicrobial mouthrinse in addition to brushing. At the end of the experimental period, plaque and saliva samples were collected 6 h after oral hygiene, and bacterial concentrations and viabilities were determined. The contribution of plaque and saliva towards substantivity was assessed by combining plaque obtained after mechanical cleaning only with plaque and saliva obtained after additional use of an antimicrobial rinse. Subsequently, resulting viabilities of the combined plaques were determined. The viabilities of plaque samples after additional rinsing with mouthrinses were lower than of plaque obtained after mechanical cleaning only, regardless of the rinse involved. Moreover, plaque collected 6 h after rinsing with antimicrobial mouthrinses contained a surplus of antimicrobial activity. Only Listerine showed decreased viability in saliva, but none of the mouthrinses showed any residual antimicrobial activity in saliva. The findings indicate that plaque left behind after mechanical cleaning contributes to the prolonged substantivity of antimicrobial mouthrinses. PMID:20838045

Otten, M P T; Busscher, H J; van der Mei, H C; Abbas, F; van Hoogmoed, C G



Dosimetric effect of source centering and residual plaque for beta-emitting catheter based intravascular brachytherapy sources.  


Catheter-based radiation delivery systems employing both beta-particle and gamma-ray emitters are currently being investigated for their efficacy in addressing restenosis following percutaneous coronary intervention (PCI). The dosimetric consequences of source centering within the arterial lumen and presence of residual plaque are potentially important issues for the uniform delivery of dose to the arterial tissue. In this study, we have examined the effect of source centering on the resulting dose to the arterial wall from clinical intravascular brachytherapy sources containing 32P and 90Sr/Y90. Monte Carlo simulations using the MCNP code were performed for these catheter-based sources with offsets of 0.5 mm and 1 mm from the center of the arterial lumen in homogenous water medium as well as in the presence of residual plaque. Three different positions were modeled and the resulting dose values were analyzed to assess their impact on the resulting dose distribution. The results indicate a variation ranging from -40% to +70% for 32P source and -30% to +50% for 90Sr/90Y at a radial distance of 2 mm from the center of the coronary artery, relative to the dose from a centered source, for a 0.5 mm offset. The variation for a 1 mm offset ranges from -65% to +182% for 32P source and to -50% to +140% for 90Sr/90Y. A concentric residual plaque layer was also modeled so as to assess the combined influence of offset and residual plaque on the dosimetry. Finally the effect of cardiac motion and its potential impact on catheter position and hence the dose distribution is also examined by considering two separate cases of catheter displacement. The results indicate that dose variations range between -28% to +91% when it is assumed that cardiac motion causes catheter movement during coronary lesion irradiation. PMID:11695779

Sehgal, V; Li, Z; Palta, J R; Bolch, W E



Estrogen protects against intracranial aneurysm rupture in ovariectomized mice.  


Clinical observations suggest that postmenopausal women have a higher incidence of aneurysmal rupture than premenopausal women. We hypothesize that a relative deficiency in estrogen may increase the risks of aneurysmal growth and subarachnoid hemorrhage in postmenopausal women. We assessed the effects of estrogen and selective estrogen receptor subtype agonists on the development of aneurysmal rupture in ovariectomized female mice. We used an intracranial aneurysm mouse model that recapitulates the key features of human intracranial aneurysms, including spontaneous rupture. Ten- to 12-week-old ovariectomized female mice received treatment with estrogen, nonselective estrogen receptor antagonist, estrogen receptor-? agonist, or estrogen receptor-? agonist starting 6 days after aneurysm induction so that the treatments affected the development of aneurysmal rupture without affecting aneurysmal formation. Estrogen significantly reduced the incidence of ruptured aneurysms and rupture rates in ovariectomized mice. Nonselective estrogen receptor antagonist abolished the protective effect of estrogen. Although estrogen receptor-? agonist did not affect the incidence of ruptured aneurysms or rupture rates, estrogen receptor-? agonist prevented aneurysmal rupture without affecting the formation of aneurysms. The protective role of estrogen receptor-? agonist was abolished by the inhibition of nitric oxide synthase. We showed that estrogen prevented aneurysmal rupture in ovariectomized female mice. The protective effect of estrogen seemed to occur through the activation of estrogen receptor-?, a predominant subtype of estrogen receptor in human intracranial aneurysms and cerebral arteries. PMID:24732889

Tada, Yoshiteru; Wada, Kosuke; Shimada, Kenji; Makino, Hiroshi; Liang, Elena I; Murakami, Shoko; Kudo, Mari; Shikata, Fumiaki; Pena Silva, Ricardo A; Kitazato, Keiko T; Hasan, David M; Kanematsu, Yasuhisa; Nagahiro, Shinji; Hashimoto, Tomoki



Diffuse senile plaques occur commonly in the cerebellum in Alzheimer's disease.  

PubMed Central

Diffuse senile plaques are characterized by the presence of beta protein (beta P), also called A4 protein, in a dispersed form and the apparent lack of associated dystrophic neurites or reactive glial cells. They are the most common type of senile plaque found in the cerebral cortex in Alzheimer's disease (AD), Down's syndrome (DS), and normal aging. Here is reported the frequent presence of diffuse senile plaques in the molecular layer of cerebellar cortex in AD. Typical neuritic plaques were never detected in this location, making the cerebellar molecular cortex a useful site for the study of diffuse plaques because diffuse plaques in the cerebral cortex are intermingled with neuritic plaques. Diffuse cerebellar plaques were detected by modified Bielschowsky silver stain in 47 of 100 cases of clinically and pathologically diagnosed AD and in none of 40 aged demented and nondemented controls. They were immunolabeled by antibodies to purified AD meningeal or cortical beta P, and to a synthetic beta P but not by two antibodies to the carboxyl- and amino-termini of the beta protein precursor (beta PP), which label a subgroup of cerebral cortical plaques. This latter result suggests that the beta P deposited in the cerebellar molecular layer may be derived from a form of the beta PP from which the carboxyl and amino terminal regions of the precursor have already been cleaved. Diffuse cerebellar plaques were not recognized by antibodies to neurofilaments, tau, and PHF, all of which detect dystrophic neurites in cerebral cortical neuritic plaques. Also, no association of reactive astrocytes or microglial cells with diffuse cerebellar plaques was observed. Thus, diffuse cerebellar plaques represent multifocal deposits of noncompacted beta P that cause little or no morphologic reaction in their microenvironment. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:2675616

Joachim, C. L.; Morris, J. H.; Selkoe, D. J.



Rosuvastatin improves plaque morphology in cerebral embolism patients with normal low-density lipoprotein and severe aortic arch plaque.  


The effect of rosuvastatin was investigated on complicated aortic arch plaque (CAP) morphology and lipid profiles in acute cerebral embolism (CE) patients with normal low-density lipoprotein-cholesterol (LDL-c) levels. Transesophageal echocardiography (TEE) studies were performed in 56 consecutive CE patients with LDL-c less than 140 mg/dL who were not taking lipid-lowering agents at baseline. CAP observed by TEE was defined as the presence of greater than 4-mm diameter, ulcerated, or mobile aortic plaque. Patients were divided into those with CAP versus without CAP (group A, n=24, age 69±8 years) and without CAP (group B, n=32, age 62±10 years). Of the 24 group A patients, 18 received 5 mg/d of rosuvastatin for 6 months and had follow-up TEE studies. In Group A, the baseline values of high-density lipoprotein-cholesterol (HDL-c) and apolipoprotein A-1 (ApoA-1) were significantly lower than in Group B (44±15 versus 55±15 mg/dL, P=.0059; 103±19 versus 137±25 mg/dL, P=.0006, respectively) and age and serum high-sensitivity C-reactive protein concentration were significantly higher (69±8 vs. 62±10 years, P=.0080; 2.34±3.05 vs. 0.67±1.00 mg/dL, P=.0054, respectively). By multivariate logistic regression analysis, ApoA-1 was shown to be an independent predictor of CAP (odds ratio=.894, 95% confidence intervals .800-.996, P=.0483). In the 18 group A patients receiving rosuvastatin for 6 months, aortic arch plaque diameter and serum LDL-c were significantly decreased (5.8±2.2 to 5.1±2.1 mm, P=.0377; 110±23 to 81±23 mg/dL, P=.0008, respectively), whereas serum HDL-c and ApoA-1 concentrations were significantly increased (42±8 to 52±9 mg/dL, P=.0002; 109±22 to 135±15 mg/dL, P=.0002, respectively). Plaques were morphologically improved in 11 patients, unchanged in 6, and worsened in 1. These data suggest that rosuvastatin improves plaque morphology concomitant with improving lipid profiles in CE patients with normal LDL-c levels. PMID:24739590

Kaneko, Kazuyoshi; Saito, Hiroki; Takahashi, Tetsuya; Kiribayashi, Nobuyuki; Omi, Koki; Sasaki, Toshiki; Niizeki, Takeshi; Sugawara, Shigeo; Akasaka, Masahiro; Kubota, Isao



Positron emission tomography radioligands for in vivo imaging of A? plaques  

PubMed Central

The development of positron emission tomography (PET) radioligands for the non-invasive imaging of amyloid-? plaque burden has been the focus of intense research efforts over the last decade. A variety of structural backbones have been investigated and several radiolabeled molecules have been evaluated in phase I (and later) clinical studies. These efforts have been driven by the desire not only to develop a suitable diagnostic imaging agent but also to develop a means to evaluate potential therapies for Alzheimer’s disease. This review focuses on the development of these ligands, as well as the radiochemistry and current regulatory status of these PET radioligands. Particular attention is given to those ligands that have progressed to the later stages of drug development (phase II/III clinical trial studies) or approved New Drug Application status. PMID:24285314

Mason, N. Scott; Mathis, Chester A.; Klunk, William E.



Dynamics of three-dimensional thin film rupture  

NASA Astrophysics Data System (ADS)

We consider the problem of thin film rupture driven by van der Waals forces. A fourth-order nonlinear PDE governs the low Reynolds number lubrication model for a viscous liquid on a solid substrate. Finite-time singularities in this equation model rupture leading to formation of dry spots in the film. Our study addresses the problem of rupture in the full three-dimensional geometry. We focus on stability and selection of the dynamics determined by the initial conditions on small finite domains with planar and axisymmetric geometries. We also address the final stages of the dynamics - self-similar dynamics for point, line, and ring rupture. We will demonstrate that line and ring rupture are unstable and will generically destabilize to produce axisymmetric rupture at isolated points.

Witelski, Thomas P.; Bernoff, Andrew J.



Human Serum Albumin Cys34 Oxidative Modifications following Infiltration in the Carotid Atherosclerotic Plaque  

PubMed Central

Objectives. To evaluate if the prooxidant environment present in atherosclerotic plaque may oxidatively modify filtered albumin. Methods. Fluorescein-5-maleimide labelled plasma samples and plaque extracts from 27 patients who had undergone carotid endarterectomy were analysed through nonreducing SDS-PAGE for albumin-Cys34 oxidation. Furthermore, degree and pattern of S-thiolation in both circulating and plaque-filtered albumin were assayed. Results. Albumin filtered in the atherosclerotic plaque showed higher levels of Cys34 oxidative modifications than the corresponding circulating form as well as different patterns of S-thiolation. Conclusions. Data indicate that the circulating albumin, once filtered in plaque, undergoes Cys34 oxidative modifications and demonstrate for the first time that albumin is a homocysteine and cysteinylglycine vehicle inside the plaque environment. PMID:24738021

Zinellu, Angelo; De Muro, Pierina; Carru, Ciriaco; Spirito, Rita; Guarino, Anna



Characterization of atherosclerotic plaque-depositions by infrared, Raman and CARS microscopy  

NASA Astrophysics Data System (ADS)

Atherosclerotic plaques are mainly composed of proteoglycans, triglycerides, cholesterol, cholesterolester and crystalline calcium. From histopathological characterizations it is known that the composition of these atherosclerotic plaques can vary to a great extent, due to different risk factors as smoking, hyperlipedemia, or genetic background ect. The individual plaque components can be spectroscopically easily identified. Furthermore, spectroscopic imaging technologies offer the possibility to study the plaque compositions in a more quantitative manner than traditional staining techniques. Here, we compare the potential of IR, Raman and CARS microscopy to characterize the constitution of atherosclerotic plaques as well as the structure of the surrounding tissue. For data analysis and image reconstruction spectral decomposition algorithms such as vertex component analysis (VCA) were introduced. The results are in good agreement with the histopathology. Aim of the study is to correlate the compositional characteristics of atherosclerotic plaques with individual disease patterns.

Matthäus, Christian; Bergner, Gero; Krafft, Christoph; Dietzek, Benjamin; Romeike, Bernd F. M.; Brehm, Bernhard R.; Popp, Jürgen



Numbers and types of asbestos fibers in subjects with pleural plaques.  

PubMed Central

The authors analyzed asbestos fibers in lung samples from 20 subjects with pleural plaques discovered on autopsy and compared the findings to their previous analyses of lungs from subjects with little or no asbestos exposure and no plaques. Sixteen of the subjects with plaques had a history of exposure to asbestos. The authors used electron-optical methods and energy-dispersive x-ray spectroscopy to investigate the structure, diffraction patterns, and chemical composition of the asbestos fibers. The subjects with plaques had significantly higher median concentrations than the control subjects for amosite and crocidolite fibers (P less than 0.01) but not for the other fiber types. Minimal microscopic asbestosis was present in the 3 subjects who had the highest amosite concentrations. In the subjects with typical plaques, a history of asbestos exposure, and more fibers than in the control population, the relation of the plaques to asbestos was confirmed; for others, it was uncertain. PMID:7124907

Warnock, M. L.; Prescott, B. T.; Kuwahara, T. J.



Chronic Over-Expression of Heat Shock Protein 27 Attenuates Atherogenesis and Enhances Plaque Remodeling: A Combined Histological and Mechanical Assessment of Aortic Lesions  

PubMed Central

Aims Expression of Heat Shock Protein-27 (HSP27) is reduced in human coronary atherosclerosis. Over-expression of HSP27 is protective against the early formation of lesions in atherosclerosis-prone apoE?/? mice (apoE?/?HSP27o/e) - however, only in females. We now seek to determine if chronic HSP27 over-expression is protective in a model of advanced atherosclerosis in both male and female apoE?/? mice. Methods and Results After 12 weeks on a high fat diet, serum HSP27 levels rose more than 16-fold in male and female apoE?/?HSP27o/e mice, although females had higher levels than males. Relative to apoE?/? mice, female apoE?/?HSP27o/e mice showed reductions in aortic lesion area of 35% for en face and 30% for cross-sectional sinus tissue sections – with the same parameters reduced by 21% and 24% in male cohorts; respectively. Aortic plaques from apoE?/?HSP27o/e mice showed almost 50% reductions in the area occupied by cholesterol clefts and free cholesterol, with fewer macrophages and reduced apoptosis but greater intimal smooth muscle cell and collagen content. The analysis of the aortic mechanical properties showed increased vessel stiffness in apoE?/?HSP27o/e mice (41% in female, 34% in male) compare to apoE?/? counterparts. Conclusions Chronic over-expression of HSP27 is atheroprotective in both sexes and coincides with reductions in lesion cholesterol accumulation as well as favorable plaque remodeling. These data provide new clues as to how HSP27 may improve not only the composition of atherosclerotic lesions but potentially their stability and resilience to plaque rupture. PMID:23409070

Tremblay, Dominique; Rayner, Katey; McNulty, Melissa; Zhao, XiaoLing; Kennedy, Christopher R. J.; de BelleRoche, Jacqueline; Pelling, Andrew E.; O'Brien, Edward R.



Successful infarct exclusion for postinfarction left ventricular free wall rupture  

PubMed Central

The mortality of postinfarction left ventricular free wall rupture is still high. Several surgical techniques have been used for repairing such ruptures. Here, we describe using an infarction exclusion technique to successfully treat a case of a blow-out type postinfarction left ventricular free wall rupture. This technique has frequently been used for repairing postinfarction ventricular septal perforation. In this case, infarcted myocardial tearing was prevented, and complete haemostasis was achieved by infarct exclusion. PMID:23424241

Kato, Yasuyuki; Fukui, Toshihiro; Tabata, Minoru; Takanashi, Shuichiro



[Bilateral uterine rupture of an unscarred gravid uterus before labor].  


We report a case of bilateral spontaneous uterine rupture of an unscarred uterus occured in a primigravida at 32 weeks to take care in our department after in utero transfert. Uterine rupture occurs mainly on scarred uterus during labor. This is an unfrequent but serious complication involving fetal-maternal prognosis in the absence of immediate care. We are conducting a review about spontaneous uterine rupture of unscarred uterus, before and during labor. PMID:24394323

Leroux, M; Coatleven, F; Faure, M; Horovitz, J



Comparison of PCR and Plaque Assay for Detection and Enumeration of Coliphage in Polluted Marine Waters  

Microsoft Academic Search

the plaque assay and a reverse transcriptase (RT) PCR technique for F1-specific coliphage. The coliphage levels detected by the plaque assay averaged 1.90 3 104 PFU\\/100.0 ml. Using a most probable number (MPN) PCR approach, the levels averaged 2.40 3 106 MPN-PCR units\\/100.0 ml. Two samples were positive by RT-PCR but negative by plaque assay, and 12 samples were positive




Manganese and copper in the root plaque of Phragmites australis (cav. ) trin. ex steudel  

Microsoft Academic Search

Manganese and copper were found in the iron oxide plaque on roots of Phragmites australis collected at six sampling sites in southern Quebec and Ontario, Canada. Manganese concentration in the plaque, like that of Fe, is correlated with Mn-bound-to-carbonates fraction of the soil\\/sediment. The Fe:Mn ratio of the plaque resemble the same ratio of Fe:Mn-bound-to-carbonates in the substrate. The ratio




Membrane Type 1 Matrix Metalloproteinase Expression in Human Atherosclerotic Plaques Evidence for Activation by Proinflammatory Mediators  

Microsoft Academic Search

Background—Matrix metalloproteinases (MMPs) are expressed in atherosclerotic plaques, where in their active form, they may contribute to vascular remodeling and plaque disruption. In this study, we tested the hypothesis that membrane type 1 MMP (MT1-MMP), a novel transmembrane MMP that activates pro-MMP-2 (gelatinase A), is expressed in human atherosclerotic plaques and that its expression is regulated by proinflammatory molecules. Methods

Tripathi B. Rajavashisth; Xiao-Ping Xu; Stefan Jovinge; Simcha Meisel; Xiao-Ou Xu; Ning-Ning Chai; Michael C. Fishbein; Sanjay Kaul; Bojan Cercek; Behrooz Sharifi; Prediman K. Shah


Capturing Continental Rupture Processes in Afar  

NASA Astrophysics Data System (ADS)

Both continental and oceanic rifting processes are highly 3D, but the stability of the along-axis segmentation from rifting to breakup, and its relationship to seafloor spreading remains debated. Three-dimensional models of the interactions of faults and magmatism in time and space are in development, but modelling and observations suggest that magmatic segments may propagate and/or migrate during periods of magmatism. Our ability to discriminate between the various models in large part depends on the quality of data in the ocean-transition zone, or, observations from zones of incipient plate rupture. Largely 2D crustal-scale seismic data from magmatic passive margins reveal large magmatic additions to the crust, but the timing of this heat and mass transfer is weakly constrained. Thus, the lack of information on the across rift breadth of the deforming zone at rupture, and the relationship between the early rift segmentation and the seafloor spreading segmentation represent fundamental gaps in knowledge. Our study of Earth's youngest magmatic margin, the superbly exposed, tectonically active southern Red Sea, aims to answer the following questions: What are the geometry and kinematics of active fault systems across the 'passive margin' to zone of incipient plate rupture? What is the relationship between the initial border fault segmentation, and the breakup zone segmentation? What is the distribution of active deformation and magmatism, and how does it compare to time-averaged strain patterns? We integrate results of recent experiments that suggest widespread replacement of crust and mantle lithosphere beneath the 'passive' margin, and explain the ongoing seismic deformation as a consequence of bending stresses across the ocean-continent transition, with or without a dynamic component.

Ebinger, Cynthia; Belachew, Manahloh; Tepp, Gabrielle; Keir, Derek; Ayele, Atalay



Forecasting the Rupture Directivity of Large Earthquakes  

NASA Astrophysics Data System (ADS)

Forecasting the rupture directivity of large earthquakes is an important problem in probabilistic seismic hazard analysis (PSHA), because directivity strongly influences ground motions. We cast this forecasting problem in terms of the conditional hypocenter distribution (CHD), defined to be the probability distribution of a hypocenter given the spatial distribution of fault slip (moment release). The simplest CHD is a uniform distribution for which the hypocenter probability density equals the moment-release probability density. We have compiled samples of CHDs from a global distribution of large earthquakes using three estimation methods: (a) location of hypocenters within the slip distribution from finite-fault inversions, (b) location of hypocenters within early aftershock distributions, and (c) direct inversion for the directivity parameter D, defined in terms of the degree-two polynomial moments of the source space-time function. The data from method (a) are statistically inconsistent with the uniform CHD suggested by McGuire et al. (2002) using method (c). Instead, the data indicate a 'centroid-biased' CHD, in which the expected distance between the hypocenter and the hypocentroid is less than that of a uniform CHD; i.e., the directivities inferred from finite-fault models appear to be closer to bilateral than predicted by the uniform CHD. One source of this discrepancy may be centroid bias in the second-order moments owing to poor localization of the slip in finite-fault inversions. We compare these observational results with CHDs computed from a large set of theoretical ruptures in the Southern California fault system produced by the Rate-State Quake simulator (RSQSim) of Dieterich and Richards-Dinger (2010) and discuss the implications for rupture dynamics and fault-zone heterogeneities.

Donovan, J. R.; Jordan, T. H.



Migraine before rupture of intracranial aneurysms  

PubMed Central

Background Rupture of a saccular intracranial aneurysm (SIA) causes thunderclap headache but it remains unclear whether headache in general and migraine in particular are more prevalent in patients with unruptured SIA. Methods In a prospective case–control study 199 consecutive patients with SIA (103 females and 96 males, mean age: 43.2 years) received a semistructured face to face interview focusing on past headaches. All were admitted to hospital mostly because of rupture (177) or for unruptured aneurysm (22). In parallel we interviewed 194 blood donors (86 females, 108 males, mean age: 38.4 years). Diagnoses were made according to the International Headache Society criteria. Aneurysms were diagnosed by conventional cerebral angiography. Results During the year before rupture, 124 (62.3%) had one or more types of headache. These headaches included: migraine without aura (MO): 78 (39.2%), migraine with aura (MA): 2 (1%), probable migraine (PM): 4 (2%), tension-type headache (TTH): 39 (19.6%), cluster headache (CH): 2 (1%), posttraumatic headaches (PH): 2 (1%). 1-year prevalence of headaches in controls was 32.5% (63 patients out of 194), they included: TTH: 45 (23.1%), MO: 17(8.8%), PH: 1(0.5%). Only the prevalence of MO was significantly higher in patients with SIA (OR 6.7, 95% CI 3.8-11.9, p?



Great Earthquake Ruptures in the Age of Seismo-Geodesy  

NASA Astrophysics Data System (ADS)

During the past 10.5 years, twelve great (Mw ? 8.0) earthquake ruptures have struck near subduction zones around the Pacific rim, compared to nine great shallow events over the preceding 24 years. With the recent activity including 5 events larger than Mw 8.4, for which one must go back to the 1965 Rat Island earthquake to find a predecessor of comparable size, the recent activity level has been noted by seismologists and the public alike. During the relative lull in great earthquake activity during the 1980s and 1990s, seismologists and geodesists undertook major initiatives to deploy ground motion recording instruments around the world, exploiting developments in broadband seismology, GPS and InSAR. In parallel, improved technologies for recording well-calibrated tsunami observations were developed for deep ocean buoys and coastal installations. Important studies were conducted for the moderate size earthquakes recorded prior to the onset of the new millennium, with increasingly sophisticated finite-faulting inversion procedures exploiting the expanding ground and ocean motion data sets. This maturation of seismological and geodetic capabilities proved timely indeed, as unprecedented quantification of all of the recent great earthquakes has been achieved. Kinematic inversions for co-seismic rupture expansion and slip heterogeneity now exploit teleseismic and regional body waves and surface waves, campaign and high-rate GPS ground motion records, densely sampled ground motions from InSAR, and regional and remote tsunami recordings. Increasingly, joint inversions of diverse geophysical data sets are pursued, and distinctions between disciplines are blurring, as the complete ground motion history is analyzed by current seismo-geodesy approaches. This is exemplified by inversions of high-rate GPS recordings which explicitly include both time varying 'seismic' motions and static 'geodetic' offsets. Key insights into earthquake rupture processes stemming from the quantification of recent great events around the world will be discussed, highlighting the role of the complete ground motion analysis that is blending disciplinary approaches in a fashion that I am sure Beno Gutenberg would have found satisfying.

Lay, T.



Rupture of single receptor-ligand bonds: A new insight into probability distribution functions  

PubMed Central

Single molecule force spectroscopy is widely used to determine kinetic parameters of dissociation by analyzing bond rupture data obtained via applying mechanical force to cells, capsules, and beads that are attached to an intermolecular bond. The current analysis assumes that the intermolecular bond force is equal to the externally applied mechanical force. We confirm that viscous drag alone or in combination with cellular deformation resulting in viscoelasticity modulates bond force so that the instantaneous intermolecular bond force is not equivalent to the applied force. The bond force modulation leads to bond rupture time and force histograms that differ from those predicted by probability distribution functions (PDFs) using the current approach. A new methodology that accounts for bond force modulation in obtaining PDFs is presented. The predicted histograms from the new methodology are in excellent agreement with the respective histograms obtained from Monte Carlo simulation. PMID:23010061

Gupta, V.K.



The Modulus of Rupture from a Mathematical Point of View  

NASA Astrophysics Data System (ADS)

The goal of this work is to present a complete mathematical study about the three-point bending experiments and the modulus of rupture of brittle materials. We will present the mathematical model associated to three-point bending experiments and we will use the asymptotic expansion method to obtain a new formula to calculate the modulus of rupture. We will compare the modulus of rupture of porcelain obtained with the previous formula with that obtained by using the classic theoretical formula. Finally, we will also present one and three-dimensional numerical simulations to compute the modulus of rupture.

Quintela, P.; Sánchez, M. T.



What Is an Earthquake?: Fault-Rupture Analogies  

NSDL National Science Digital Library

This activity has two parts: the first part will demonstrate the weaknesses of simple fault models (like block diagrams) in depicting the process of fault rupture accurately; and the second part is centered around a fairly simple animation of rupture propagation, seen by an oblique map view, that attempts to show more accurately what we should envision when we think about fault rupture. This activity provides different analogies for describing the process of fault rupture, with attention paid to the strengths and weaknesses of each.


Ruptured abdominal aortic aneurysm presenting as buttock pain.  


This is the first case report of a ruptured aortic aneurysm presenting with acute right buttock pain. The patient was an 80 year old man. A literature search revealed one report of ruptured internal iliac artery aneurysm presenting with acute hip pain and another of an unruptured aortic aneurysm presenting with chronic hip pain. Thus the present case is another unusual presentation of ruptured abdominal aortic aneurysm and highlights the importance of careful history taking and clinical examination. A high index of clinical suspicion of aneurysm rupture should be maintained in elderly patients presenting with a history of collapse. PMID:15911962

Mahmood, F; Ahsan, F; Hockey, M



The relationship between plaque pH, plaque acid anion profiles, and oral carbohydrate retention after ingestion of several 'reference foods' by human subjects.  


The primary aim of this study was to rank several reference foods (apple drink, caramel, chocolate, cookie, skimmed milk powder, snack cracker, and wheat flake) according to their plaque pH response as monitored in a panel of 12 volunteers by the plaque-sampling method for comparison with data previously reported with other methods used to assess cariogenicity potential. Secondary experiments (using subsets of the panel of subjects) were undertaken in an attempt to elucidate some of the reasons for the observed plaque pH changes. Oral carbohydrate retention was measured at a single time period after food use as total anthrone-positive carbohydrate material, and as specific acidogenic sugars by gas-liquid chromatography after gel-exclusion chromatography. The concentrations of acid anions in the plaque fluid after food consumption were measured by isotachophoresis eight min after food use. According to the plaque pH response, apple-flavored fruit drink and chocolate were the most acidogenic foods and skimmed milk powder the least acidogenic. There were significant correlations (p less than 0.05) between the plaque pH data and lactate-plus-acetate concentrations in plaque fluid, but the correlations between the pH data and any of the carbohydrate retention parameters were not significant. PMID:3163354

Dodds, M W; Edgar, W M



Staining and calculus formation after 0.12% chlorhexidine rinses in plaque-free and plaque covered surfaces: a randomized trial  

PubMed Central

Objectives Studies concerning side effects of chlorhexidine as related to the presence of plaque are scarce. The purpose of this study was to compare the side effects of 0.12% chlorhexidine gluconate (CHX) on previously plaque-free (control group) and plaque-covered surfaces (test group). Methods This study had a single-blind, randomized, split-mouth, 21 days-experimental gingivitis design, including 20 individuals who abandoned all mechanical plaque control methods during 25 days. After 4 days of plaque accumulation, the individuals had 2 randomized quadrants cleaned, remaining 2 quadrants with plaque-covered dental surfaces. On the fourth day, the individuals started with 0.12% CHX rinsing lasting for 21 days. Stain index intensity and extent as well as calculus formation were evaluated during the experimental period. Results Intergroup comparisons showed statistically higher (p<0.05) stain intensity and extent index as well as calculus formation over the study in test surfaces as compared to control surfaces. Thus, 26.19% of test surfaces presented calculus, whereas calculus was observed in 4.52% in control surfaces. Conclusion The presence of plaque increased 0.12% CHX side effects. These results strengthen the necessity of biofilm disruption prior to the start of CHX mouthrinses in order to reduce side effects. PMID:21085810

ZANATTA, Fabrício Batistin; ANTONIAZZI, Raquel Pippi; RÖSING, Cassiano Kuchenbecker



Rapid control in ruptured abdominal aneurysms.  


Rapid control of a ruptured abdominal aneurysm can be achieved under local anesthesia by passing a Fogarty catheter, 8/22 F, retrograde from either femoral artery up into the thoracic aorta and inflating the balloon after administering heparin to the patient. This method avoids the often fatal hypotension that may occur with induction of general anesthesia in the hypovolemic patient. In cases in which the Fogarty catheter cannot pass up the iliac artery, direct insertion of the catheter through the aneurysm can be used, but this method requires the induction of general anesthesia prior to aortic control. PMID:7259508

Sensenig, D M



Quantitative assessment of carotid plaque surface irregularities and correlation to cerebrovascular symptoms  

PubMed Central

Background The purpose of this study was to determine whether surface irregularities measured from ultrasound images of carotid artery plaques and quantified using a novel method, correlate with the presence of ipsilateral hemispheric cerebrovascular symptoms. Methods A plaque surface irregularity index (SII) was measured in 47 carotid artery plaques (32 subjects, stenosis range 10% -95%, 49% symptomatic) using ultrasound image sequences spanning several cardiac cycles. The differences in the distribution of SII in plaques with ipsilateral hemispheric symptoms versus those without symptoms and the correlation between the SII of plaques and the degrees of stenosis of the corresponding arteries were assessed. Diagnostic performance of plaque SII was evaluated on its own and in combination with the degree of stenosis. Results The mean SII was significantly greater for plaques with ipsilateral hemispheric symptoms (1.89 radians/mm) than for asymptomatic plaques (1.67 radians/mm, p?=?0.03). There was no statistically significant association between the SII and the degree of stenosis (p?=?0.30). SII predicted the presence of cerebrovascular symptoms with an accuracy of 66% (sensitivity 65%, specificity 67%) on its own and with an accuracy of 83% (sensitivity 96%, specificity 71%) in combination with the degree of stenosis. Conclusions Quantitative assessment of carotid plaque surface irregularities using a novel SII parameter correlates with the presence ipsilateral hemispheric cerebrovascular symptoms and may increase diagnostic performance beyond that provided by the degree of stenosis. PMID:24195596



Dental plaque as a biofilm and new research on biofilm removal by power toothbrushes.  


Dental researchers have only recently begun to regard dental plaque as a biofilm. Dental plaque biofilm is a complex, heterogeneous structure of bacteria cells, a sticky extracellular matrix, and fluid channels. The biofilm must be modeled accurately for laboratory studies to be meaningful. To that end, researchers have compared the sonicare toothbrush to the Braun Oral-B 3D Excel Plaque Remover for the removal of interproximal dental plaque biofilm in an in vitro model. This article defines the concept of biofilms in the oral cavity and reviews how biofilm modeling is showing differences in toothbrush performance. PMID:12789977

Dudgeon, Douglas J; Berg, Joel



Plaque assay and cloning of scrub typhus rickettsiae in irradiated L-929 cells.  

PubMed Central

It was demonstrated that gamma-irradiated L-929 cells support plaque formation by three strains of Rickettsia tsutsugamushi and representative species of the spotted fever and typhus group rickettsiae. Sensitivity of the plaque assay for detection of viable scrub typhus rickettsiae was similar to that achieved with intraperitoneal inoculation of random-bred mice. The concentration of irradiated cells and the temperature and length of incubation were all found to affect plaque size. A technique combining terminal dilution and plaque purification was used to obtain clones of three strains of scrub typhus rickettsiae. Images PMID:69632

Oaks, S C; Osterman, J V; Hetrick, F M



[Near-infrared spectroscopy (NIRS), new intracoronary imaging technique of unstable coronary plaque].  


Acute coronary syndrome may develop in the background of hemodynamically non-significant coronary artery disease. It may be caused by the presence of "vulnerable plaque", which is characterized by the lipid rich core and thin fibrous cap content. NIRS - near infrared spectroscopy - is a morphological imaging method allowing determining atherosclerotic plaque cholesterol burden. Information about the chemical composition may contribute to "high risk" plaque early identification and subsequent optimal interventional strategy. The first experience with the clinical implementation of this novel method is demonstrated in a case report. Key words: acute coronary syndrome - chemogram - intravascular imaging - NIRS - vulnerable plaque. PMID:24974760

Ondrúš, Tomáš; Ka?ovský, Jan; Poloczek, Martin; Miklík, Roman; Bo?ek, Otakar; Je?ábek, Petr; Kala, Petr



Sphenoid Wing Meningioma en Plaque: A Clinical Review  

Microsoft Academic Search

Summary.\\u000a Summary.  \\u000a \\u000a \\u000a Objective.   To review the role of craniofacial resection and reconstruction in the treatment of patients with sphenoid wing meningioma\\u000a en plaque.\\u000a \\u000a \\u000a \\u000a Design:   15 patients were reviewed. The presenting features, operative details and complications were documented. The adequacy of\\u000a resection was reviewed and postoperative scans were analyzed to assess orbital reconstruction. Patients were assessed regarding\\u000a aesthetics and craniofacial function.

S. Honeybul; G. Neil-Dwyer; D. A. Lang; B. T. Evans; D. W. Ellison



A classic collaboration: Michael Davies on plaque vulnerability.  


The British Heart Foundation sponsors the Michael Davies Young Investigator Award, and at its presentation in the Spring of 2009 two collaborators of Michael Davies spoke regarding their experiences on the Plaque Vulnerability project with him. This was to provide the winner and other nominees for the award, and colleagues at the meeting, descriptions of collaborating with Michael to sustain more than his name in association with the award. This article is an expansion of the personal reminiscences given at the time as a tribute to him, and to provide an inside story of how collaboration with such a prominent cardiac pathologist worked. PMID:22196149

Born, G V R; Richardson, P D



Predicting Cesarean Section and Uterine Rupture among Women Attempting Vaginal Birth after Prior Cesarean Section  

Microsoft Academic Search

BackgroundThere is currently no validated method for antepartum prediction of the risk of failed vaginal birth after cesarean section and no information on the relationship between the risk of emergency cesarean delivery and the risk of uterine rupture.Methods and FindingsWe linked a national maternity hospital discharge database and a national registry of perinatal deaths. We studied 23,286 women with one

Gordon C. S. Smith; Ian R. White; Jill P. Pell; Richard Dobbie



Solitary plaque on the scalp as a primary manifestation of Hodgkin lymphoma: a case report and review of the literature.  


Cutaneous Hodgkin lymphoma is infrequent and typically occurs after extensive involvement of the lymph nodes. The condition decreased significantly in incidence in the past two decades, likely owing to the new treatment protocols composed of chemotherapy, radiotherapy and stem cell transplantation. Nevertheless, recognition of this uncommon but significant disease manifestation is important from a prognostic and therapeutic perspective. We are sharing a recent case of Hodgkin lymphoma where the primary presentation appeared as a solitary plaque on the left side of the occipital scalp, clinically suspected to represent a ruptured follicular cyst. The patient underwent excisional biopsy. Histological assessment revealed Hodgkin lymphoma affecting the skin. Radiological studies showed no regional lymphadenopathy. However, two enlarged lymph nodes were identified in the mediastinum and were positron emission tomography avid. The patient underwent systemic treatment without further histopathological examination of these two lymph nodes. Not being clear if these enlarged two lymph nodes were related to his cutaneous disease or not, we cannot be sure if the patient was afflicted either by primary cutaneous Hodgkin lymphoma or by secondary cutaneous involvement because of hematogenous spread. In either case, primary or secondary cutaneous Hodgkin disease is an extreme rarity. The literature is critically reviewed. PMID:19775396

Khalifeh, Ibrahim; Hughey, Lauren C; Huang, Conway C; Reddy, Vishnu V B; Sellheyer, Klaus



GPU Acceleration of Support Operator Rupture Dynamics  

NASA Astrophysics Data System (ADS)

SORD (Support Operator Rupture Dynamics) is an open-source software based on a fourth-order finite-difference method which can simulate 3D elastic wave propagation and spontaneous rupture on hexahedral mesh. It can be used for many kinds of surface boundary conditions, including free surface. The original software is developed by Geoffrey Ely from USC and modified by us for acceleration on GPU with NVIDIA CUDA. Our motivation on accelerating SORD on GPU is inspired by new generation GPU’s superior ability on general purpose computing and NVIDIA CUDA’s user-friendly developing environment for academic users. After translating the code from Fortran 95 to CUDA and implementing the transformed CUDA SORD code on the NVIDIA Tesla C1060, we obtained a factor of 6 speedup as compared to the original Fortran 95 version code , which was run on Intel Xeon X5570 2.9GHz. Our 3D wave solutions show explicitly visually in 3D format the different propagating wave fronts associated with the P and S waves according to the appropriate elastic parameter ratios. Because of the limitation of the global memory of NVIDIA Tesla C1060, too many more grid points would slow the calculation. However, by using the new NVIDIA Tesla C2070, which has 6 GBytes global memory, we can increase the simulation data size into 350X350X350.

Zhou, Y.; Dong, T.; Yuen, D. A.



[Spontaneous rupture of the spleen disclosing pheochromocytoma].  


The authors report a case of spontaneous rupture of spleen inaugurating the symptomatology of a pheochromocytoma. After presenting the observation, clinical problems are considered with a deceptive abdominal symptomatology and myocardial ischemia that could be part of an "adrenergic myocarditis"; the mechanism of ruptured spleen is analyzed. The diagnosis approach is discussed through a reliability study of various explorations: computed tomography has a sensitivity ranging from 93 to 97% which approaches 100% when associated with magnetic resonance, methyl-iodo-benzyl-guanidine scanning seems to be provided with similar reliability. During checking up for pheochromocytoma spreading, ectopic location was not found, but a cold thyroid nodule was detected which allowed suspecting a SIPPLE syndrome. The three-stage surgical approach was required by symptomatology, hemostasis splenectomy, lateral pheochromocytoma excision after a short preparation by blocking alpha and beta, and then total thyroidectomy after extemporaneous confirmation of the existence of a medullary carcinoma of the thyroid. This pathologic association leading to a SIPPLE syndrome is listed as part of the multiple endocrine neoplasias of type II (MEN II). PMID:2262521

Carles, J; Guegan, H; Crozat, T; Janvier, G; Riant, T; Videau, J



[Traumatic rupture of the descending aorta].  


During a ten-year period 16 patients were seen with aortic rupture and false aneurysm secondary to blunt trauma. One patient underwent an acute operation, 4 patients had operative therapy elective delayed and 11 patients were operated on for chronic traumatic false aneurysm. Operative delay was done in case of simultaneous multisystem injury (e.g. shock caused by abdominal injuries, cerebral contusion or pulmonary contusion on the right side). The shunt bypass method of repair was used in the case of 3 patients, cardiopulmonary bypass in 6 cases and simple aortic cross-clamping in 6 patients. One operation was performed without aortic cross-clamping. Primary repair was achieved in three patient, in 3 more cases a patch was inserted and in 9 cases interposition Dacron grafting was accomplished. One "wrapping" operation was performed. In 2 cases, reoperation was necessary because of postoperative bleeding. One patient died in the perioperative period. Right sided hemiparesis occurred in one patient postoperatively. Rupture does not affect the whole aortic wall, especially in young people because of the natural elasticity of vessel. The appearing shock and hypotension might protect the mediastinal pleura against bursting. This could provide a chance to survive. Our experience indicate: Elective delay of operation in patients with multiple system injuries can be achieved with antihypertensive therapy. PMID:9380385

Kovács, E; Dzsinich, C; Gyöngy, T; Moravcsik, E; Szabolcs, Z; Bodor, E



[Surgical consideration of ruptured abdominal aortic aneurysms].  


During the recent 18 and a half years, 30 cases of ruptured abdominal aortic aneurysm (including four cases of A-V fistula) were operated at Saiseikai Utsunomiya Hospital. In 26 cases, a conventional graft replacement was performed. In other four cases, axillo-bifemoral bypass (in the cases ruptured into the colon) or other methods were used. Overall operative mortality rate was 26.7%. However, during the last 9 years, operative results were improved (21.7%, 5 deaths out of 23 cases). Amount of intraoperative blood loss influenced the operative results greatly. Other operative risk factors included preoperative shock, preoperative severe cerebrovascular or cardiovascular complications, and postoperative thromboembolism. Factors of recent improvement in mortality included; establishment of emergency system which resulted in earlier operation after the patient's arrival at the hospital, use of occlusive balloon for bleeding control, heparin administration before the aortic clamp for preventing peripheral thromboembolism and introduction of autotransfusion system for reducing the amount of blood transfusion. PMID:2770687

Kiso, I; Yozu, R; Maehara, T; Umezu, Y; Hirotani, T; Ishikura, Y; Takeuchi, S



Management of extensor mechanism rupture after TKA.  


Disruption of the extensor mechanism in total knee arthroplasty may occur by tubercle avulsion, patellar or quadriceps tendon rupture, or patella fracture, and whether occurring intra-operatively or post-operatively can be difficult to manage and is associated with a significant rate of failure and associated complications. This surgery is frequently performed in compromised tissues, and repairs must frequently be protected with cerclage wiring and/or augmentation with local tendon (semi-tendinosis, gracilis) which may also be used to treat soft-tissue loss in the face of chronic disruption. Quadriceps rupture may be treated with conservative therapy if the patient retains active extension. Component loosening or loss of active extension of 20° or greater are clear indications for surgical treatment of patellar fracture. Acute patellar tendon disruption may be treated by primary repair. Chronic extensor failure is often complicated by tissue loss and retraction can be treated with medial gastrocnemius flaps, achilles tendon allografts, and complete extensor mechanism allografts. Attention to fixing the graft in full extension is mandatory to prevent severe extensor lag as the graft stretches out over time. PMID:23118397

Rosenberg, A G



Poxvirus membrane biogenesis: rupture not disruption  

PubMed Central

Summary Enveloped viruses acquire their membrane from the host by budding at, or wrapping by, cellular membranes. Transmission electron microscopy (TEM) images, however, suggested that the prototype member of the poxviridae, vaccinia virus (VACV), may create its membrane ‘de novo’ with free open ends exposed in the cytosol. Within the frame of the German-wide priority programme we re-addressed the biogenesis and origin of the VACV membrane using electron tomography (ET), cryo-EM and lipid analysis of purified VACV using mass spectrometry (MS). This review discussed how our data led to a model of unconventional membrane biogenesis involving membrane rupture and the generation of a single open membrane from open membrane intermediates. Lipid analyses of purified virus by MS suggest an ER origin with a relatively low cholesterol content compared with whole cells, confirming published data. Unlike previous reports using thin-layer chromatography, no depletion of phosphatidylethanolamine was detected. We did detect, however, an enrichment for phosphatidic acid, diacylglycerol and phosphatidylinositol in the virion. Our data are discussed in the light of other pathogens that may require cellular membrane rupture during their intracellular life cycle. PMID:23168015

Locker, Jacomine Krijnse; Chlanda, Petr; Sachsenheimer, Timo; Brugger, Britta



TMI-2 lower head creep rupture analysis  

SciTech Connect

The TMI-2 accident resulted in approximately 40% of the reactor's core melting and collecting on the lower head of the reactor pressure vessel. The severity of the accident has raised questions about the margin of safety against rupture of the lower head in this accident since all evidence seems to indicate no major breach of the vessel occurred. Scoping heat transfer analyses of the relocated core debris and lower head have been made based upon assumed core melting scenarios and core material debris formations while in contact with the lower head. This report describes the structural finite element creep rupture analysis of the lower head using a temperature transient judged most likely to challenge the structural capacity of the vessel. This evaluation of vessel response to this transient has provided insight into the creep mechanisms of the vessel wall, a realistic mode of failure, and a means by which margin to failure can be evaluated once examination provides estimated maximum wall temperatures. Suggestions for more extensive research in this area are also provided. 6 refs., 15 figs.

Thinnes, G.L.



Rupture velocity inferred from near-field differential ground motion  

NASA Astrophysics Data System (ADS)

The velocity of the rupture propagation is a fundamental source parameter that strongly affects ground motion. It is commonly assessed from kinematic inversion of strong-motion or teleseismic data, sometimes combined with InSar and/or GPS data. The obtained rupture velocity remains inevitably affected by uncertainties, mainly due to imperfect knowledge of the earth structure and tradeoffs between different source parameters. In this study we show how the analysis of differential ground-motion may help constraining the rupture velocity, without a priori information about the earth velocity structure. Our analysis is based on synthetic ground-motion simulations (0-2 Hz) for vertical strike-slip earthquakes propagating unilaterally at a fixed rupture velocity in a homogeneous elastic medium covered with a 1 km-thick low velocity layer (shear wave velocity equal to 1 km/s). We show that when the rupture reaches the bottom of the shallow layer, the phase velocity of transverse waves measured in the forward rupture direction up to a few rupture lengths is equal to the rupture velocity, for a large range of frequencies. The comparison with the phase velocity obtained for a point source then enables to retrieve the value of the rupture velocity. The phase velocity is simply computed from the ratio between the ground velocity and the shear strain or the rotation about a vertical axis. This study points out the utility of setting up dense arrays at the vicinity of major faults to retrieve rupture features such as the rupture velocity.

Causse, Mathieu; Cornou, Cécile; Bécasse, Julie; Bouchon, Michel



Acute tibialis posterior tendon rupture associated with a distal tibial fracture.  


Tibialis posterior tendon ruptures associated with closed medial malleolar fractures are rare. This article describes the association of tibialis posterior tendon ruptures with closed, high-energy, distal tibia fractures. Tendon ruptures are likely to be identified intraoperatively or missed if clinical evaluation at acute injury is limited. A high index of suspicion is required to diagnose this injury. The consequences of an unrecognized tibialis posterior tendon rupture include progressive, painful pes planus deformities due to the unopposed action of the peroneus brevis muscle and lack of support of the medial longitudinal arch. Secondary operative intervention may be required. This article describes an intraoperative tenodesis technique between the tibialis posterior and flexor digitorum longus tendons when direct repair is not possible.A 48-year-old woman sustained a closed AO/Orthopaedic Trauma Association type 43A right lower-extremity distal tibia fracture and a traumatic left knee arthrotomy. Temporary stabilization with an external fixator was performed, followed by open reduction and internal fixation of the distal tibial fracture 6 days later. A periarticular nonlocking medial plate was applied, and the tibialis posterior tendon was shortened. We performed a direct tenodesis to the flexor digitorum longus tendon. At 1-year follow-up, the patient had made excellent progress, with no detectable muscle weakness, and was able to perform a single-leg toe raise.A review of the literature suggested which features of radiological evidence of tendon rupture should be examined, which may be useful in the current era considering most high-energy distal tibia or pilon fractures undergo examination with computed tomography. PMID:22495868

Jarvis, Hannah C; Cannada, Lisa K



Performance of digital RGB reflectance color extraction for plaque lesion  

NASA Astrophysics Data System (ADS)

Several clinical psoriasis lesion groups are been studied for digital RGB color features extraction. Previous works have used samples size that included all the outliers lying beyond the standard deviation factors from the peak histograms. This paper described the statistical performances of the RGB model with and without removing these outliers. Plaque lesion is experimented with other types of psoriasis. The statistical tests are compared with respect to three samples size; the original 90 samples, the first size reduction by removing outliers from 2 standard deviation distances (2SD) and the second size reduction by removing outliers from 1 standard deviation distance (1SD). Quantification of data images through the normal/direct and differential of the conventional reflectance method is considered. Results performances are concluded by observing the error plots with 95% confidence interval and findings of the inference T-tests applied. The statistical tests outcomes have shown that B component for conventional differential method can be used to distinctively classify plaque from the other psoriasis groups in consistent with the error plots finding with an improvement in p-value greater than 0.5.

Hashim, Hadzli; Taib, Mohd Nasir; Jailani, Rozita; Sulaiman, Saadiah; Baba, Roshidah



Evidence-based control of plaque and gingivitis.  


Most adults brush and floss inadequately, and constant education and/or reinforcement is often required. Bacteria are usually left behind with mechanical oral health routines, and chemotherapeutic agents may have a key role as adjuncts to daily home-care. To date, two antiseptic mouthwashes have received the ADA Seal of Acceptance: Peridex (Zila Pharmaceuticals, Phoenix, AZ, USA; CHX, chlorhexidine) and Listerine (Pfizer Consumer Healthcare, Morris Plains, NJ, USA; essential oil (EO) mouthwash). CHX has a strong affinity for tooth and tissue surfaces, but can cause brown staining on the teeth and tongue. Patients must also wait until all traces of toothpaste are removed before rinsing with CHX. Long-term use of an EO mouthwash is microbiologically safe, with no changes observed in the bacterial composition of supragingival plaque, and no evidence of antimicrobial resistance. A number of trials have demonstrated the long-term plaque- and gingivitis-reducing properties of both CHX and EO mouthwashes. These studies clearly demonstrate that these agents have lasting efficacy, and can access hard-to-reach areas. PMID:12787197

Santos, A



Modified COMS Plaques for {sup 125}I and {sup 103}Pd Iris Melanoma Brachytherapy  

SciTech Connect

Purpose: Novel plaques are used to treat iris melanoma at the Mayo Clinic Rochester. The plaques are a modification of the Collaborative Ocular Melanoma Study (COMS) 22 mm plaque design with a gold alloy backing, outer lip, and silicone polymer insert. An inner lip surrounds a 10 mm diameter cutout region at the plaque center. Plaques span 360{sup o}, 270{sup o}, and 180{sup o} arcs. This article describes dosimetry for these plaques and others used in the treatment of anterior eye melanomas. Methods and Materials: The EGSnrc user-code BrachyDose is used to perform Monte Carlo simulations. Plaques and seeds are fully modeled. Three-dimensional dose distributions for different plaque models, TG-43 calculations, and {sup 125}I (model 6711) and {sup 103}Pd (model 200) seeds are compared via depth-dose curves, tabulation of doses at points of interest, and isodose contours. Results: Doses at points of interest differ by up to 70% from TG-43 calculations. The inner lip reduces corneal doses. Matching plaque arc length to tumor extent reduces doses to eye regions outside the treatment area. Maintaining the same prescription dose, {sup 103}Pd offers lower doses to critical structures than {sup 125}I, with the exception of the sclera adjacent to the plaque. Conclusion: The Mayo Clinic plaques offer several advantages for anterior eye tumor treatments. Doses to regions outside the treatment area are significantly reduced. Doses differ considerably from TG-43 predictions, illustrating the importance of complete Monte Carlo simulations. Calculations take a few minutes on a single CPU, making BrachyDose sufficiently fast for routine clinical treatment planning.

Thomson, Rowan M., E-mail: rthomson@physics.carleton.c [Ottawa Carleton Institute of Physics, Carleton University, Ottawa, ON (Canada); Furutani, Keith M.; Pulido, Jose S.; Stafford, Scott L. [Mayo Clinic College of Medicine, Rochester, MN (United States); Rogers, D.W.O. [Ottawa Carleton Institute of Physics, Carleton University, Ottawa, ON (Canada)



Nestin and WT1 expression in atheromathous plaque neovessels: Association with vulnerability.  


Introduction. Neoangiogenesis is crucial for the progression and vulnerability of atheromasic lesions. Since adult vasa vasorum, which represent the neoangiogenetic burden of healthy arteries, constitutively express Nestin and Wilms Tumor (WT1), the aims of the present study are: i) to describe and quantify Nestin and WT1 in plaque neovessels; ii) to investigate the relationship between neovessel phenotype and plaque instability. Methods. We prospectively evaluated 49 consecutive carotid endarterectomy specimens. Histopathological characteristics were separately collected, particularly the intraplaque histological complications. Immunohistochemistry was carried out for CD34, Nestin and WT1; the density of positivity was evaluated for each marker. RT-PCR was performed to assess Nestin and WT1 mRNA levels on the first 10 plaques and on 10 control arteries. Results. Six (12.2%) plaques showed no neoangiogenesis. In the others, the mean immunohistochemical densities of CD34, Nestin, and WT1-positive structures were 41.88, 28.84 and 17.68/mm2. Among the CD34+ neovessels, 68% and 42% expressed Nestin and WT1 respectively, i.e., nearly 36% of the neovessels resulted to be Nestin+/WT1-. Furthermore, complicated plaques (n=30) showed significantly more CD34 and Nestin-positive vessels than uncomplicated plaques (n=13; P=0.045 and P=0.009), while WT1 was not increased (P=0.139). RT-PCR confirmed that WT1 gene expression was 3-fold lower than Nestin gene in plaques (p=0.001). Conclusions. Plaque neoangiogenesis shows both a Nestin+/WT1- and a Nestin+/WT1+ phenotype. The Nestin+/WT1- neovessels are significantly more abundant in complicated (vulnerable) plaques. The identification of new transcription factors in plaque neoangiogenesis, and their possible regulation, can open new perspectives in the therapy of vulnerable plaques. PMID:24861148

Fittipaldi, Silvia; Vasuri, Francesco; Degiovanni, Alessio; Pini, Rodolfo; Mauro, Raffaella; Faggioli, Gianluca; D'Errico-Grigioni, Antonia; Stella, Andrea; Pasquinelli, Gianandrea



Membrane Currents in Identified Lactotrophs of Rat Anterior Pituitary  

Microsoft Academic Search

Qualitative features of the primary inward and outward current components of identified lactotrophs of the rat anterior pituitary were examined. Identification of lactotrophs in heterogeneous dissociated anterior pituitary cultures was accomplished by ap- plication of the reverse hemolytic plaque assay. Currents in lac- totrophs were subsequently examined using whole-cell or patch recording techniques. Two components of inward calcium current were

Christopher J. Lingle; Sompong Sombati; Marc E. Freeman