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Sample records for plaque rupture current

  1. Animal models for plaque rupture: a biomechanical assessment.

    PubMed

    van der Heiden, Kim; Hoogendoorn, Ayla; Daemen, Mat J; Gijsen, Frank J H

    2016-02-29

    Rupture of atherosclerotic plaques is the main cause of acute cardiovascular events. Animal models of plaque rupture are rare but essential for testing new imaging modalities to enable diagnosis of the patient at risk. Moreover, they enable the design of new treatment strategies to prevent plaque rupture. Several animal models for the study of atherosclerosis are available. Plaque rupture in these models only occurs following severe surgical or pharmaceutical intervention. In the process of plaque rupture, composition, biology and mechanics each play a role, but the latter has been disregarded in many animal studies. The biomechanical environment for atherosclerotic plaques is comprised of two parts, the pressure-induced stress distribution, mainly - but not exclusively - influenced by plaque composition, and the strength distribution throughout the plaque, largely determined by the inflammatory state. This environment differs considerably between humans and most animals, resulting in suboptimal conditions for plaque rupture. In this review we describe the role of the biomechanical environment in plaque rupture and assess this environment in animal models that present with plaque rupture. PMID:26607378

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

    PubMed Central

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

    2014-01-01

    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

  3. Matrix vesicles in the fibrous cap of atherosclerotic plaque: possible contribution to plaque rupture

    PubMed Central

    Bobryshev, Y V; Killingsworth, M C; Lord, R S A; Grabs, A J

    2008-01-01

    Plaque rupture is the most common type of plaque complication and leads to acute ischaemic events such as myocardial infarction and stroke. Calcification has been suggested as a possible indicator of plaque instability. Although the role of matrix vesicles in the initial stages of arterial calcification has been recognized, no studies have yet been carried out to examine a possible role of matrix vesicles in plaque destabilization. Tissue specimens selected for the present study represented carotid specimens obtained from patients undergoing carotid endarterectomy. Serial frozen cross-sections of the tissue specimens were cut and mounted on glass slides. The thickness of the fibrous cap (FCT) in each advanced atherosclerotic lesion, containing a well developed lipid/necrotic core, was measured at its narrowest sites in sets of serial sections. According to established criteria, atherosclerotic plaque specimens were histologically subdivided into two groups: vulnerable plaques with thin fibrous caps (FCT <100 ?m) and presumably stable plaques, in which fibrous caps were thicker than 100 ?m. Twenty-four carotid plaques (12 vulnerable and 12 presumably stable plaques) were collected for the present analysis of matrix vesicles in fibrous caps. In order to provide a sufficient number of representative areas from each plaque, laser capture microdissection (LCM) was carried out. The quantification of matrix vesicles in ultrathin sections of vulnerable and stable plaques revealed that the numbers of matrix vesicles were significantly higher in fibrous caps of vulnerable plaques than those in stable plaques (8.908±0.544 versus 6.208±0.467 matrix vesicles per 1.92 ?m2 standard area; P= 0.0002). Electron microscopy combined with X-ray elemental microanalysis showed that some matrix vesicles in atherosclerotic plaques were undergoing calcification and were characterized by a high content of calcium and phosphorus. The percentage of calcified matrix vesicles/microcalcifications was significantly higher in fibrous caps in vulnerable plaques compared with that in stable plaques (6.705±0.436 versus 5.322±0A94; P= 0.0474). The findings reinforce a view that the texture of the extracellular matrix in the thinning fibrous cap of atherosclerotic plaque is altered and this might contribute to plaque destabilization. PMID:18194456

  4. Changing Views of the Biomechanics of Vulnerable Plaque Rupture, a Review

    PubMed Central

    Cardoso, Luis; Weinbaum, Sheldon

    2013-01-01

    This review examines changing perspectives on the biomechanics of vulnerable plaque rupture over the past 25 years from the first 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 μm 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 locals regions of high stress concentration between closely spaced microinclusions oriented along their tensile axis. PMID:23842694

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

    PubMed

    Nadkarni, Seemantini K

    2013-12-01

    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

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

    PubMed Central

    2013-01-01

    Abstract. 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

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

    NASA Astrophysics Data System (ADS)

    Nadkarni, Seemantini K.

    2013-12-01

    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.

  8. Is Cadmium Exposure Associated with the Burden, Vulnerability and Rupture of Human Atherosclerotic Plaques?

    PubMed Central

    Sallsten, Gerd; Lundh, Thomas; Barregard, Lars

    2015-01-01

    The general population is exposed to cadmium from food and smoking. Cadmium is a widely spread toxic pollutant that seems to be associated with cardiovascular diseases, although little is known if it contributes to the occurrence of atherosclerotic plaques and the process whereby plaques become vulnerable and are prone to rupture. We tested the hypotheses that cadmium exposure is associated not only with an increased subclinical burden of atherosclerotic plaques in different vascular territories and early signs of plaque vulnerability, but also with cadmium content and plaque-rupture in the clinical phase of the disease. Ultrasound technique was used to measure plaque prevalence and echogenicity in the carotid and femoral arteries in a population sample of women (n = 599) in whom blood cadmium was measured. In addition cadmium was measured in snap-frozen endarterectomies and whole blood obtained from patients who were referred to surgery because of symptomatic carotid plaques (n = 37). Sixteen endarterectomies were divided into three parts corresponding to different flow conditions and plaque vulnerability. In the population sample blood cadmium was associated with the number of vascular territories with plaques (p = 0.003 after adjustment for potential confounders). The cadmium concentrations in symptomatic plaques were 50-fold higher in plaque tissue than in blood. Cadmium levels in blood and plaque correlated, also after adjustment for smoking and other cardiovascular risk factors (p<0.001). Compared with the other parts of the plaque, the cadmium content was double as high in the part where plaque rupture usually occurs. In conclusion, the results show that cadmium exposure is associated with the burden of subclinical atherosclerosis in middle-aged women with different degrees of glucose tolerance, and that the content of cadmium in symptomatic plaques in patients is related to that in blood, but much higher, and preferentially located in the part of plaque where rupture often occurs. PMID:25816093

  9. Sonographic Detection of Abnormal Plaque Motion of the Carotid Artery: Its Usefulness in Diagnosing High-Risk Lesions Ranging from Plaque Rupture to Ulcer Formation.

    PubMed

    Muraki, Mutsuko; Mikami, Taisei; Yoshimoto, Tetsuyuki; Fujimoto, Shin; Kitaguchi, Mayumi; Kaga, Sanae; Sugawara, Tomoko; Tokuda, Kouichi; Kaneko, Sadao; Kashiwaba, Takeshi

    2016-02-01

    We investigated the feasibility of using sonography of abnormal plaque motion to diagnose high-risk carotid lesions ranging from plaque rupture to ulcer formation. Fifty consecutive carotid arteries of 49 patients (71 ± 7 y, 37 males) who underwent carotid endarterectomy were investigated by carotid sonography to find a plaque concavity (sonographic ulcer [SU]), fine trembling motion inside the plaque (FTMI) and systolic retractive motion of the plaque surface (SRMS). Plaque rupture or ulcer, necrotic core and intra-plaque hemorrhage were determined at carotid endarterectomy. Twenty-two SUs, 41 cases of FTMI and 20 cases of SRMS were detected by carotid sonography. The sensitivity and specificity of SU in diagnosing plaque rupture or ulcer at carotid endarterectomy were 48% and 90%, and those of FTMI were 93% and 60%. Plaques with SRMS more frequently had both a necrotic core and intra-plaque hemorrhage than those without SRMS (80% vs. 30%, p = 0.0005). Abnormal plaque motion detected by carotid sonography is useful in detecting a ruptured or ulcerated plaque with a necrotic core and/or hemorrhage. PMID:26589531

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

    PubMed Central

    2014-01-01

    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

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

    PubMed Central

    Bond, Andrew R.; Jackson, Christopher L.

    2011-01-01

    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

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

    PubMed Central

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

    2013-01-01

    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

  13. How do we prevent the vulnerable atherosclerotic plaque from rupturing? Insights from in vivo assessments of plaque, vascular remodeling, and local endothelial shear stress.

    PubMed

    Andreou, Ioannis; Antoniadis, Antonios P; Shishido, Koki; Papafaklis, Michail I; Koskinas, Konstantinos C; Chatzizisis, Yiannis S; Coskun, Ahmet U; Edelman, Elazer R; Feldman, Charles L; Stone, Peter H

    2015-05-01

    Coronary atherosclerosis progresses both as slow, gradual enlargement of focal plaque and also as a more dynamic process with periodic abrupt changes in plaque geometry, size, and morphology. Systemic vasculoprotective therapies such as statins, angiotensin-converting enzyme inhibitors, and antiplatelet agents are the cornerstone of prevention of plaque rupture and new adverse clinical outcomes, but such systemic therapies are insufficient to prevent the majority of new cardiac events. Invasive imaging methods have been able to identify both the anatomic features of high-risk plaque and the ongoing pathobiological stimuli responsible for progressive plaque inflammation and instability and may provide sufficient information to formulate preventive local mechanical strategies (eg, preemptive percutaneous coronary interventions) to avert cardiac events. Local endothelial shear stress (ESS) triggers vascular phenomena that synergistically exacerbate atherosclerosis toward an unstable phenotype. Specifically, low ESS augments lipid uptake and catabolism, induces plaque inflammation and oxidation, downregulates the production, upregulates the degradation of extracellular matrix, and increases cellular apoptosis ultimately leading to thin-cap fibroatheromas and/or endothelial erosions. Increases in blood thrombogenicity that result from either high or low ESS also contribute to plaque destabilization. An understanding of the actively evolving vascular phenomena, as well as the development of in vivo imaging methodologies to identify the presence and severity of the different processes, may enable early identification of a coronary plaque destined to acquire a high-risk state and allow for highly selective, focal preventive interventions to avert the adverse natural history of that particular plaque. In this review, we focus on the role of ESS in the pathobiologic processes responsible for plaque destabilization, leading either to accelerated plaque growth or to acute coronary events, and emphasize the potential to utilize in vivo risk stratification of individual coronary plaques to optimize prevention strategies to preclude new cardiac events. PMID:25336461

  14. Necrotic core thickness and positive arterial remodeling index: emergent biomechanical factors for evaluating the risk of plaque rupture

    PubMed Central

    Ohayon, Jacques; Finet, Gérard; Gharib, Ahmed M.; Herzka, Daniel A.; Tracqui, Philippe; Heroux, Julie; Rioufol, Gilles; Kotys, Melanie S.; Elagha, Abdalla; Pettigrew, Roderic I.

    2008-01-01

    Fibrous cap thickness is often considered as diagnostic of the degree of plaque instability. Necrotic core area (Corearea) and the arterial remodeling index (Remodindex), on the other hand, are difficult to use as clinical morphological indexes: literature data show a wide dispersion of Corearea thresholds above which plaque becomes unstable. Although histopathology shows a strong correlation between Corearea and Remodindex, it remains unclear how these interact and affect peak cap stress (Capstress), a known predictor of rupture. The aim of this study was to investigate the change in plaque vulnerability as a function of necrotic core size and plaque morphology. Capstress value was calculated on 5,500 idealized atherosclerotic vessel models that had the original feature of mimicking the positive arterial remodeling process described by Glagov. Twenty-four nonruptured plaques acquired by intravascular ultrasound on patients were used to test the performance of the associated idealized morphological models. Taking advantage of the extensive simulations, we investigated the effects of anatomical plaque features on Capstress. It was found that: 1) at the early stages of positive remodeling, lesions were more prone to rupture, which could explain the progression and growth of clinically silent plaques and 2) in addition to cap thickness, necrotic core thickness, rather than area, was critical in determining plaque stability. This study demonstrates that plaque instability is to be viewed not as a consequence of fibrous cap thickness alone but rather as a combination of cap thickness, necrotic core thickness, and the arterial remodeling index. PMID:18586893

  15. Bacteria Present in Carotid Arterial Plaques Are Found as Biofilm Deposits Which May Contribute to Enhanced Risk of Plaque Rupture

    PubMed Central

    Lanter, Bernard B.; Sauer, Karin

    2014-01-01

    ABSTRACT Atherosclerosis, a disease condition resulting from the buildup of fatty plaque deposits within arterial walls, is the major underlying cause of ischemia (restriction of the blood), leading to obstruction of peripheral arteries, congestive heart failure, heart attack, and stroke in humans. Emerging research indicates that factors including inflammation and infection may play a key role in the progression of atherosclerosis. In the current work, atherosclerotic carotid artery explants from 15 patients were all shown to test positive for the presence of eubacterial 16S rRNA genes. Density gradient gel electrophoresis of 5 of these samples revealed that each contained 10 or more distinct 16S rRNA gene sequences. Direct microscopic observation of transverse sections from 5 diseased carotid arteries analyzed with a eubacterium-specific peptide nucleic acid probe revealed these to have formed biofilm deposits, with from 1 to 6 deposits per thin section of plaque analyzed. A majority, 93%, of deposits was located proximal to the internal elastic lamina and associated with fibrous tissue. In 6 of the 15 plaques analyzed, 16S rRNA genes from Pseudomonas spp. were detected. Pseudomonas aeruginosa biofilms have been shown in our lab to undergo a dispersion response when challenged with free iron in vitro. Iron is known to be released into the blood by transferrin following interaction with catecholamine hormones, such as norepinephrine. Experiments performed in vitro showed that addition of physiologically relevant levels of norepinephrine induced dispersion of P. aeruginosa biofilms when grown under low iron conditions in the presence but not in the absence of physiological levels of transferrin. PMID:24917599

  16. Very late neoatherosclerotic plaque rupture in drug-eluting stent restenosis.

    PubMed

    Courand, Pierre-Yves; Dementhon, Julie; Rioufol, Gilles; Finet, Gérard

    2015-01-01

    A 71-year-old man presented in emergency department for non-ST-elevation myocardial infarction. At admission, 12-lead ECG was in sinus rhythm without sign of myocardial ischemia, and troponin slightly increased. The only notable feature of the patient's medical history was single-vessel coronary artery disease revealed 10 years previously, treated by stenting of the second segment of the right coronary artery with a 3.0 x 25?mm bare metal stent. Three months later, intrastent restenosis was managed by implantation of a 3.0?×?28?mm paclitaxel-eluting stent. Two years before the present admission, following a non contributive stress test for atypical chest pain, coronary angiogram had found a 60% diffuse intrastent restenosis. The present coronary angiogram performed via a right transradial approach demonstrated a focal intrastent restenosis (85%) with irregular contours. Optical coherence tomography (OCT) showed an atherosclerotic intrastent neolesion with intimal tear. OCT demonstrated more precisely a minimal luminal area of 1.02?mm (77.9% area stenosis), two wide cavities (length 1.1 and 1.4?mm) separated by a plaque rupture of 6.8?mm. Myocardial ischemia was evenly demonstrated on this artery with a fractional flow reserve under 0.50 after 150?mg intracoronary adenosine bolus. The culprit lesion was treated by a 3.0?×?38?mm everolimus-eluting stent, with good angiographic results, confirmed on OCT. PMID:25333374

  17. Imaging the vulnerable plaque.

    PubMed

    Vancraeynest, David; Pasquet, Agnes; Roelants, Véronique; Gerber, Bernhard L; Vanoverschelde, Jean-Louis J

    2011-05-17

    Cardiovascular diseases are still the primary causes of mortality in the United States and in Western Europe. Arterial thrombosis is triggered by a ruptured atherosclerotic plaque and precipitates an acute vascular event, which is responsible for the high mortality rate. These rupture-prone plaques are called "vulnerable plaques." During the past decades, much effort has been put toward accurately detecting the presence of vulnerable plaques with different imaging techniques. In this review, we provide an overview of the currently available invasive and noninvasive imaging modalities used to detect vulnerable plaques. We will discuss the upcoming challenges in translating these techniques into clinical practice and in assigning them their exact place in the decision-making process. PMID:21565634

  18. Longitudinal necrotic shafts near TCFAs--a potential novel mechanism for plaque rupture to trigger ACS?

    PubMed

    Brezinski, Mark E; Harjai, Kishore J

    2014-12-20

    It has been questioned for over 15 years why only less than 20% of TCFAs trigger ACS. We illustrate TCFA rupture into adjacent longitudinal necrotic shafts of massive amounts of thrombogenic material into the blood, leading to catastrophic clot formation. This is the potential mechanism for TCFAs triggering ACS. One case presented also illustrates the dangers of stent edges rupturing TCFAs. PMID:25449500

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

    PubMed Central

    2014-01-01

    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

  20. Plaque Size Is Decreased but M1 Macrophage Polarization and Rupture Related Metalloproteinase Expression Are Maintained after Deleting T-Bet in ApoE Null Mice

    PubMed Central

    Tsaousi, Aikaterini; Hayes, Elaine M.; Di Gregoli, Karina; Bond, Andrew R.; Bevan, Laura

    2016-01-01

    Background Thelper1 (Th1) lymphocytes have been previously implicated in atherosclerotic plaque growth but their role in plaque vulnerability to rupture is less clear. We investigated whether T-bet knockout that prevents Th1 lymphocyte differentiation modulates classical (M1) macrophage activation or production of matrix degrading metalloproteinases (MMPs) and their tissue inhibitors, TIMPs. Methods & Results We studied the effect of T-bet deletion in apolipoproteinE (ApoE) knockout mice fed a high fat diet (HFD) or normal chow diet (ND). Transcript levels of M1/M2 macrophage polarization markers, selected MMPs and TIMPs were measured by RT-qPCR in macrophages isolated from subcutaneous granulomas or in whole aortae. Immunohistochemistry of aortic sinus (AS) and brachiocephalic artery (BCA) plaques was conducted to quantify protein expression of the same factors. Deletion of T-bet decreased mRNA for the M1 marker NOS-2 in granuloma macrophages but levels of M2 markers (CD206, arginase-1 and Ym-1), MMPs-2, -9, -12, -13, -14 and -19 or TIMPs-1 to -3 were unchanged. No mRNA differences were observed in aortic extracts from mice fed a HFD for 12 weeks. Moreover, AS and BCA plaques were similarly sized between genotypes, and had similar areas stained for NOS-2, COX-2, MMP-12 and MMP-14 proteins. T-bet deletion increased MMP-13, MMP-14 and arginase-1 in AS plaques. After 35 weeks of ND, T-bet deletion reduced the size of AS and BCA plaques but there were no differences in the percentage areas stained for M1 or M2 markers, MMPs-12, -13, -14, or TIMP-3. Conclusions Absence of Th1 lymphocytes is associated with reduced plaque size in ApoE knockout mice fed a normal but not high fat diet. In either case, M1 macrophage polarization and expression of several MMPs related to plaque instability are either maintained or increased. PMID:26886778

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

    PubMed Central

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

    2013-01-01

    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

  2. Imaging Modalities to Identity Inflammation in an Atherosclerotic Plaque

    PubMed Central

    Goel, Sunny; Miller, Avraham; Agarwal, Chirag; Zakin, Elina; Acholonu, Michael; Gidwani, Umesh; Sharma, Abhishek; Kulbak, Guy; Shani, Jacob; Chen, On

    2015-01-01

    Atherosclerosis is a chronic, progressive, multifocal arterial wall disease caused by local and systemic inflammation responsible for major cardiovascular complications such as myocardial infarction and stroke. With the recent understanding that vulnerable plaque erosion and rupture, with subsequent thrombosis, rather than luminal stenosis, is the underlying cause of acute ischemic events, there has been a shift of focus to understand the mechanisms that make an atherosclerotic plaque unstable or vulnerable to rupture. The presence of inflammation in the atherosclerotic plaque has been considered as one of the initial events which convert a stable plaque into an unstable and vulnerable plaque. This paper systemically reviews the noninvasive and invasive imaging modalities that are currently available to detect this inflammatory process, at least in the intermediate stages, and discusses the ongoing studies that will help us to better understand and identify it at the molecular level. PMID:26798515

  3. Current Management of Traumatic Rupture of the Descending Thoracic Aorta

    PubMed Central

    Karmy-Jones, Riyad; Jackson, Nichole; Long, William; Simeone, Alan

    2009-01-01

    Traumatic rupture of the descending thoracic aorta remains a leading cause of death following major blunt trauma. Management has evolved from uniformly performing emergent open repair with clamp and sew technique to include open repair with mechanical circulatory support, medical management and most recently, endovascular repair. This latter approach appears, in the short term, to be associated with perhaps better outcome, but long term data is still accruing. While an attractive option, there are specific anatomic and physiologic factors to be considered in each individual case. PMID:20676277

  4. Acute perioperative-stress-induced increase of atherosclerotic plaque volume and vulnerability to rupture in apolipoprotein-E-deficient mice is amenable to statin treatment and IL-6 inhibition.

    PubMed

    Janssen, Henrike; Wagner, Christian S; Demmer, Philipp; Callies, Simone; Sölter, Gesine; Loghmani-khouzani, Houra; Hu, Niandan; Schuett, Harald; Tietge, Uwe J F; Warnecke, Gregor; Larmann, Jan; Theilmeier, Gregor

    2015-09-01

    Myocardial infarction and stroke are frequent after surgical procedures and consume a considerable amount of benefit of surgical therapy. Perioperative stress, induced by surgery, is composed of hemodynamic and inflammatory reactions. The effects of perioperative stress on atherosclerotic plaques are ill-defined. Murine models to investigate the influence of perioperative stress on plaque stability and rupture are not available. We developed a model to investigate the influence of perioperative stress on plaque growth and stability by exposing apolipoprotein-E-deficient mice, fed a high cholesterol diet for 7?weeks, to a double hit consisting of 30?min of laparotomy combined with a substantial blood loss (approximately 20% of total blood volume; 400?µl). The innominate artery was harvested 72?h after the intervention. Control groups were sham and baseline controls. Interleukin-6 (IL-6) and serum amyloid A (SAA) plasma levels were determined. Plaque load, vascular smooth muscle cell (VSMC) and macrophage content were quantified. Plaque stability was assessed using the Stary score and frequency of signs of plaque rupture were assessed. High-dose atorvastatin (80?mg/kg body weight/day) was administered for 6?days starting 3?days prior to the double hit. A single dose of an IL-6-neutralizing antibody or the fusion protein gp130-Fc selectively targeting IL-6 trans-signaling was subcutaneously injected. IL-6 plasma levels increased, peaking at 6?h after the intervention. SAA levels peaked at 24?h (n=4, P<0.01). Plaque volume increased significantly with the double hit compared to sham (n=8, P<0.01). More plaques were scored as complex or bearing signs of rupture after the double hit compared to sham (n=5-8, P<0.05). Relative VSMC and macrophage content remained unchanged. IL-6-inhibition or atorvastatin, but not blocking of IL-6 trans-signaling, significantly decreased plaque volume and complexity (n=8, P<0.01). Using this model, researchers will be able to further investigate the pathophysiology of perioperative plaque stability, which can result in myocardial infarction, and, additionally, to test potential protective strategies. PMID:26092124

  5. Acute perioperative-stress-induced increase of atherosclerotic plaque volume and vulnerability to rupture in apolipoprotein-E-deficient mice is amenable to statin treatment and IL-6 inhibition

    PubMed Central

    Janssen, Henrike; Wagner, Christian S.; Demmer, Philipp; Callies, Simone; Sölter, Gesine; Loghmani-khouzani, Houra; Hu, Niandan; Schuett, Harald; Tietge, Uwe J. F.; Warnecke, Gregor; Larmann, Jan; Theilmeier, Gregor

    2015-01-01

    ABSTRACT Myocardial infarction and stroke are frequent after surgical procedures and consume a considerable amount of benefit of surgical therapy. Perioperative stress, induced by surgery, is composed of hemodynamic and inflammatory reactions. The effects of perioperative stress on atherosclerotic plaques are ill-defined. Murine models to investigate the influence of perioperative stress on plaque stability and rupture are not available. We developed a model to investigate the influence of perioperative stress on plaque growth and stability by exposing apolipoprotein-E-deficient mice, fed a high cholesterol diet for 7?weeks, to a double hit consisting of 30?min of laparotomy combined with a substantial blood loss (approximately 20% of total blood volume; 400?µl). The innominate artery was harvested 72?h after the intervention. Control groups were sham and baseline controls. Interleukin-6 (IL-6) and serum amyloid A (SAA) plasma levels were determined. Plaque load, vascular smooth muscle cell (VSMC) and macrophage content were quantified. Plaque stability was assessed using the Stary score and frequency of signs of plaque rupture were assessed. High-dose atorvastatin (80?mg/kg body weight/day) was administered for 6?days starting 3?days prior to the double hit. A single dose of an IL-6-neutralizing antibody or the fusion protein gp130-Fc selectively targeting IL-6 trans-signaling was subcutaneously injected. IL-6 plasma levels increased, peaking at 6?h after the intervention. SAA levels peaked at 24?h (n=4, P<0.01). Plaque volume increased significantly with the double hit compared to sham (n=8, P<0.01). More plaques were scored as complex or bearing signs of rupture after the double hit compared to sham (n=5-8, P<0.05). Relative VSMC and macrophage content remained unchanged. IL-6-inhibition or atorvastatin, but not blocking of IL-6 trans-signaling, significantly decreased plaque volume and complexity (n=8, P<0.01). Using this model, researchers will be able to further investigate the pathophysiology of perioperative plaque stability, which can result in myocardial infarction, and, additionally, to test potential protective strategies. PMID:26092124

  6. Detecting the vulnerable plaque in patients.

    PubMed

    Gonçalves, I; den Ruijter, H; Nahrendorf, M; Pasterkamp, G

    2015-11-01

    Atherosclerosis is a systemic condition that eventually evolves into vulnerable plaques and cardiovascular events. Pathology studies reveal that rupture-prone atherosclerotic plaques have a distinct morphology, namely a thin, inflamed fibrous cap covering a large lipidic and necrotic core. With the fast development of imaging techniques in the last decades, detecting vulnerable plaques thereby identifying individuals at high risk for cardiovascular events has become of major interest. Yet, in current clinical practice, there is no routine use of any vascular imaging modality to assess plaque characteristics as each unique technique has its pros and cons. This review describes the techniques that may evolve into screening tool for the detection of the vulnerable plaque. Finally, it seems that plaque morphology has been changing in the last decades leading to a higher prevalence of 'stable' atherosclerotic plaques, possibly due to the implementation of primary prevention strategies or other approaches. Therefore, the nomenclature of vulnerable plaque lesions should be very carefully defined in all studies. PMID:26306911

  7. Inflammation and plaque vulnerability.

    PubMed

    Hansson, G K; Libby, P; Tabas, I

    2015-11-01

    Atherosclerosis is a maladaptive, nonresolving chronic inflammatory disease that occurs at sites of blood flow disturbance. The disease usually remains silent until a breakdown of integrity at the arterial surface triggers the formation of a thrombus. By occluding the lumen, the thrombus or emboli detaching from it elicits ischaemic symptoms that may be life-threatening. Two types of surface damage can cause atherothrombosis: plaque rupture and endothelial erosion. Plaque rupture is thought to be caused by loss of mechanical stability, often due to reduced tensile strength of the collagen cap surrounding the plaque. Therefore, plaques with reduced collagen content are thought to be more vulnerable than those with a thick collagen cap. Endothelial erosion, on the other hand, may occur after injurious insults to the endothelium instigated by metabolic disturbance or immune insults. This review discusses the molecular mechanisms involved in plaque vulnerability and the development of atherothrombosis. PMID:26260307

  8. Symptomatic and asymptomatic carotid artery plaque

    PubMed Central

    Mughal, Majid M; Khan, Mohsin K; DeMarco, J Kevin; Majid, Arshad; Shamoun, Fadi; Abela, George S

    2011-01-01

    Carotid atherosclerotic plaques represent both stable and unstable atheromatous lesions. Atherosclerotic plaques that are prone to rupture owing to their intrinsic composition such as a large lipid core, thin fibrous cap and intraplaque hemorrhage are associated with subsequent thromboembolic ischemic events. At least 15–20% of all ischemic strokes are attributable to carotid artery atherosclerosis. Characterization of plaques may enhance the understanding of natural history and ultimately the treatment of atherosclerotic disease. MRI of carotid plaque and embolic signals during transcranial Doppler have identified features beyond luminal stenosis that are predictive of future transient ischemic attacks and stroke. The value of specific therapies to prevent stroke in symptomatic and asymptomatic patients with severe carotid artery stenosis are the subject of current research and analysis of recently published clinical trials that are discussed in this article. PMID:21985544

  9. Quantification of plaque stiffness by Brillouin microscopy in experimental thin cap fibroatheroma.

    PubMed

    Antonacci, Giuseppe; Pedrigi, Ryan M; Kondiboyina, Avinash; Mehta, Vikram V; de Silva, Ranil; Paterson, Carl; Krams, Rob; Török, Peter

    2015-11-01

    Plaques vulnerable to rupture are characterized by a thin and stiff fibrous cap overlaying a soft lipid-rich necrotic core. The ability to measure local plaque stiffness directly to quantify plaque stress and predict rupture potential would be very attractive, but no current technology does so. This study seeks to validate the use of Brillouin microscopy to measure the Brillouin frequency shift, which is related to stiffness, within vulnerable plaques. The left carotid artery of an ApoE(-/-)mouse was instrumented with a cuff that induced vulnerable plaque development in nine weeks. Adjacent histological sections from the instrumented and control arteries were stained for either lipids or collagen content, or imaged with confocal Brillouin microscopy. Mean Brillouin frequency shift was 15.79 ± 0.09 GHz in the plaque compared with 16.24 ± 0.15 (p < 0.002) and 17.16 ± 0.56 GHz (p < 0.002) in the media of the diseased and control vessel sections, respectively. In addition, frequency shift exhibited a strong inverse correlation with lipid area of -0.67 ± 0.06 (p < 0.01) and strong direct correlation with collagen area of 0.71 ± 0.15 (p < 0.05). This is the first study, to the best of our knowledge, to apply Brillouin spectroscopy to quantify atherosclerotic plaque stiffness, which motivates combining this technology with intravascular imaging to improve detection of vulnerable plaques in patients. PMID:26559685

  10. Modern supragingival plaque control.

    PubMed

    Iacono, V J; Aldredge, W A; Lucks, H; Schwartzstein, S

    1998-06-01

    Supragingival plaque control is essential for the maintenance of oral health. Despite the many chemotherapeutic agents available as mouthrinses and toothpastes, mechanical plaque removal is still the best method to achieve effective plaque control. This is due, in part, to the lack of development of oral antimicrobials with the effectiveness and substantivity of chlorhexidine gluconate but without its adverse effects of dental staining and calculus formation. The use of the numerous mechanical (manual and electric) oral hygiene devices extant and their effectiveness, however, are dependent upon patient dexterity and compliance and concomitant active professional treatment for the monitoring of home care, oral hygiene instruction and patient motivation. This paper evaluates the current methods available to reduce plaque and gingivitis with emphasis on their effectiveness at both supragingival plaque control and disease prevention. In addition, recent studies on the newer oscillating/rotating electric plaque removers and interdental cleaning devices will be discussed as related to their efficacy and compliance. PMID:9779111

  11. Reconsidering the Current Preterm Premature Rupture of Membranes Antibiotic Prophylactic Protocol.

    PubMed

    Wolf, Maya Frank; Miron, Dan; Peleg, David; Rechnitzer, Hagai; Portnov, Igor; Salim, Raed; Keness, Yoram; Reich, Dan; Ami, Moshe Ben; Peretz, Avi; Koshnir, Amir; Shachar, Inbar Ben

    2015-11-01

    Objective?The purpose of our study was to determine whether the current antibiotic regimen for preterm premature rupture of membranes (PPROM) is adequate for covering the current causative agents and sensitivities of chorioamnionitis and early-onset neonatal sepsis. Study Design?During a 3-year period, we retrieved the results from placental and amniotic membrane cultures obtained at delivery in cases of maternal fever, chorioamnionitis, and PPROM, and from blood cultures obtained from neonates with early-onset sepsis (EOS) in three participating hospitals. Sensitivity of pathogens to antimicrobial agents was performed using routine microbiologic techniques. Results?There were 1,133 positive placental or amniotic cultures, 740 (65.3%) were from gram-negative Enterobacteriaceae. There were 27 neonates diagnosed with EOS with positive blood cultures. Aerobic Enterobacteriaceae accounted for 14 cases (52%) and group B streptococcus for 7 cases (26%). Of the Escherichia coli and Klebsiella sp., only 38% were sensitive to ampicillin. Conclusion?Local pathogens and their antibiotic sensitivity profiles should be explored every few years and an effective antibiotic protocol chosen to cover the main pathogens causing chorioamnionitis and EOS. Consideration should be made for changing ampicillin in women with PPROM to a regimen with better coverage of gram-negative Enterobacteriaceae. PMID:26023907

  12. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation

    PubMed Central

    Tang, Jun; Lobatto, Mark E.; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M.; Calcagno, Claudia; Braza, Mounia S.; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L.; Duivenvoorden, Raphaël; Sager, Hendrik B.; Astudillo, Yaritzy M.; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P.; Strijkers, Gustav J.; Stroes, Erik S. G.; Swirski, Filip K.; Nahrendorf, Matthias; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2015-01-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E–deficient mice (Apoe−/−) with advanced atherosclerotic plaques. This resulted in the rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an 8-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis. PMID:26295063

  13. Image-Based Modeling and Precision Medicine: Patient-Specific Carotid and Coronary Plaque Assessment and Predictions

    PubMed Central

    Yang, Chun; Zheng, Jie; Canton, Gador; Bach, Richard; Hatsukami, Thomas S.; Wang, Liang; Yang, Deshan; Billiar, Kristen L.; Yuan, Chun

    2013-01-01

    Atherosclerotic plaques may rupture without warning and cause acute cardiovascular events such as heart attack and stroke. Current clinical screening tools are insufficient to identify those patients with risks early and prevent the adverse events from happening. Medical imaging and image-based modeling have made considerable progress in recent years in identifying plaque morphological and mechanical risk factors which may be used in developing improved patient screening strategies. The key steps and factors in image-based models for human carotid and coronary plaques were illustrated, as well as grand challenges facing the researchers in the field to develop more accurate screening tools. PMID:23362245

  14. Compressive mechanical properties of atherosclerotic plaques--indentation test to characterise the local anisotropic behaviour.

    PubMed

    Chai, Chen-Ket; Speelman, Lambert; Oomens, Cees W J; Baaijens, Frank P T

    2014-03-01

    Accurate material models and associated parameters of atherosclerotic plaques are crucial for reliable biomechanical plaque prediction models. These biomechanical models have the potential to increase our understanding of plaque progression and failure, possibly improving risk assessment of plaque rupture, which is the main cause of ischaemic strokes and myocardial infarction. However, experimental biomechanical data on atherosclerotic plaque tissue is scarce and shows a high variability. In addition, most of the biomechanical models assume isotropic behaviour of plaque tissue, which is a general over-simplification. This review discusses the past and the current literature that focus on mechanical properties of plaque derived from compression experiments, using unconfined compression, micro-indentation or nano-indentation. Results will be discussed and the techniques will be mutually compared. Thereafter, an in-house developed indentation method combined with an inverse finite element method is introduced, allowing analysis of the local anisotropic mechanical properties of atherosclerotic plaques. The advantages and limitations of this method will be evaluated and compared to other methods reported in literature. PMID:24480703

  15. Analysis of Multicontrast Carotid Plaque MR Imaging.

    PubMed

    Chen, Huijun; Zhang, Qiang; Kerwin, William

    2016-02-01

    Plaque imaging by MR imaging provides a wealth of information on the characteristics of individual plaque that may reveal vulnerability to rupture, likelihood of progression, or optimal treatment strategy. T1-weighted and T2-weighted images among other options reveal plaque morphology and composition. Dynamic contrast-enhanced-MR imaging reveals plaque activity. To extract this information, image processing tools are needed. Numerous approaches for analyzing such images have been developed, validated against histologic gold standards, and used in clinical studies. These efforts are summarized in this article. PMID:26610657

  16. Contemporary carotid imaging: from degree of stenosis to plaque vulnerability.

    PubMed

    Brinjikji, Waleed; Huston, John; Rabinstein, Alejandro A; Kim, Gyeong-Moon; Lerman, Amir; Lanzino, Giuseppe

    2016-01-01

    Carotid artery stenosis is a well-established risk factor of ischemic stroke, contributing to up to 10%-20% of strokes or transient ischemic attacks. Many clinical trials over the last 20 years have used measurements of carotid artery stenosis as a means to risk stratify patients. However, with improvements in vascular imaging techniques such as CT angiography and MR angiography, ultrasonography, and PET/CT, it is now possible to risk stratify patients, not just on the degree of carotid artery stenosis but also on how vulnerable the plaque is to rupture, resulting in ischemic stroke. These imaging techniques are ushering in an emerging paradigm shift that allows for risk stratifications based on the presence of imaging features such as intraplaque hemorrhage (IPH), plaque ulceration, plaque neovascularity, fibrous cap thickness, and presence of a lipid-rich necrotic core (LRNC). It is important for the neurosurgeon to be aware of these new imaging techniques that allow for improved patient risk stratification and outcomes. For example, a patient with a low-grade stenosis but an ulcerated plaque may benefit more from a revascularization procedure than a patient with a stable 70% asymptomatic stenosis with a thick fibrous cap. This review summarizes the current state-of-the-art advances in carotid plaque imaging. Currently, MRI is the gold standard in carotid plaque imaging, with its high resolution and high sensitivity for identifying IPH, ulceration, LRNC, and inflammation. However, MRI is limited due to time constraints. CT also allows for high-resolution imaging and can accurately detect ulceration and calcification, but cannot reliably differentiate LRNC from IPH. PET/CT is an effective technique to identify active inflammation within the plaque, but it does not allow for assessment of anatomy, ulceration, IPH, or LRNC. Ultrasonography, with the aid of contrast enhancement, is a cost-effective technique to assess plaque morphology and characteristics, but it is limited in sensitivity and specificity for detecting LRNC, plaque hemorrhage, and ulceration compared with MRI. Also summarized is how these advanced imaging techniques are being used in clinical practice to risk stratify patients with low- and high-grade carotid artery stenosis. For example, identification of IPH on MRI in patients with low-grade carotid artery stenosis is a risk factor for failure of medical therapy, and studies have shown that such patients may fair better with carotid endarterectomy (CEA). MR plaque imaging has also been found to be useful in identifying revascularization candidates who would be better candidates for CEA than carotid artery stenting (CAS), as high intraplaque signal on time of flight imaging is associated with vulnerable plaque and increased rates of adverse events in patients undergoing CAS but not CEA. PMID:26230478

  17. Ultrasound Tissue Characterization of Vulnerable Atherosclerotic Plaque

    PubMed Central

    Picano, Eugenio; Paterni, Marco

    2015-01-01

    A thrombotic occlusion of the vessel fed by ruptured coronary atherosclerotic plaque may result in unstable angina, myocardial infarction or death, whereas embolization from a plaque in carotid arteries may result in transient ischemic attack or stroke. The atherosclerotic plaque prone to such clinical events is termed high-risk or vulnerable plaque, and its identification in humans before it becomes symptomatic has been elusive to date. Ultrasonic tissue characterization of the atherosclerotic plaque is possible with different techniques—such as vascular, transesophageal, and intravascular ultrasound—on a variety of arterial segments, including carotid, aorta, and coronary districts. The image analysis can be based on visual, video-densitometric or radiofrequency methods and identifies three distinct textural patterns: hypo-echoic (corresponding to lipid- and hemorrhage-rich plaque), iso- or moderately hyper-echoic (fibrotic or fibro-fatty plaque), and markedly hyperechoic with shadowing (calcific plaque). Hypoechoic or dishomogeneous plaques, with spotty microcalcification and large plaque burden, with plaque neovascularization and surface irregularities by contrast-enhanced ultrasound, are more prone to clinical complications than hyperechoic, extensively calcified, homogeneous plaques with limited plaque burden, smooth luminal plaque surface and absence of neovascularization. Plaque ultrasound morphology is important, along with plaque geometry, in determining the atherosclerotic prognostic burden in the individual patient. New quantitative methods beyond backscatter (to include speed of sound, attenuation, strain, temperature, and high order statistics) are under development to evaluate vascular tissues. Although not yet ready for widespread clinical use, tissue characterization is listed by the American Society of Echocardiography roadmap to 2020 as one of the most promising fields of application in cardiovascular ultrasound imaging, offering unique opportunities for the early detection and treatment of atherosclerotic disease. PMID:25950760

  18. Ultrasound tissue characterization of vulnerable atherosclerotic plaque.

    PubMed

    Picano, Eugenio; Paterni, Marco

    2015-01-01

    A thrombotic occlusion of the vessel fed by ruptured coronary atherosclerotic plaque may result in unstable angina, myocardial infarction or death, whereas embolization from a plaque in carotid arteries may result in transient ischemic attack or stroke. The atherosclerotic plaque prone to such clinical events is termed high-risk or vulnerable plaque, and its identification in humans before it becomes symptomatic has been elusive to date. Ultrasonic tissue characterization of the atherosclerotic plaque is possible with different techniques--such as vascular, transesophageal, and intravascular ultrasound--on a variety of arterial segments, including carotid, aorta, and coronary districts. The image analysis can be based on visual, video-densitometric or radiofrequency methods and identifies three distinct textural patterns: hypo-echoic (corresponding to lipid- and hemorrhage-rich plaque), iso- or moderately hyper-echoic (fibrotic or fibro-fatty plaque), and markedly hyperechoic with shadowing (calcific plaque). Hypoechoic or dishomogeneous plaques, with spotty microcalcification and large plaque burden, with plaque neovascularization and surface irregularities by contrast-enhanced ultrasound, are more prone to clinical complications than hyperechoic, extensively calcified, homogeneous plaques with limited plaque burden, smooth luminal plaque surface and absence of neovascularization. Plaque ultrasound morphology is important, along with plaque geometry, in determining the atherosclerotic prognostic burden in the individual patient. New quantitative methods beyond backscatter (to include speed of sound, attenuation, strain, temperature, and high order statistics) are under development to evaluate vascular tissues. Although not yet ready for widespread clinical use, tissue characterization is listed by the American Society of Echocardiography roadmap to 2020 as one of the most promising fields of application in cardiovascular ultrasound imaging, offering unique opportunities for the early detection and treatment of atherosclerotic disease. PMID:25950760

  19. The Use of Contrast-enhanced Ultrasonography for Imaging of Carotid Atherosclerotic Plaques: Current Evidence, Future Directions.

    PubMed

    Saha, Sandeep A; Gourineni, Venu; Feinstein, Steven B

    2016-02-01

    Contrast-enhanced ultrasonography (CEUS) is a rapidly evolving modality for imaging carotid artery disease and systemic atherosclerosis. CEUS coupled with diagnostic ultrasonography predicts the degree of carotid artery stenosis and is comparable with computed tomography and magnetic resonance angiography. This article reviews the literature on the evolving role of CEUS for the identification and characterization of carotid plaques with an emphasis on detection of intra-plaque neovascularization and related high-risk morphologic features notably present in symptomatic patients. CEUS carotid imaging may play a prominent additive role in risk stratifying patients and serve as a powerful tool for monitoring therapeutic interventions. PMID:26610662

  20. Radionuclide imaging - A molecular key to the atherosclerotic plaque

    PubMed Central

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

    2008-01-01

    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

  1. Effects of bacteriophage traits on plaque formation

    PubMed Central

    2011-01-01

    Background The appearance of plaques on a bacterial lawn is one of the enduring imageries in modern day biology. The seeming simplicity of a plaque has invited many hypotheses and models in trying to describe and explain the details of its formation. However, until now, there has been no systematic experimental exploration on how different bacteriophage (phage) traits may influence the formation of a plaque. In this study, we constructed a series of isogenic ? phages that differ in their adsorption rate, lysis timing, or morphology so that we can determine the effects if these changes on three plaque properties: size, progeny productivity, and phage concentration within plaques. Results We found that the adsorption rate has a diminishing, but negative impact on all three plaque measurements. Interestingly, there exists a concave relationship between the lysis time and plaque size, resulting in an apparent optimal lysis time that maximizes the plaque size. Although suggestive in appearance, we did not detect a significant effect of lysis time on plaque productivity. Nonetheless, the combined effects of plaque size and productivity resulted in an apparent convex relationship between the lysis time and phage concentration within plaques. Lastly, we found that virion morphology also affected plaque size. We compared our results to the available models on plaque size and productivity. For the models in their current forms, a few of them can capture the qualitative aspects of our results, but not consistently in both plaque properties. Conclusions By using a collection of isogenic phage strains, we were able to investigate the effects of individual phage traits on plaque size, plaque productivity, and average phage concentration in a plaque while holding all other traits constant. The controlled nature of our study allowed us to test several model predictions on plaque size and plaque productivity. It seems that a more realistic theoretical approach to plaque formation is needed in order to capture the complex interaction between phage and its bacterium host in a spatially restricted environment. PMID:21827665

  2. Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo.

    PubMed

    Li, Jiawen; Ma, Teng; Mohar, Dilbahar; Steward, Earl; Yu, Mingyue; Piao, Zhonglie; He, Youmin; Shung, K Kirk; Zhou, Qifa; Patel, Pranav M; Chen, Zhongping

    2015-01-01

    Atherosclerotic coronary artery disease (CAD) is the number one cause of death worldwide. The majority of CAD-induced deaths are due to the rupture of vulnerable plaques. Accurate assessment of plaques is crucial to optimize treatment and prevent death in patients with CAD. Current diagnostic techniques are often limited by either spatial resolution or penetration depth. Several studies have proved that the combined use of optical and ultrasonic imaging techniques increase diagnostic accuracy of vulnerable plaques. Here, we introduce an ultrafast optical-ultrasonic dual-modality imaging system and flexible miniaturized catheter, which enables the translation of this technology into clinical practice. This system can perform simultaneous optical coherence tomography (OCT)-intravascular ultrasound (IVUS) imaging at 72 frames per second safely in vivo, i.e., visualizing a 72?mm-long artery in 4?seconds. Results obtained in atherosclerotic rabbits in vivo and human coronary artery segments show that this ultrafast technique can rapidly provide volumetric mapping of plaques and clearly identify vulnerable plaques. By providing ultrafast imaging of arteries with high resolution and deep penetration depth simultaneously, this hybrid IVUS-OCT technology opens new and safe opportunities to evaluate in real-time the risk posed by plaques, detect vulnerable plaques, and optimize treatment decisions. PMID:26678300

  3. Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo

    PubMed Central

    Li, Jiawen; Ma, Teng; Mohar, Dilbahar; Steward, Earl; Yu, Mingyue; Piao, Zhonglie; He, Youmin; Shung, K. Kirk; Zhou, Qifa; Patel, Pranav M.; Chen, Zhongping

    2015-01-01

    Atherosclerotic coronary artery disease (CAD) is the number one cause of death worldwide. The majority of CAD-induced deaths are due to the rupture of vulnerable plaques. Accurate assessment of plaques is crucial to optimize treatment and prevent death in patients with CAD. Current diagnostic techniques are often limited by either spatial resolution or penetration depth. Several studies have proved that the combined use of optical and ultrasonic imaging techniques increase diagnostic accuracy of vulnerable plaques. Here, we introduce an ultrafast optical-ultrasonic dual-modality imaging system and flexible miniaturized catheter, which enables the translation of this technology into clinical practice. This system can perform simultaneous optical coherence tomography (OCT)-intravascular ultrasound (IVUS) imaging at 72 frames per second safely in vivo, i.e., visualizing a 72 mm-long artery in 4 seconds. Results obtained in atherosclerotic rabbits in vivo and human coronary artery segments show that this ultrafast technique can rapidly provide volumetric mapping of plaques and clearly identify vulnerable plaques. By providing ultrafast imaging of arteries with high resolution and deep penetration depth simultaneously, this hybrid IVUS-OCT technology opens new and safe opportunities to evaluate in real-time the risk posed by plaques, detect vulnerable plaques, and optimize treatment decisions. PMID:26678300

  4. 3D MRI-Based Anisotropic FSI Models with Cyclic Bending for Human Coronary Atherosclerotic Plaque Mechanical Analysis

    PubMed Central

    Tang, Dalin; Yang, Chun; Kobayashi, Shunichi; Zheng, Jie; Woodard, Pamela K.; Teng, Zhongzhao; Billiar, Kristen; Bach, Richard; Ku, David N.

    2009-01-01

    Background Heart attack and stroke are often caused by atherosclerotic plaque rupture which happens without warning most of the time. MRI-based atherosclerotic plaque models with fluid-structure interactions (FSI) have been introduced to perform flow and stress/strain analysis and identify possible mechanical and morphological indices for accurate plaque vulnerability assessment. For coronary arteries, cyclic bending associated with heart motion and anisotropy of the vessel walls may have significant influence on flow and stress/strain distributions in the plaque. FSI models with cyclic bending and anisotropic vessel properties for coronary plaques are lacking in the current literature. Method of Approach In this paper, cyclic bending and anisotropic vessel properties were added to 3D FSI coronary plaque models so that the models would be more realistic for more accurate computational flow and stress/strain predictions. Six computational models using one ex vivo MRI human coronary plaque specimen data were constructed to assess the effects of cyclic bending, anisotropic vessel properties, pulsating pressure, plaque structure, and axial stretch on plaque stress/strain distributions. Results Our results indicate that cyclic bending and anisotropic properties may cause 50%–800% increase in maximum principal stress (Stress-P1) values at selected locations. The stress increase varies with location and is higher when bending is coupled with axial stretch, non-smooth plaque structure, and resonant pressure conditions (zero phase angle shift). Effects of cyclic bending on flow behaviors are more modest (9.8% decrease in maximum velocity, 2.5% decrease in flow rate, 15% increase in maximum flow shear stress). Conclusions Inclusion of cyclic bending, anisotropic vessel material properties, accurate plaque structure, and axial stretch in computational FSI models should lead to considerable improvement of accuracy of computational stress/strain predictions for coronary plaque vulnerability assessment. Further studies incorporating additional mechanical property data and in vivo MRI data are needed to obtain more complete and accurate knowledge about flow and stress/strain behaviors in coronary plaques and to identify critical indicators for better plaque assessment and possible rupture predictions. PMID:19449964

  5. Comprehensive plaque assessment by coronary CT angiography.

    PubMed

    Maurovich-Horvat, Pál; Ferencik, Maros; Voros, Szilard; Merkely, Béla; Hoffmann, Udo

    2014-07-01

    Most acute coronary syndromes are caused by sudden luminal thrombosis due to atherosclerotic plaque rupture or erosion. Preventing such an event seems to be the only effective strategy to reduce mortality and morbidity of coronary heart disease. Coronary lesions prone to rupture have a distinct morphology compared with stable plaques, and provide a unique opportunity for noninvasive imaging to identify vulnerable plaques before they lead to clinical events. The submillimeter spatial resolution and excellent image quality of modern computed tomography (CT) scanners allow coronary atherosclerotic lesions to be detected, characterized, and quantified. Large plaque volume, low CT attenuation, napkin-ring sign, positive remodelling, and spotty calcification are all associated with a high risk of acute cardiovascular events in patients. Computation fluid dynamics allow the calculation of lesion-specific endothelial shear stress and fractional flow reserve, which add functional information to plaque assessment using CT. The combination of morphologic and functional characteristics of coronary plaques might enable noninvasive detection of vulnerable plaques in the future. PMID:24755916

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

    PubMed Central

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

    2014-01-01

    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

  7. Multiphoton microscopy of atheroslcerotic plaques

    NASA Astrophysics Data System (ADS)

    Lilledahl, Magnus B.; de Lange Davies, Catharina; Haugen, Olav A.; Svaasand, Lars O.

    2007-02-01

    Multiphoton microscopy is a techniques that fascilitates three dimensional imaging of intact, unstained tissue. Especially connective tissue has a relatively strong nonlinear optical response and can easily be imaged. Atherosclerosis is a disease where lipids accumulate in the vessel wall and there is a thickening of the intima by growth of a cap of connective tissue. The mechanical strength of this fibrous cap is of clinically importance. If the cap ruptures a thrombosis forms which can block a coronary vessel and therby causing myocardial infarction. Multiphoton microscopy can be used to image the fibrous cap and thereby determine the thickness of the cap and the structure of the connective fibres. This could possibly be developed into a diagnostic and clincal tool to monitor the vulnerability of a plaque and also to better understand the development of a plaque and effects of treatment. We have collected multiphoton microscopy images from atherosclerotic plaque in human aorta, both two photon excited fluorescens and second harmonic generated signal. The feasability of using this technique to determine the state of the plaque is explored.

  8. Nuclear Molecular Imaging for Vulnerable Atherosclerotic Plaques

    PubMed Central

    Lee, Soo Jin

    2015-01-01

    Atherosclerosis is an inflammatory disease as well as a lipid disorder. Atherosclerotic plaque formed in vessel walls may cause ischemia, and the rupture of vulnerable plaque may result in fatal events, like myocardial infarction or stroke. Because morphological imaging has limitations in diagnosing vulnerable plaque, molecular imaging has been developed, in particular, the use of nuclear imaging probes. Molecular imaging targets various aspects of vulnerable plaque, such as inflammatory cell accumulation, endothelial activation, proteolysis, neoangiogenesis, hypoxia, apoptosis, and calcification. Many preclinical and clinical studies have been conducted with various imaging probes and some of them have exhibited promising results. Despite some limitations in imaging technology, molecular imaging is expected to be used both in the research and clinical fields as imaging instruments become more advanced. PMID:26357491

  9. Vascular MR segmentation: wall and plaque

    NASA Astrophysics Data System (ADS)

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

    2003-05-01

    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.

  10. Nature or The Natural Evolution of Plaque: What Matters?

    PubMed Central

    AURSULESEI, Viviana

    2013-01-01

    ABSTRACT Progression to major acute cardiovascular events often is triggered by an atherosclerotic plaque complicated by rupture or erosion, namely the vulnerable plaque. Early and secure identification of these plaques would allow the development of individualized therapeutic and pharmacological strategies, applied in a timely manner. Imaging methods have a huge potential in detecting and monitoring the evolution of vulnerable plaque. Even though there are multiple invasive and noninvasive techniques, clinical application is for now a matter of choosing the relevant imaging feature for the prognosis, the methodo­logy of study and the target population. PMID:24790659

  11. Local anisotropic mechanical properties of human carotid atherosclerotic plaques - characterisation by micro-indentation and inverse finite element analysis.

    PubMed

    Chai, Chen-Ket; Akyildiz, Ali C; Speelman, Lambert; Gijsen, Frank J H; Oomens, Cees W J; van Sambeek, Marc R H M; van der Lugt, Aad; Baaijens, Frank P T

    2015-03-01

    Biomechanical models have the potential to predict failure of atherosclerotic plaques and to improve the risk assessment of plaque rupture. The applicability of these models depends strongly on the used material models. Current biomechanical models employ isotropic material models, although it is generally accepted that plaque tissue behaves highly anisotropic. The aim of the present study is to determine the local anisotropic mechanical properties of human atherosclerotic plaque tissue by means of micro-indentation tests. The indentation was performed on top of an inverted confocal microscope allowing the visualisation and quantification of the collagen fibre deformations perpendicular to the indentation direction of the plaque. Based on this, the anisotropic properties of plaque tissue perpendicular to the indentation direction (middle of the fibrous cap, shoulder of the cap, remaining intima tissue) were derived. There were no significant differences between the different indentation locations for the fibre stiffness (total median 80.6kPa, 25th-75th percentile 17.7-157.0kPa), and fibre dispersion. PMID:25553556

  12. The nature of iron deposits differs between symptomatic and asymptomatic carotid atherosclerotic plaques

    DOE PAGESBeta

    Kopriva, David; Kisheev, Anastasye; Meena, Deiter; Pelle, Shaneen; Karnitsky, Max; Lavoie, Andrea; Buttigieg, Josef; Hagemeyer, Christoph E.

    2015-11-25

    Iron within atherosclerotic plaque has been implicated as a catalyst of oxidative stress that causes progression of plaque, and plaque rupture. Iron is believed to accumulate within plaque by incorporation of erythrocytes following plaque rupture and hemorrhage. There is only indirect evidence to support this hypothesis. Plaque specimens were obtained from ten symptomatic and fifteen asymptomatic patients undergoing carotid endarterectomy at a single institution. Plaques were sectioned for study using synchrotron radiation induced X-ray fluorescence the study the distribution of zinc, calcium and iron. Histologic staining was carried out with Prussian Blue, and immunohistochemical staining was done to localize macrophagesmore » with CD68. Data were compared against patient clinical variables. Ten symptomatic (15 ± 10 days between index symptoms and surgery) and fifteen asymptomatic carotid plaques were studied. Zinc and calcium co-localized in mineralized areas of symptomatic and asymptomatic plaque. Iron was identified away from zinc and calcium in both symptomatic and asymptomatic plaques. Within the symptomatic plaques, iron was found within the thrombus associated with plaque rupture and hemorrhage. It did not stain with Prussian Blue, but was found in association with CD68 positive macrophages. In symptomatic plaques, the abundance of iron showed an association with the source patient’s LDL cholesterol (R2 = 0.39, Significance F = 0.05). Iron in asymptomatic plaque was present as hemosiderin/ferritin that stained positive with Prussian Blue, and was observed in association with CD68 positive macrophages. Iron in acutely symptomatic plaques is found within thrombus, in the presence of macrophages. Moreover, the abundance of iron in symptomatic plaques is associated with the source patient’s LDL cholesterol. Within asymptomatic plaques, iron is found in association with macrophages, as hemosiderin/ferritin.« less

  13. The nature of iron deposits differs between symptomatic and asymptomatic carotid atherosclerotic plaques

    SciTech Connect

    Kopriva, David; Kisheev, Anastasye; Meena, Deiter; Pelle, Shaneen; Karnitsky, Max; Lavoie, Andrea; Buttigieg, Josef; Hagemeyer, Christoph E.

    2015-11-25

    Iron within atherosclerotic plaque has been implicated as a catalyst of oxidative stress that causes progression of plaque, and plaque rupture. Iron is believed to accumulate within plaque by incorporation of erythrocytes following plaque rupture and hemorrhage. There is only indirect evidence to support this hypothesis. Plaque specimens were obtained from ten symptomatic and fifteen asymptomatic patients undergoing carotid endarterectomy at a single institution. Plaques were sectioned for study using synchrotron radiation induced X-ray fluorescence the study the distribution of zinc, calcium and iron. Histologic staining was carried out with Prussian Blue, and immunohistochemical staining was done to localize macrophages with CD68. Data were compared against patient clinical variables. Ten symptomatic (15 ± 10 days between index symptoms and surgery) and fifteen asymptomatic carotid plaques were studied. Zinc and calcium co-localized in mineralized areas of symptomatic and asymptomatic plaque. Iron was identified away from zinc and calcium in both symptomatic and asymptomatic plaques. Within the symptomatic plaques, iron was found within the thrombus associated with plaque rupture and hemorrhage. It did not stain with Prussian Blue, but was found in association with CD68 positive macrophages. In symptomatic plaques, the abundance of iron showed an association with the source patient’s LDL cholesterol (R2 = 0.39, Significance F = 0.05). Iron in asymptomatic plaque was present as hemosiderin/ferritin that stained positive with Prussian Blue, and was observed in association with CD68 positive macrophages. Iron in acutely symptomatic plaques is found within thrombus, in the presence of macrophages. Moreover, the abundance of iron in symptomatic plaques is associated with the source patient’s LDL cholesterol. Within asymptomatic plaques, iron is found in association with macrophages, as hemosiderin/ferritin.

  14. The Nature of Iron Deposits Differs between Symptomatic and Asymptomatic Carotid Atherosclerotic Plaques

    PubMed Central

    Kopriva, David; Kisheev, Anastasye; Meena, Deiter; Pelle, Shaneen; Karnitsky, Max; Lavoie, Andrea; Buttigieg, Josef

    2015-01-01

    Iron within atherosclerotic plaque has been implicated as a catalyst of oxidative stress that causes progression of plaque, and plaque rupture. Iron is believed to accumulate within plaque by incorporation of erythrocytes following plaque rupture and hemorrhage. There is only indirect evidence to support this hypothesis. Plaque specimens were obtained from ten symptomatic and fifteen asymptomatic patients undergoing carotid endarterectomy at a single institution. Plaques were sectioned for study using synchrotron radiation induced X-ray fluorescence the study the distribution of zinc, calcium and iron. Histologic staining was carried out with Prussian Blue, and immunohistochemical staining was done to localize macrophages with CD68. Data were compared against patient clinical variables. Ten symptomatic (15 ± 10 days between index symptoms and surgery) and fifteen asymptomatic carotid plaques were studied. Zinc and calcium co-localized in mineralized areas of symptomatic and asymptomatic plaque. Iron was identified away from zinc and calcium in both symptomatic and asymptomatic plaques. Within the symptomatic plaques, iron was found within the thrombus associated with plaque rupture and hemorrhage. It did not stain with Prussian Blue, but was found in association with CD68 positive macrophages. In symptomatic plaques, the abundance of iron showed an association with the source patient’s LDL cholesterol (R2 = 0.39, Significance F = 0.05). Iron in asymptomatic plaque was present as hemosiderin/ferritin that stained positive with Prussian Blue, and was observed in association with CD68 positive macrophages. Iron in acutely symptomatic plaques is found within thrombus, in the presence of macrophages. The abundance of iron in symptomatic plaques is associated with the source patient’s LDL cholesterol. Within asymptomatic plaques, iron is found in association with macrophages, as hemosiderin/ferritin. PMID:26606178

  15. Angiopoietin-2 blocking antibodies reduce early atherosclerotic plaque development in mice

    PubMed Central

    Theelen, Thomas L.; Lappalainen, Jari P.; Sluimer, Judith C.; Gurzeler, Erika; Cleutjens, Jack P.; Gijbels, Marion J.; Biessen, Erik A.L.; Daemen, Mat J.A.P.; Alitalo, Kari; Ylä-Herttuala, Seppo

    2015-01-01

    Objective Angiopoietin-2 (Ang-2) blocking agents are currently undergoing clinical trials for use in cancer treatment. Ang-2 has also been associated with rupture-prone atherosclerotic plaques in humans, suggesting a role for Ang-2 in plaque stability. Despite the availability of Ang-2 blocking agents, their clinical use is still lacking. Our aim was to establish if Ang-2 has a role in atheroma development and in the transition of subclinical to clinically relevant atherosclerosis. We investigated the effect of antibody-mediated Ang-2 blockage on atherogenesis after in a mouse model of atherosclerosis. Methods Hypercholesterolemic (low-density lipoprotein receptor−/− apolipoprotein B100/100) mice were subjected to high-cholesterol diet for eight weeks, one group with and one group without Ang-2 blocking antibody treatment during weeks 4–8.To enhance plaque development, a peri-adventitial collar was placed around the carotid arteries at the start of antibody treatment. Aortic root, carotid arteries and brachiocephalic arteries were analyzed to evaluate the effect of Ang-2 blockage on atherosclerotic plaque size and stable plaque characteristics. Results Anti-Ang-2 treatment reduced the size of fatty streaks in the brachiocephalic artery (−72%, p < 0.05). In addition, antibody-mediated Ang-2 blockage reduced plasma triglycerides (−27%, p < 0.05). In contrast, Ang-2 blockage did not have any effect on the size or composition (collagen content, macrophage percentage, adventitial microvessel density) of pre-existing plaques in the aortic root or collar-induced plaques in the carotid artery. Conclusions Ang-2 blockage was beneficial as it decreased fatty streak formation and plasma triglyceride levels, but had no adverse effect on pre-existing atherosclerosis in hypercholesterolemic mice. PMID:26062989

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

    NASA Astrophysics Data System (ADS)

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

    2006-02-01

    Current evidence indicates that most plaques classified as vulnerable or ruptured plaques 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 use polarization sensitive optical coherence tomography (PS-OCT) for the assessment of coronary plaque collagen. Collagen is birefringent, meaning that different polarization states travel through it at different velocities. Changes in PS-OCT images are a measure of tissue birefringence. Twenty-two coronary artery segments were imaged with PS-OCT and analyzed by picrosirius staining (a measure of collagen intensity and fiber size) and trichrome blue. The regression plot between PS-OCT changes and measured collagen yielded a correlation coefficient value of 0.475 (p<0.002). Good correlation was noted between two blinded investigators both with respect to PS-OCT measurements as well as luminosity as assessed by picrosirius. The predictive value of a PS-OCT measurement of negligible birefringence (less than 33% change) for minimal collagen was 93% while the predictive value of high birefringence (greater than 66% change) for high collagen concentrations was 89%. The effect of fiber type (chemical composition) was minimal relative to the effect due to fiber concentration. The capability of PS-OCT to assess plaque collagen content, in addition to its ability to generate high resolution structural assessments, make it a potentially powerful technology for identifying high risk plaques.

  17. Experimental determination of circumferential properties of fresh carotid artery plaques.

    PubMed

    Lawlor, Michael G; O'Donnell, Michael R; O'Connell, Barry M; Walsh, Michael T

    2011-06-01

    Carotid endarterectomy (CEA) is currently accepted as the gold standard for interventional revascularisation of diseased arteries belonging to the carotid bifurcation. Despite the proven efficacy of CEA, great interest has been generated in carotid angioplasty and stenting (CAS) as an alternative to open surgical therapy. CAS is less invasive compared with CEA, and has the potential to successfully treat lesions close to the aortic arch or distal internal carotid artery (ICA). Following promising results from two recent trials (CREST; Carotid revascularisation endarterectomy versus stenting trial, and ICSS; International carotid stenting study) it is envisaged that there will be a greater uptake in carotid stenting, especially amongst the group who do not qualify for open surgical repair, thus creating pressure to develop computational models that describe a multitude of plaque models in the carotid arteries and their reaction to the deployment of such interventional devices. Pertinent analyses will require fresh human atherosclerotic plaque material characteristics for different disease types. This study analysed atherosclerotic plaque characteristics from 18 patients tested on site, post-surgical revascularisation through endarterectomy, with 4 tissue samples being excluded from tensile testing based on large width-length ratios. According to their mechanical behaviour, atherosclerotic plaques were separated into 3 grades of stiffness. Individual and group material coefficients were then generated analytically using the Yeoh strain energy function. The ultimate tensile strength (UTS) of each sample was also recorded, showing large variation across the 14 atherosclerotic samples tested. Experimental Green strains at rupture varied from 0.299 to 0.588 and the Cauchy stress observed in the experiments was between 0.131 and 0.779 MPa. It is expected that this data may be used in future design optimisation of next generation interventional medical devices for the treatment and revascularisation of diseased arteries of the carotid bifurcation. PMID:21497353

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

    PubMed

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

    2014-01-01

    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

  19. Ultrafast laser ablation for targeted atherosclerotic plaque removal

    NASA Astrophysics Data System (ADS)

    Lanvin, Thomas; Conkey, Donald B.; Descloux, Laurent; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-07-01

    Coronary artery disease, the main cause of heart disease, develops as immune cells and lipids accumulate into plaques within the coronary arterial wall. As a plaque grows, the tissue layer (fibrous cap) separating it from the blood flow becomes thinner and increasingly susceptible to rupturing and causing a potentially lethal thrombosis. The stabilization and/or treatment of atherosclerotic plaque is required to prevent rupturing and remains an unsolved medical problem. Here we show for the first time targeted, subsurface ablation of atherosclerotic plaque using ultrafast laser pulses. Excised atherosclerotic mouse aortas were ablated with ultrafast near-infrared (NIR) laser pulses. The physical damage was characterized with histological sections of the ablated atherosclerotic arteries from six different mice. The ultrafast ablation system was integrated with optical coherence tomography (OCT) imaging for plaque-specific targeting and monitoring of the resulting ablation volume. We find that ultrafast ablation of plaque just below the surface is possible without causing damage to the fibrous cap, which indicates the potential use of ultrafast ablation for subsurface atherosclerotic plaque removal. We further demonstrate ex vivo subsurface ablation of a plaque volume through a catheter device with the high-energy ultrafast pulse delivered via hollow-core photonic crystal fiber.

  20. Rupture disc

    DOEpatents

    Newton, Robert G.

    1977-01-01

    The intermediate heat transport system for a sodium-cooled fast breeder reactor includes a device for rapidly draining the sodium therefrom should a sodium-water reaction occur within the system. This device includes a rupturable member in a drain line in the system and means for cutting a large opening therein and for positively removing the sheared-out portion from the opening cut in the rupturable member. According to the preferred embodiment of the invention the rupturable member includes a solid head seated in the end of the drain line having a rim extending peripherally therearound, the rim being clamped against the end of the drain line by a clamp ring having an interior shearing edge, the bottom of the rupturable member being convex and extending into the drain line. Means are provided to draw the rupturable member away from the drain line against the shearing edge to clear the drain line for outflow of sodium therethrough.

  1. Vulnerable atherosclerotic plaque metalloproteinases and foam cell phenotypes

    PubMed Central

    Newby, Andrew C.; George, Sarah J.; Ismail, Yasmin; Johnson, Jason L.; Sala-Newby, Graciela B.; Thomas, Anita C.

    2010-01-01

    Summary Plaque rupture underlies most myocardial infarctions. Plaques vulnerable to rupture have thin fibrous caps, an excess of macrophages over vascular smooth muscle cells, large lipid cores, and depletion of collagen and other matrix proteins form the cap and lipid core. Production of matrix metalloproteinases from macrophages is prominent in human plaques, and studies in genetically modified mice imply a causative role for metalloproteinases in plaque vulnerability. Recent in-vitro studies on human monocyte-derived macrophages and on foam-cell macrophages generated in vivo suggest the existence of several macrophage phenotypes with distinct patterns of metalloproteinase expression. These phenotypes could play differing roles in cap, core and aneurysm formation. PMID:19492140

  2. Direct association between diet and the stability of human atherosclerotic plaque.

    PubMed

    Gonçalves, Isabel; Andersson Georgiadou, Elisavet; Mattsson, Sören; Skog, Göran; Pedro, Luís; Fernandes E Fernandes, José; Dias, Nuno; Engström, Gunnar; Nilsson, Jan; Stenström, Kristina

    2015-01-01

    Mediterranean diet has been suggested to explain why coronary heart disease mortality is lower in southern than northern Europe. Dietary habits can be revealed by isotope ratio mass spectrometry (IRMS) measurement of carbon (?(13)C) and nitrogen (?(15)N) in biological tissues. To study if diet is associated with human plaque stability, atherosclerotic plaques from carotid endarterectomy on 56 patients (21 Portuguese and 35 Swedish) were analysed by IRMS and histology. Plaque components affecting rupture risk were measured. Swedish plaques had more apoptosis, lipids and larger cores, as well as fewer proliferating cells and SMC than the Portuguese, conferring the Swedish a more rupture-prone phenotype. Portuguese plaques contained higher ?(13)C and ?(15)N than the Swedish, indicating that Portuguese plaques were more often derived from marine food. Plaque ?(13)C correlated with SMC and proliferating cells, and inversely with lipids, core size, apoptosis. Plaque ?(15)N correlated with SMC and inversely with lipids, core size and apoptosis. This is the first observational study showing that diet is reflected in plaque components associated with its vulnerability. The Portuguese plaques composition is consistent with an increased marine food intake and those plaques are more stable than those from Swedish patients. Marine-derived food is associated with plaque stability. PMID:26490319

  3. Direct association between diet and the stability of human atherosclerotic plaque

    PubMed Central

    Gonçalves, Isabel; Andersson Georgiadou, Elisavet; Mattsson, Sören; Skog, Göran; Pedro, Luís; Fernandes e Fernandes, José; Dias, Nuno; Engström, Gunnar; Nilsson, Jan; Stenström, Kristina

    2015-01-01

    Mediterranean diet has been suggested to explain why coronary heart disease mortality is lower in southern than northern Europe. Dietary habits can be revealed by isotope ratio mass spectrometry (IRMS) measurement of carbon (δ13C) and nitrogen (δ15N) in biological tissues. To study if diet is associated with human plaque stability, atherosclerotic plaques from carotid endarterectomy on 56 patients (21 Portuguese and 35 Swedish) were analysed by IRMS and histology. Plaque components affecting rupture risk were measured. Swedish plaques had more apoptosis, lipids and larger cores, as well as fewer proliferating cells and SMC than the Portuguese, conferring the Swedish a more rupture-prone phenotype. Portuguese plaques contained higher δ13C and δ15N than the Swedish, indicating that Portuguese plaques were more often derived from marine food. Plaque δ13C correlated with SMC and proliferating cells, and inversely with lipids, core size, apoptosis. Plaque δ15N correlated with SMC and inversely with lipids, core size and apoptosis. This is the first observational study showing that diet is reflected in plaque components associated with its vulnerability. The Portuguese plaques composition is consistent with an increased marine food intake and those plaques are more stable than those from Swedish patients. Marine-derived food is associated with plaque stability. PMID:26490319

  4. Atherosclerotic plaque detection by confocal Brillouin and Raman microscopies

    NASA Astrophysics Data System (ADS)

    Meng, Zhaokai; Basagaoglu, Berkay; Yakovlev, Vladislav V.

    2015-02-01

    Atherosclerosis, the development of intraluminal plaque, is a fundamental pathology of cardiovascular system and remains the leading cause of morbidity and mortality worldwide. Biomechanical in nature, plaque rupture occurs when the mechanical properties of the plaque, related to the morphology and viscoelastic properties, are compromised, resulting in intraluminal thrombosis and reduction of coronary blood flow. In this report, we describe the first simultaneous application of confocal Brillouin and Raman microscopies to ex-vivo aortic wall samples. Such a non-invasive, high specific approach allows revealing a direct relationship between the biochemical and mechanical properties of atherosclerotic tissue.

  5. Carotid Atheroma Rupture Observed In Vivo and FSI-Predicted Stress Distribution Based on Pre-rupture Imaging

    PubMed Central

    Rayz, Vitaliy L.; Soares, Bruno; Wintermark, Max; Mofrad, Mohammad R. K.; Saloner, David

    2010-01-01

    Atherosclerosis at the carotid bifurcation is a major risk factor for stroke. As mechanical forces may impact lesion stability, finite element studies have been conducted on models of diseased vessels to elucidate the effects of lesion characteristics on the stresses within plaque materials. It is hoped that patient-specific biomechanical analyses may serve clinically to assess the rupture potential for any particular lesion, allowing better stratification of patients into the most appropriate treatments. Due to a sparsity of in vivo plaque rupture data, the relationship between various mechanical descriptors such as stresses or strains and rupture vulnerability is incompletely known, and the patient-specific utility of biomechanical analyses is unclear. In this article, we present a comparison between carotid atheroma rupture observed in vivo and the plaque stress distribution from fluid–structure interaction analysis based on pre-rupture medical imaging. The effects of image resolution are explored and the calculated stress fields are shown to vary by as much as 50% with sub-pixel geometric uncertainty. Within these bounds, we find a region of pronounced elevation in stress within the fibrous plaque layer of the lesion with a location and extent corresponding to that of the observed site of plaque rupture. PMID:20232151

  6. Plaque neovascularization: defense mechanisms, betrayal, or a war in progress.

    PubMed

    Moreno, Pedro R; Purushothaman, Meeranani; Purushothaman, K-Raman

    2012-04-01

    Angiogenesis is induced from sprouting of preexisting endothelial cells leading to neovascularization. Imbalance in the angiogenic and antiangiogenic mediators triggers angiogenesis, which may be physiological in the normal state or pathological in malignancy and atherosclerosis. Physiologic angiogenesis is instrumental for restoration of vessel wall normoxia and resolution inflammation, leading to atherosclerosis regression. However, pathological angiogenesis enhances disease progression, increasing macrophage infiltration and vessel wall thickness, perpetuating hypoxia and necrosis. In addition, thin-walled fragile neovessels may rupture, leading to intraplaque hemorrhage. Lipid-rich red blood cell membranes and free hemoglobin are detrimental to plaque composition, increasing inflammation, lipid core expansion, and oxidative stress. In addition, associated risk factors that include polymorphysms in the haptoglobin genotype and diabetes mellitus may modulate the features of plaque vulnerability. This review will focus on physiological and pathological angiogenesis in atherosclerosis and summarizes the current status of anti-vascular endothelial growth factor (VEGF) therapy, microvascular rarefaction, and possible statin-mediated effects in atherosclerosis neovascularization. PMID:22548565

  7. Application of infrared fiber optic imaging in atherosclerotic plaques

    NASA Astrophysics Data System (ADS)

    Guo, Bujin; Casscells, S. W.; Bearman, Gregory H.; McNatt, Janice; Naghevi, Morteza; Malik, Basit A.; Gul, Khawar; Willerson, James T.

    1999-07-01

    Rupture of atherosclerotic plaques - the main cause of heart attach and stokes - is not predictable. Hence even treadmill stress tests fail to detect many persons at risk. Fatal plaques are found at autopsies to be associated with active inflammatory cells. Classically, inflammation is detected by its swelling, red color, pain and heat. We have found that heat accurately locates the dangerous plaques that are significantly warmer then atherosclerotic plaques without the same inflammation. In order to develop a non-surgical method of locating these plaques, an IR fiber optic imaging system has been developed in our laboratory to evalute the causes and effect of heat in atherosclerotic plaques. The fiber optical imagin bundle consists of 900 individual As2S3 chalcogenide glass fibers which transmit IR radiation from 0.7 micrometers 7 micrometers with little energy loss. By combining that with a highly sensitive Indium Antimonide IR focal plane array detector, we are able to obtain thermal graphic images in situ. The temperature heterogeneity of atherosclerotic plaques developed in the arteral of the experimental animal models is under study with the new device. The preliminary experimental results from the animal model are encouraging. The potential of using this new technology in diagnostic evaluation of the vulnerable atherosclerotic plaques is considerable.

  8. Complement factor C5a induces atherosclerotic plaque disruptions

    PubMed Central

    Wezel, Anouk; de Vries, Margreet R; Lagraauw, H Maxime; Foks, Amanda C; Kuiper, Johan; Quax, Paul HA; Bot, Ilze

    2014-01-01

    Complement factor C5a and its receptor C5aR are expressed in vulnerable atherosclerotic plaques; however, a causal relation between C5a and plaque rupture has not been established yet. Accelerated atherosclerosis was induced by placing vein grafts in male apoE?/? mice. After 24 days, when advanced plaques had developed, C5a or PBS was applied locally at the lesion site in a pluronic gel. Three days later mice were killed to examine the acute effect of C5a on late stage atherosclerosis. A significant increase in C5aR in the plaque was detectable in mice treated with C5a. Lesion size and plaque morphology did not differ between treatment groups, but interestingly, local treatment with C5a resulted in a striking increase in the amount of plaque disruptions with concomitant intraplaque haemorrhage. To identify the potential underlying mechanisms, smooth muscle cells and endothelial cells were treated in vitro with C5a. Both cell types revealed a marked increase in apoptosis after stimulation with C5a, which may contribute to lesion instability in vivo. Indeed, apoptosis within the plaque was seen to be significantly increased after C5a treatment. We here demonstrate a causal role for C5a in atherosclerotic plaque disruptions, probably by inducing apoptosis. Therefore, intervention in complement factor C5a signalling may be a promising target in the prevention of acute atherosclerotic complications. PMID:25124749

  9. Aterofisiol® in carotid plaque evolution

    PubMed Central

    Amato, Bruno; Compagna, Rita; Amato, Maurizio; Gallelli, Luca; de Franciscis, Stefano; Serra, Raffaele

    2015-01-01

    Background In patients with carotid stenosis, the risk of plaque rupture is related to the composition of the atherosclerotic plaque rather than to its magnitude. In this regard, we evaluated the effects of a supplement, Aterofisiol,® containing omega-3 (EPA [eicosapen acid] DHA [docosahexaenoic acid]), vitamin K2, vitamin B6, vitamin B12, oligomeric proanthocyanidins (OPC) and resveratrol on the composition of atherosclerotic plaque and on neurological symptoms in patients with carotid stenosis undergoing carotid endarterectomy. Methods The study was randomized, prospective, and double-blinded. Eligible patients were of both sexes, with carotid stenosis >70% who underwent endarterectomy. Enrolled patients were randomly allocated to receive either one tablet of acetylsalicylic acid 100 mg (Cardioaspirin®) + one tablet of Aterofisiol every 24 hours or one tablet of Cardioaspirin + one tablet of placebo every 24 hours. Each treatment was started 30 days before the surgery and was stopped 5 days before the surgery. The plaques were removed “en bloc” using standard surgical technique. Results During the study period, 214 patients (135 men and 79 women) were enrolled for intent-to-treat and randomized in two groups: Group A: 107 patients (68 men and 39 women) were treated with Cardioaspirin + Aterofisiol. Group B: 107 patients (67 men and 40 women) were treated with Cardioaspirin + placebo. At the end of the study, 202 patients participated fully (103 patients in Group A and 99 patients in Group B), making up the protocol evaluation population (94.4%). The mean lipid content of removed plaques was significantly lower (P<0.05) in Group A. We recorded a significantly lower incidence of neurological symptoms in Group A in comparison with Group B (P<0.05). Conclusion In the study, Aterofisiol showed to be effective in reducing the amounts of cholesterol and lipids in the plaques and in reducing adverse neurological events in the study group with respect to controls. PMID:26229448

  10. Achilles Tendon Rupture

    PubMed Central

    Wertz, Jess; Galli, Melissa; Borchers, James R.

    2013-01-01

    Context: Achilles tendon (AT) rupture in athletes is increasing in incidence and accounts for one of the most devastating sports injuries because of the threat to alter or end a career. Despite the magnitude of this injury, reliable risk assessment has not been clearly defined, and prevention strategies have been limited. The purpose of this review is to identify potential intrinsic and extrinsic risk factors for AT rupture in aerial and ground athletes stated in the current literature. Evidence Acquisition: A MEDLINE search was conducted on AT rupture, or “injury” and “risk factors” and “athletes” from 1980 to 2011. Emphasis was placed on epidemiology, etiology, and review articles focusing on the risk for lower extremity injury in runners and gymnasts. Thirty articles were reviewed, and 22 were included in this assessment. Results: Aerial and ground athletes share many intrinsic risk factors for AT rupture, including overuse and degeneration of the tendon as well as anatomical variations that mechanically put an athlete at risk. Older athletes, athletes atypical in size for their sport, high tensile loads, leg dominance, and fatigue also may increase risk. Aerial athletes tend to have more extrinsic factors that play a role in this injury due to the varying landing surfaces from heights and technical maneuvers performed at various skill levels. Conclusion: Risk assessment for AT rupture in aerial and ground athletes is multivariable and difficult in terms of developing prevention strategies. Quantitative measures of individual risk factors may help identify major contributors to injury. PMID:24427410

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

    PubMed

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

    2005-04-01

    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 suited for thin-cap fibroatheromas (TCFAs), i.e., plaques with a media region containing a lipid pool covered by a cap. Reconstruction is done by a minimization algorithm that matches the strain image output, calculated with a parametric finite element model (PFEM) representation of a TCFA, to an elastogram by iteratively updating the PFEM geometry and material parameters. These geometry parameters delineate the TCFA media, lipid pool and cap regions by circles. The material parameter for each region is a Young's modulus, EM, EL, and EC, respectively. The method was successfully tested on computer-simulated TCFAs (n = 2), one defined by circles, the other by tracing TCFA histology, and additionally on a physical phantom (n = 1) having a stiff wall (measured EM = 16.8 kPa) with an eccentric soft region (measured EL = 4.2 kPa). Finally, it was applied on human coronary plaques in vitro (n = 1) and in vivo (n = 1). The corresponding simulated and measured elastograms of these plaques showed radial strain values from 0% up to 2% at a pressure differential of 20, 20, 1, 20, and 1 mmHg respectively. The used/reconstructed Young's moduli [kPa] were for the circular plaque EL = 50/66, EM = 1500/1484, EC = 2000/2047, for the traced plaque EL = 25/1, EM = 1000/1148, EC = 1500/1491, for the phantom EL = 4.2/4 kPa, EM = 16.8/16, for the in vitro plaque EL = n.a./29, EM = n.a./647, EC = n.a./1784 kPa and for the in vivo plaque EL = n.a./2, EM = n.a./188, Ec = n.a./188 kPa. PMID:15822809

  12. Intracoronary Imaging in the Detection of Vulnerable Plaques.

    PubMed

    Batty, Jonathan A; Subba, Shristy; Luke, Peter; Gigi, Li Wing Chi; Sinclair, Hannah; Kunadian, Vijay

    2016-03-01

    Coronary artery disease is the result of atherosclerotic changes to the coronary arterial wall, comprising endothelial dysfunction, vascular inflammation and deposition of lipid-rich macrophage foam cells. Certain high-risk atherosclerotic plaques are vulnerable to disruption, leading to rupture, thrombosis and the clinical sequelae of acute coronary syndrome. Though recognised as the gold standard for evaluating the presence, distribution and severity of atherosclerotic lesions, invasive coronary angiography is incapable of identifying non-stenotic, vulnerable plaques that are responsible for adverse cardiovascular events. The recognition of such limitations has impelled the development of intracoronary imaging technologies, including intravascular ultrasound, optical coherence tomography and near-infrared spectroscopy, which enable the detailed evaluation of the coronary wall and atherosclerotic plaques in clinical practice. This review discusses the present status of invasive imaging technologies; summarises up-to-date, evidence-based clinical guidelines; and addresses questions that remain unanswered with regard to the future of intracoronary plaque imaging. PMID:26879196

  13. [Vascular Calcification - Pathological Mechanism and Clinical Application - . The significance of arterial calcification in unstable plaques].

    PubMed

    Inaba, Mayumi; Ueda, Makiko

    2015-05-01

    Plaque rupture or erosion with subsequent thrombus formation is the principal mechanism underlying the sudden onset of acute coronary syndromes. Plaque inflammation and increased oxidative stress play important roles in the pathogenesis of plaque destabilization. Macrophages, T lymphocytes, and neutrophils are the dominant types of inflammatory cells at human coronary unstable plaques, such as ruptured plaques or eroded plaques. Calcification is a common finding in human atherosclerotic lesions, and arterial calcification is generally classified into calcification within an atherosclerotic plaque, and Mönckeberg's medial calcific sclerosis characterized by calcific deposits within the media of small and medium-sized muscular arteries. It has been reported that a spotty pattern of calcification is associated with coronary unstable ruptured plaques in patients with acute myocardial infarction. Patients undergoing hemodialysis (HD) have a high prevalence of arterial calcification and cardiovascular events. We recently demonstrated that plasma oxidized low density lipoprotein (LDL) levels significantly increased after a single HD session. This HD session-related increase in plasma oxidized LDL levels could contribute to the progression and acceleration of atherosclerosis and arterial calcification, leading to the development of cardiovascular events in HD patients. PMID:25926571

  14. Simulation of human atherosclerotic femoral plaque tissue: the influence of plaque material model on numerical results

    PubMed Central

    2015-01-01

    Background Due to the limited number of experimental studies that mechanically characterise human atherosclerotic plaque tissue from the femoral arteries, a recent trend has emerged in current literature whereby one set of material data based on aortic plaque tissue is employed to numerically represent diseased femoral artery tissue. This study aims to generate novel vessel-appropriate material models for femoral plaque tissue and assess the influence of using material models based on experimental data generated from aortic plaque testing to represent diseased femoral arterial tissue. Methods Novel material models based on experimental data generated from testing of atherosclerotic femoral artery tissue are developed and a computational analysis of the revascularisation of a quarter model idealised diseased femoral artery from a 90% diameter stenosis to a 10% diameter stenosis is performed using these novel material models. The simulation is also performed using material models based on experimental data obtained from aortic plaque testing in order to examine the effect of employing vessel appropriate material models versus those currently employed in literature to represent femoral plaque tissue. Results Simulations that employ material models based on atherosclerotic aortic tissue exhibit much higher maximum principal stresses within the plaque than simulations that employ material models based on atherosclerotic femoral tissue. Specifically, employing a material model based on calcified aortic tissue, instead of one based on heavily calcified femoral tissue, to represent diseased femoral arterial vessels results in a 487 fold increase in maximum principal stress within the plaque at a depth of 0.8 mm from the lumen. Conclusions Large differences are induced on numerical results as a consequence of employing material models based on aortic plaque, in place of material models based on femoral plaque, to represent a diseased femoral vessel. Due to these large discrepancies, future studies should seek to employ vessel-appropriate material models to simulate the response of diseased femoral tissue in order to obtain the most accurate numerical results. PMID:25602515

  15. Sintered plaque characteristics

    NASA Technical Reports Server (NTRS)

    Vaidyanathan, H.

    1982-01-01

    The structural transformations occurring during sintering, the fabrication of a slurry produced sintered plaque, are detailed. Degradation of the positive electrode in performance in cycling in a nickel hydrogen battery were traced to the quality of the sintered plaque. Electrode degradation was found to be a limiting factor in the battery cycle life. Details of microstructural characterization and distribution of pores, examination of plastic flow during shrinkage, and observations of the rounding of nickel powder particles during the slurry process are presented.

  16. Atherosclerotic Plaque Destabilization in Mice: A Comparative Study

    PubMed Central

    Hendrikse, Jeffrey; Beckers, Linda; Paulin, Nicole; Van der Heiden, Kim; Braster, Quinte; Drechsler, Maik; Daemen, Mat J.; Lutgens, Esther; Soehnlein, Oliver

    2015-01-01

    Atherosclerosis-associated diseases are the main cause of mortality and morbidity in western societies. The progression of atherosclerosis is a dynamic process evolving from early to advanced lesions that may become rupture-prone vulnerable plaques. Acute coronary syndromes are the clinical manifestation of life-threatening thrombotic events associated with high-risk vulnerable plaques. Hyperlipidemic mouse models have been extensively used in studying the mechanisms controlling initiation and progression of atherosclerosis. However, the understanding of mechanisms leading to atherosclerotic plaque destabilization has been hampered by the lack of proper animal models mimicking this process. Although various mouse models generate atherosclerotic plaques with histological features of human advanced lesions, a consensus model to study atherosclerotic plaque destabilization is still lacking. Hence, we studied the degree and features of plaque vulnerability in different mouse models of atherosclerotic plaque destabilization and find that the model based on the placement of a shear stress modifier in combination with hypercholesterolemia represent with high incidence the most human like lesions compared to the other models. PMID:26492161

  17. Comparison of plaque characteristics in narrowings with ST-elevation myocardial infarction (STEMI), non-STEMI/unstable angina pectoris and stable coronary artery disease (from the ADAPT-DES IVUS Substudy).

    PubMed

    Dong, Liang; Mintz, Gary S; Witzenbichler, Bernhard; Metzger, D Christopher; Rinaldi, Michael J; Duffy, Peter L; Weisz, Giora; Stuckey, Thomas D; Brodie, Bruce R; Yun, Kyeong Ho; Xu, Ke; Kirtane, Ajay J; Stone, Gregg W; Maehara, Akiko

    2015-04-01

    Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents (ADAPT-DES) was a prospective, multicenter registry of 8,582 consecutive stable and unstable patients who underwent percutaneous coronary intervention using a drug-eluting stent. We sought to identify key morphologic features leading to ST-segment elevation myocardial infarction (STEMI) versus non-STEMI (NSTEMI) or unstable angina pectoris (UA) versus stable coronary artery disease (CAD) presentation. In the prespecified grayscale and virtual histology (VH) substudy of ADAPT-DES, preintervention imaging identified 676 patients with a single culprit lesion. The relation between lesion morphology and clinical presentation was compared among patients with (1) STEMI, (2) NSTEMI or UA, and (3) stable CAD. Intravascular ultrasound identified more plaque rupture and VH thin-cap fibroatheroma (TCFA) in STEMI lesions compared with NSTEMI/UA or stable CAD lesions; conversely, fibroatheromas appeared more often calcified with a thick fibrous cap in stable CAD. Minimum lumen cross-sectional area (MLA) was smaller with larger plaque burden and positive remodeling in STEMI lesions. Lesions with plaque rupture versus those without plaque rupture showed higher prevalence of VH-TCFA and larger plaque burden with positive remodeling, especially in patients with STEMI. Multivariate analysis showed that in the lesions with plaque rupture, plaque burden at the MLA site was the only independent predictor for STEMI (cutoff of plaque burden = 85%) and in lesions without plaque rupture, MLA was the only independent predictor for STEMI (cutoff of MLA = 2.3 mm(2)). In conclusion, culprit lesions causing STEMI have smaller lumen areas, greater plaque burden, and more plaque rupture or VH-TCFA compared with NSTEMI/UA or stable CAD; in lesions with plaque rupture, only plaque burden predicted STEMI, and in lesions without plaque rupture, only MLA area predicted STEMI. PMID:25661569

  18. SPECT/CT Imaging of High-Risk Atherosclerotic Plaques using Integrin-Binding RGD Dimer Peptides

    PubMed Central

    Sun Yoo, Jung; Lee, Jonghwan; Ho Jung, Jae; Seok Moon, Byung; Kim, Soonhag; Chul Lee, Byung; Eun Kim, Sang

    2015-01-01

    Vulnerable atherosclerotic plaques with unique biological signatures are responsible for most major cardiovascular events including acute myocardial infarction and stroke. However, current clinical diagnostic approaches for atherosclerosis focus on anatomical measurements such as the degree of luminal stenosis and wall thickness. An abundance of neovessels with elevated expression of integrin αvβ3 is closely associated with an increased risk of plaque rupture. Herein we evaluated the potential of an αvβ3 integrin-targeting radiotracer, 99mTc-IDA-D-[c(RGDfK)]2, for SPECT/CT imaging of high-risk plaque in murine atherosclerosis models. In vivo uptake of 99mTc-IDA-D-[c(RGDfK)]2 was significantly higher in atherosclerotic aortas than in relatively normal aortas. Comparison with the negative-control peptide, 99mTc-IDA-D-[c(RADfK)]2, proved specific binding of 99mTc-IDA-D-[c(RGDfK)]2 for plaque lesions in in vivo SPECT/CT and ex vivo autoradiographic imaging. Histopathological characterization revealed that a prominent SPECT signal of 99mTc-IDA-D-[c(RGDfK)]2 corresponded to the presence of high-risk plaques with a large necrotic core, a thin fibrous cap, and vibrant neoangiogenic events. Notably, the RGD dimer based 99mTc-IDA-D-[c(RGDfK)]2 showed better imaging performance in comparison with the common monomeric RGD peptide probe 123I-c(RGDyV) and fluorescence tissue assay corroborated this. Our preclinical data demonstrated that 99mTc-IDA-D-[c(RGDfK)]2 SPECT/CT is a sensitive tool to noninvasively gauge atherosclerosis beyond vascular anatomy by assessing culprit plaque neovascularization. PMID:26123253

  19. Markers of Inflammation Associated with Plaque Progression and Instability in Patients with Carotid Atherosclerosis

    PubMed Central

    Ammirati, Enrico; Moroni, Francesco; Norata, Giuseppe Danilo; Magnoni, Marco; Camici, Paolo G.

    2015-01-01

    Atherosclerosis is the focal expression of a systemic disease affecting medium- and large-sized arteries, in which traditional cardiovascular risk factor and immune factors play a key role. It is well accepted that circulating biomarkers, including C-reactive protein and interleukin-6, reliably predict major cardiovascular events, including myocardial infarction or death. However, the relevance of biomarkers of systemic inflammation to atherosclerosis progression in the carotid artery is less established. The large majority of clinical studies focused on the association between biomarkers and subclinical atherosclerosis, that is, carotid intima-media thickening (cIMT), which represents an earlier stage of the disease. The aim of this work is to review inflammatory biomarkers that were associated with a higher atherosclerotic burden, a faster disease progression, and features of plaque instability, such as inflammation or neovascularization, in patients with carotid atherosclerotic plaque, which represents an advanced stage of disease compared with cIMT. The association of biomarkers with the occurrence of cerebrovascular events, secondary to carotid plaque rupture, will also be presented. Currently, the degree of carotid artery stenosis is used to predict the risk of future cerebrovascular events in patients affected by carotid atherosclerosis. However, this strategy appears suboptimal. The identification of suitable biomarkers could provide a useful adjunctive criterion to ensure better risk stratification and optimize management. PMID:25960621

  20. Differential Inhibition of Human Atherosclerotic Plaque–Induced Platelet Activation by Dimeric GPVI-Fc and Anti-GPVI Antibodies

    PubMed Central

    Jamasbi, Janina; Megens, Remco T.A.; Bianchini, Mariaelvy; Münch, Götz; Ungerer, Martin; Faussner, Alexander; Sherman, Shachar; Walker, Adam; Goyal, Pankaj; Jung, Stephanie; Brandl, Richard; Weber, Christian; Lorenz, Reinhard; Farndale, Richard; Elia, Natalie; Siess, Wolfgang

    2015-01-01

    Background Glycoprotein VI (GPVI) is the essential platelet collagen receptor in atherothrombosis, but its inhibition causes only a mild bleeding tendency. Thus, targeting this receptor has selective antithrombotic potential. Objectives This study sought to compare compounds interfering with platelet GPVI–atherosclerotic plaque interaction to improve current antiatherothrombotic therapy. Methods Human atherosclerotic plaque–induced platelet aggregation was measured in anticoagulated blood under static and arterial flow conditions (550/s, 1,100/s, and 1,500/s). Inhibition by dimeric GPVI fragment crystallizable region of IgG (Fc) masking GPVI binding sites on collagen was compared with that of 3 anti-GPVI antibodies: BLO8-1, a human domain antibody; 5C4, a fragment antigen-binding (Fab fragment) of monoclonal rat immunoglobulin G; and m-Fab-F, a human recombinant sFab against GPVI dimers. Results GPVI-Fc reduced plaque-triggered platelet aggregation in static blood by 51%, BLO8-1 by 88%, and 5C4 by 93%. Under arterial flow conditions, BLO8-1 and 5C4 almost completely inhibited platelet aggregation while preserving platelet adhesion on plaque. Inhibition by GPVI-Fc, even at high concentrations, was less marked but increased with shear rate. Advanced optical imaging revealed rapid persistent GPVI-Fc binding to collagen under low and high shear flow, upstream and downstream of plaque fragments. At low shear particularly, platelets adhered in plaque flow niches to GPVI-Fc–free segments of collagen fibers and recruited other platelets onto aggregates via ADP and TxA2 release. Conclusions Anti-GPVI antibodies inhibit atherosclerotic plaque-induced platelet aggregation under static and flow conditions more effectively than GPVI-Fc. However, potent platelet inhibition by GPVI-Fc at a higher shear rate (1,500/s) suggests localized antithrombotic efficacy at denuded or fissured stenotic high-risk lesions without systemic bleeding. The compound-specific differences have relevance for clinical trials targeting GPVI-collagen interaction combined with established antiplatelet therapies in patients with spontaneous plaque rupture or intervention-associated plaque injury. PMID:26046734

  1. Atherosclerotic plaque uptake of a novel integrin tracer 18F-Flotegatide in a mouse model of atherosclerosis

    PubMed Central

    Su, Helen; Gorodny, Natalia; Gomez, Luis Felipe; Gangadharmath, Umesh B.; Mu, Fanrong; Chen, Gang; Walsh, Joseph C.; Szardenings, Katrin; Berman, Daniel S; Kolb, Hartmuth C.; Tamarappoo, Balaji K.

    2015-01-01

    Rupture of unstable atherosclerotic plaque is the primary event leading to stroke and myocardial infarction. Plaque vulnerability may be induced by macrophage infiltration, neovessel formation and intraplaque instability. A tracer that selectively binds to macrophages and neovascular endothelium may identify rupture prone plaque. The 18F-labeled “R-G-D” containing tripeptide (Flotegatide) is a click chemistry derived radiotracer that binds to integrin ?v?3, a protein present in vulnerable plaque. We now demonstrate that Flotegatide preferentially binds to aortic plaque in an ApoE knock out mouse model of atherosclerosis. The tracer's uptake is strongly associated with presence of histologic markers for macrophage infiltration and integrin expression. There is a weaker but detectable association between Flotegatide uptake and presence of an immunohistochemical marker for neovascularization. We hypothesize that Flotegatide may be a useful tracer for visualization of inflamed plaque in clinical subjects. PMID:24627345

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

    PubMed

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

    2013-01-01

    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

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

    PubMed Central

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

    2012-01-01

    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

  4. Quantification of cholesteryl esters in human and rabbit atherosclerotic plaques by magic-angle spinning (13)C-NMR.

    PubMed

    Peng, S; Guo, W; Morrisett, J D; Johnstone, M T; Hamilton, J A

    2000-12-01

    Accumulation of cholesteryl esters (CEs) is a key event in the formation of atherosclerotic plaques. More recent work suggests a role for CEs in plaque rupture leading to thrombosis, which can result in an acute event such as myocardial infarction or stroke. In this study, we present nuclear magnetic resonance (NMR) protocols for quantification of CEs in plaques in situ. Total CEs quantified by (13)C magic-angle spinning (MAS) NMR in excised plaques from human carotid arteries and rabbit aortic arteries were in good agreement with the amounts determined by subsequent standard chemical assays. The latter analysis is disadvantageous because it requires that plaque lipids be extracted from the tissue, resulting in the loss of all phase information of CEs as well as other major plaque components. With our MAS-NMR protocol, the plaque components are preserved in their native phases. Combining MAS and off-MAS NMR, we were able to quantitatively distinguish isotropic (liquid) CEs from anisotropic (liquid-crystalline) CEs in plaque tissues. In a recent study, we applied a different (13)C MAS-NMR protocol to quantify crystalline cholesterol monohydrate in plaques. Together, these 2 studies describe a new, noninvasive MAS-NMR strategy for the identification and quantification of the major lipid components in plaques in situ. This approach will be useful for investigation of the relationship between plaque rupture and specific lipids in their biologically relevant phases. PMID:11116072

  5. The microscopic network structure of mussel (Mytilus) adhesive plaques.

    PubMed

    Filippidi, Emmanouela; DeMartini, Daniel G; Malo de Molina, Paula; Danner, Eric W; Kim, Juntae; Helgeson, Matthew E; Waite, J Herbert; Valentine, Megan T

    2015-12-01

    Marine mussels of the genus Mytilus live in the hostile intertidal zone, attached to rocks, bio-fouled surfaces and each other via collagen-rich threads ending in adhesive pads, the plaques. Plaques adhere in salty, alkaline seawater, withstanding waves and tidal currents. Each plaque requires a force of several newtons to detach. Although the molecular composition of the plaques has been well studied, a complete understanding of supra-molecular plaque architecture and its role in maintaining adhesive strength remains elusive. Here, electron microscopy and neutron scattering studies of plaques harvested from Mytilus californianus and Mytilus galloprovincialis reveal a complex network structure reminiscent of structural foams. Two characteristic length scales are observed characterizing a dense meshwork (approx. 100 nm) with large interpenetrating pores (approx. 1 µm). The network withstands chemical denaturation, indicating significant cross-linking. Plaques formed at lower temperatures have finer network struts, from which we hypothesize a kinetically controlled formation mechanism. When mussels are induced to create plaques, the resulting structure lacks a well-defined network architecture, showcasing the importance of processing over self-assembly. Together, these new data provide essential insight into plaque structure and formation and set the foundation to understand the role of plaque structure in stress distribution and toughening in natural and biomimetic materials. PMID:26631333

  6. 9. VIEW OF BRIDGE PLAQUE. PLAQUE IS LOCATED ON EASTERN ...

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

    9. VIEW OF BRIDGE PLAQUE. PLAQUE IS LOCATED ON EASTERN PARAPET ABOVE PIER. - Core Creek County Bridge, Spanning Core Creek, approximately 1 mile South of State Route 332 (Newtown Bypass), Newtown, Bucks County, PA

  7. A computational fluid-structure interaction model for plaque vulnerability assessment in atherosclerotic human coronary arteries

    NASA Astrophysics Data System (ADS)

    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza; Haghpanahi, Mohammad

    2014-04-01

    Coronary artery disease is responsible for a third of global deaths worldwide. Computational simulations of blood flow can be used to understand the interactions of artery/plaque and blood in coronary artery disease and to better predict the rupture of atherosclerotic plaques. So far, the mechanical properties of animals' coronary artery have been mostly used for hemodynamic simulation of atherosclerotic arteries. The mechanical properties of animals' coronary arteries are often not accurate enough and can be only used for an approximate estimation and comparative assessment of the cognate parameters in human. In this study, a three-dimensional (3D) computational fluid-structure interactions model with three different plaque types is presented to perform a more accurate plaque vulnerability assessment for human atherosclerotic plaques. The coronary arteries of twenty-two male individuals were removed during autopsy and subjected to uniaxial tensile loading. The hyperelastic material coefficients of coronary arteries were calculated and implemented to the computational model. The fully coupled fluid and structure models were solved using the explicit dynamics finite element code LS-DYNA. The normal and shear stresses induced within the plaques were significantly affected by different plaque types. The highest von Mises (153 KPa) and shear (57 KPa) stresses were observed for hypocellular plaques, while the lowest von Mises (70 KPa) and shear (39 KPa) stresses were observed on the stiffer calcified plaques. The results suggest that the risk of plaque rupture due to blood flow is lower for cellular and hypocellular plaques, while higher for calcified plaques with low fracture stresses.

  8. Identifying Vulnerable Atherosclerotic Plaque in Rabbits Using DMSA-USPIO Enhanced Magnetic Resonance Imaging to Investigate the Effect of Atorvastatin

    PubMed Central

    Li, Dongye; Wu, Weiheng; Gong, Lei; Li, Yong; Zhang, Qingdui; Zhang, Tao; Zhang, Chao; Zhang, Yu

    2015-01-01

    Background Rupture of an atherosclerotic plaque is the primary cause of acute cardiovascular and cerebrovascular syndromes. Early and non-invasive detection of vulnerable atherosclerotic plaques (VP) would be significant in preventing some aspects of these syndromes. As a new contrast agent, dimercaptosuccinic acid (DMSA) modified ultra-small super paramagnetic iron oxide (USPIO) was synthesized and used to identify VP and rupture plaque by magnetic resonance imaging (MRI). Methods Atherosclerosis was induced in male New Zealand White rabbits by feeding a high cholesterol diet (n = 30). Group A with atherosclerosis plaque (n = 10) were controls. VP was established in groups B (n = 10) and C (n = 10) using balloon-induced endothelial injury of the abdominal aorta. Adenovirus-carrying p53 genes were injected into the aortic segments rich in plaques after 8 weeks. Group C was treated with atorvastatin for 8 weeks. Sixteen weeks later, all rabbits underwent pharmacological triggering, and imaging were taken daily for 5 d after DMSA-USPIO infusion. At the first day and before being killed, serum MMP-9, sCD40L, and other lipid indicators were measured. Results DMSA-USPIO particles accumulated in VP and rupture plaques. Rupture plaques appeared as areas of hyper-intensity on DMSA-USPIO enhanced MRI, especially T2*-weighted sequences, with a signal strength peaking at 96 h. The group given atorvastatin showed few DMSA-USPIO particles and had lower levels of serum indicators. MMP-9 and sCD40L levels in group B were significantly higher than in the other 2 groups (P <0.05). Conclusion After successfully establishing a VP model in rabbits, DMSA-USPIO was used to enhance MRI for clear identification of plaque inflammation and rupture. Rupture plaques were detectable in this way probably due to an activating inflammatory process. Atorvastatin reduced the inflammatory response and stabilizing VP possibly by decreasing MMP-9 and sCD40L levels. PMID:25973795

  9. Mechanical stresses in carotid plaques using MRI-based fluid-structure interaction models.

    PubMed

    Kock, Samuel A; Nygaard, Jens V; Eldrup, Nikolaj; Fründ, Ernst-Torben; Klaerke, Anette; Paaske, William P; Falk, Erling; Yong Kim, W

    2008-01-01

    Risk assessment in patients with carotid atherosclerosis relies on the degree of luminal stenosis. Incorporating morphological information on plaque composition obtained noninvasively through the use of magnetic resonance imaging (MRI) could include other variables besides the degree of stenosis into carotid plaque risk assessment. Knowledge of the morphologic composition of the plaque allows determination of mechanic stresses exerted on the protective fibrous cap, which may be of importance in the assessment of plaque vulnerability. Based on image processing of transverse MRI scans, longitudinal 2D fluid-structure interaction (FSI) simulations of carotid atherosclerotic plaques were performed facilitating in-vivo estimation of longitudinal internal fibrous cap stresses. The FSI simulation combined finite element analysis (FEA) with computational fluid dynamics (CFD) simulations of blood-flow variables. Preliminary results from two symptomatic patients revealed longitudinal stress levels (max. 254.1 and 143.2 kPa) approaching established criteria for plaque rupture at known predilection sites of plaque rupture. Determination of longitudinal fibrous cap stresses may prove useful in assessing plaque vulnerability and improve risk stratification in patients with carotid atherosclerosis. PMID:18485351

  10. Aetiology of pleural plaques

    PubMed Central

    Rous, V.; Studeny, J.

    1970-01-01

    Pleural plaques were found in 644 (6·6%) of 9,760 photofluorograms taken in 1965 in a region of Pelhřimov district; the incidence was highest in the age group 66-70 years. The advanced age of those affected may be explained by the greater frequency of the causative agent in the past. The disorder was known in Pelhřimov district as early as 1930; it was then thought to be posttuberculous. The past history of the cases was uninformative; as a rule, the only common previous disease was pleurisy with effusion, occurring in 9·7%. The general condition of those affected was excellent; only 8% were aware of the fact that pleural lesions were present. The disorder was found mainly in farmers, familial incidence was common, and if two generations of one family suffered from the condition, the older generation was affected in 100%. Pleural plaques consist morphologically of limited areas of hyalinized collagenous connective tissue with calcium salt deposits. Tubercle bacilli could not be cultivated from the lesions. Mineralological analysis showed no evidence of silicates in the pleural plaques and a normal content in the lungs. The aetiological factor responsible for the development of pleural plaques in Pelhřimov district is not known, but asbestos cannot be implicated. The unknown noxious agent is carried to the pleura by the lymph and blood stream. Pleural plaques are an endemic disorder. The traditional view that lesions are post-tuberculous appears, in the region submitted to this study, to be a possible explanation. Images PMID:5465601

  11. Effect of calcification on the mechanical stability of plaque based on a three-dimensional carotid bifurcation model

    PubMed Central

    2012-01-01

    Background This study characterizes the distribution and components of plaque structure by presenting a three-dimensional blood-vessel modelling with the aim of determining mechanical properties due to the effect of lipid core and calcification within a plaque. Numerical simulation has been used to answer how cap thickness and calcium distribution in lipids influence the biomechanical stress on the plaque. Method Modelling atherosclerotic plaque based on structural analysis confirms the rationale for plaque mechanical examination and the feasibility of our simulation model. Meaningful validation of predictions from modelled atherosclerotic plaque model typically requires examination of bona fide atherosclerotic lesions. To analyze a more accurate plaque rupture, fluid-structure interaction is applied to three-dimensional blood-vessel carotid bifurcation modelling. A patient-specific pressure variation is applied onto the plaque to influence its vulnerability. Results Modelling of the human atherosclerotic artery with varying degrees of lipid core elasticity, fibrous cap thickness and calcification gap, which is defined as the distance between the fibrous cap and calcification agglomerate, form the basis of our rupture analysis. Finite element analysis shows that the calcification gap should be conservatively smaller than its threshold to maintain plaque stability. The results add new mechanistic insights and methodologically sound data to investigate plaque rupture mechanics. Conclusion Structural analysis using a three-dimensional calcified model represents a more realistic simulation of late-stage atherosclerotic plaque. We also demonstrate that increases of calcium content that is coupled with a decrease in lipid core volume can stabilize plaque structurally. PMID:22336469

  12. Identifying Vulnerable Plaques with Acoustic Radiation Force Impulse Imaging

    NASA Astrophysics Data System (ADS)

    Doherty, Joshua Ryan

    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.

  13. How Does Calcification Influence Plaque Vulnerability? Insights from Fatigue Analysis

    PubMed Central

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

    2014-01-01

    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

  14. Characterising human atherosclerotic carotid plaque tissue composition and morphology using combined spectroscopic and imaging modalities

    PubMed Central

    2015-01-01

    Calcification is a marked pathological component in carotid artery plaque. Studies have suggested that calcification may induce regions of high stress concentrations therefore increasing the potential for rupture. However, the mechanical behaviour of the plaque under the influence of calcification is not fully understood. A method of accurately characterising the calcification coupled with the associated mechanical plaque properties is needed to better understand the impact of calcification on the mechanical behaviour of the plaque during minimally invasive treatments. This study proposes a comparison of biochemical and structural characterisation methods of the calcification in carotid plaque specimens to identify plaque mechanical behaviour. Biochemical analysis, by Fourier Transform Infrared (FTIR) spectroscopy, was used to identify the key components, including calcification, in each plaque sample. However, FTIR has a finite penetration depth which may limit the accuracy of the calcification measurement. Therefore, this FTIR analysis was coupled with the identification of the calcification inclusions located internally in the plaque specimen using micro x-ray computed tomography (?X-CT) which measures the calcification volume fraction (CVF) to total tissue content. The tissue characterisation processes were then applied to the mechanical material plaque properties acquired from experimental circumferential loading of human carotid plaque specimen for comparison of the methods. FTIR characterised the degree of plaque progression by identifying the functional groups associated with lipid, collagen and calcification in each specimen. This identified a negative relationship between stiffness and 'lipid to collagen' and 'calcification to collagen' ratios. However, ?X-CT results suggest that CVF measurements relate to overall mechanical stiffness, while peak circumferential strength values may be dependent on specific calcification geometries. This study demonstrates the need to fully characterise the calcification structure of the plaque tissue and that a combination of FTIR and ?X-CT provides the necessary information to fully understand the mechanical behaviour of the plaque tissue. PMID:25602176

  15. La pelade par plaques

    PubMed Central

    Spano, Frank; Donovan, Jeff C.

    2015-01-01

    Résumé Objectif Présenter aux médecins de famille des renseignements de base pour faire comprendre les schémas thérapeutiques et les résultats des traitements pour la pelade par plaques, de même que les aider à identifier les patients pour qui une demande de consultation en dermatologie pourrait s’imposer. Sources des données Une recension a été effectuée dans PubMed pour trouver des articles pertinents concernant le traitement de la pelade par plaques. Message principal La pelade par plaques est une forme auto-immune de perte pileuse qui touche à la fois les enfants et les adultes. Même s’il n’y a pas de mortalité associée à la maladie, la morbidité découlant des effets psychologiques de la perte des cheveux peut être dévastatrice. Lorsque la pelade par plaques et le sous-type de la maladie sont identifiés, un schéma thérapeutique approprié peut être amorcé pour aider à arrêter la chute des cheveux et possiblement faire commencer la repousse. Les traitements de première intention sont la triamcinolone intralésionnelle avec des corticostéroïdes topiques ou du minoxidil ou les 2. Les médecins de famille peuvent prescrire ces traitements en toute sécurité et amorcer ces thérapies. Les cas plus avancés ou réfractaires pourraient avoir besoin de diphénylcyclopropénone topique ou d’anthraline topique. On peut traiter la perte de cils avec des analogues de la prostaglandine. Les personnes ayant subi une perte de cheveux abondante peuvent recourir à des options de camouflage ou à des prothèses capillaires. Il est important de surveiller les troubles psychiatriques en raison des effets psychologiques profonds de la perte de cheveux. Conclusion Les médecins de famille verront de nombreux patients qui perdent leurs cheveux. La reconnaissance de la pelade par plaques et la compréhension du processus pathologique sous-jacent permettent d’amorcer un schéma thérapeutique approprié. Les cas plus graves ou réfractaires doivent être identifiés pour qu’une demande de consultation en dermatologie soit demandée au besoin.

  16. La pelade par plaques

    PubMed Central

    Spano, Frank; Donovan, Jeff C.

    2015-01-01

    Résumé Objectif Présenter aux médecins de famille des renseignements de base pour faire comprendre l’épidémiologie, la pathogenèse, l’histologie et l’approche clinique au diagnostic de la pelade par plaques. Sources des données Une recension a été effectuée dans PubMed pour trouver des articles pertinents concernant la pathogenèse, le diagnostic et le pronostic de la pelade par plaques. Message principal La pelade par plaques est une forme de perte pileuse auto-immune dont la prévalence durant une vie est d’environ 2 %. Des antécédents personnels ou familiaux de troubles auto-immuns concomitants, comme le vitiligo ou une maladie de la thyroïde, peuvent être observés dans un petit sous-groupe de patients. Le diagnostic peut souvent être posé de manière clinique en se fondant sur la perte de cheveux non cicatricielle et circulaire caractéristique, accompagnée de cheveux en « point d’exclamation » en périphérie chez ceux dont le problème en est aux premiers stades. Le diagnostic des cas plus complexes ou des présentations inhabituelles peut être facilité par une biopsie et un examen histologique. Le pronostic varie largement et de mauvais résultats sont associés à une apparition à un âge précoce, une perte importante, la variante ophiasis, des changements aux ongles, des antécédents familiaux ou des troubles auto-immuns concomitants. Conclusion La pelade par plaques est une forme auto-immune de perte de cheveux périodiquement observée en soins primaires. Les médecins de famille sont bien placés pour identifier la pelade par plaques, déterminer la gravité de la maladie et poser le diagnostic différentiel approprié. De plus, ils sont en mesure de renseigner leurs patients à propos de l’évolution clinique de la maladie ainsi que du pronostic général selon le sous-type de patients.

  17. Three-dimensional dosimetry imaging of I-125 plaque for eye cancer treatment

    NASA Astrophysics Data System (ADS)

    Weaver, M.; Green, J.; Petasecca, M.; Lerch, M. L. F.; Cutajar, D.; Franklin, D.; Jakubek, J.; Carolan, M. G.; Conway, M.; Pospisil, S.; Kron, T.; Metcalfe, P.; Zaider, M.; Rosenfeld, A. B.

    2011-05-01

    Treatment of ocular cancers using eye plaque brachytherapy is now an established medical procedure. However, current QA for these eye plaques is quite rudimentary, limiting the opportunities for precise pre-tumour plaque customisation. This paper proposes and experimentally validates a new technique for imaging of eye plaque dose distributions using a high-resolution pixelated silicon detector. Results are presented demonstrating the 2D and 3D isodose surfaces produced using experimental data collected using this method.

  18. Cobalt60 plaques in recurrent retinoblastoma

    SciTech Connect

    Fass, D.; McCormick, B.; Abramson, D.; Ellsworth, R. )

    1991-08-01

    Cobalt60 plaque irradiation is one treatment option for patients with recurrent retinoblastoma following conventional external beam irradiation (ERT). Tumorocidal doses can be delivered without excessive risk of normal tissue injury. In patients not considered candidates for xenon arc or cryotherapy, 60Co is an alternative to enucleation. Between 1968 and 1987, 85 patients were treated with 60Co plaques, 72 of whom had failed prior ERT. Age at diagnosis ranged from 1 week to 4 years. There are 37 males and 35 females. Seventy-one patients had bilateral disease and one had unilateral. Three patients had both eyes plaqued. Prior ERT ranged from 30 to 70 Gy (mean 4200 Gy). Time from initial therapy to failure ranged from 13 to 60 months. Cobalt plaques of 10 mm, 15 mm, or 10 {times} 15 mm were used depending on tumor size and location. Dose prescribed to the apex of the tumor ranged from 30 to 50 Gy (median 40 Gy) given over 3 to 8 days. Twelve patients had two plaque applications; three patients had three plaque applications. All patients were followed with routine ophthalmoscopic examinations. Follow-up ranged from 2 to 22 years (mean 8.7). Seven patients died of metastatic disease; 10 patients developed non-ocular second tumors. Thirty patients required enucleation. Twenty-two patients had clear tumor progression, two patients had radiation complications, and six patients had a combination of tumor growth and complications. Cobalt60 can salvage eyes in retinoblastoma patients failing ERT. Currently, the authors are using I125 in an attempt to spare normal ocular tissue and reduce subsequent complications.

  19. The effects of plaque morphology and material properties on peak cap stress in human coronary arteries.

    PubMed

    Akyildiz, Ali C; Speelman, Lambert; Nieuwstadt, Harm A; van Brummelen, Harald; Virmani, Renu; van der Lugt, Aad; van der Steen, Anton F W; Wentzel, Jolanda J; Gijsen, Frank J H

    2016-05-01

    Heart attacks are often caused by rupture of caps of atherosclerotic plaques in coronary arteries. Cap rupture occurs when cap stress exceeds cap strength. We investigated the effects of plaque morphology and material properties on cap stress. Histological data from 77 coronary lesions were obtained and segmented. In these patient-specific cross sections, peak cap stresses were computed by using finite element analyses. The finite element analyses were 2D, assumed isotropic material behavior, and ignored residual stresses. To represent the wide spread in material properties, we applied soft and stiff material models for the intima. Measures of geometric plaque features for all lesions were determined and their relations to peak cap stress were examined using regression analyses. Patient-specific geometrical plaque features greatly influence peak cap stresses. Especially, local irregularities in lumen and necrotic core shape as well as a thin intima layer near the shoulder of the plaque induce local stress maxima. For stiff models, cap stress increased with decreasing cap thickness and increasing lumen radius (R = 0.79). For soft models, this relationship changed: increasing lumen radius and increasing lumen curvature were associated with increased cap stress (R = 0.66). The results of this study imply that not only accurate assessment of plaque geometry, but also of intima properties is essential for cap stress analyses in atherosclerotic plaques in human coronary arteries. PMID:26237279

  20. Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque.

    PubMed

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

    2011-01-01

    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. PMID:21280896

  1. Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque

    PubMed Central

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

    2011-01-01

    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. PMID:21280896

  2. Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    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.

  3. Bi-modal imaging of atherosclerotic plaques: Automated method for co-registration between fluorescence lifetime imaging and intravascular ultrasound data

    NASA Astrophysics Data System (ADS)

    Gorpas, Dimitris; Fatakdawala, Hussain; Bec, Julien; Ma, Dinglong; Yankelevich, Diego R.; Bishop, John W.; Qi, Jinyi; Marcu, Laura

    2014-03-01

    The risk of atherosclerosis plaque rupture cannot be assessed by the current imaging systems and thus new multi-modal technologies are under investigation. This includes combining a new fluorescence lifetime imaging (FLIm) technique, which is sensitive to plaque biochemical features, with conventional intravascular ultrasound (IVUS), which provides information on plaque morphology. In this study we present an automated method allowing for the co-registration of imaging data acquired based on these two techniques. Intraluminal studies were conducted in ex-vivo segments of human coronaries with a multimodal catheter integrating a commercial IVUS (40 MHz) and a rotational side-viewing fiber based multispectral FLIm system (355 nm excitation, 390+/-20, 452+/-22 and 542+/-25 nm acquisition wavelengths). The proposed method relies on the lumen/intima boundary extraction from the IVUS polar images. Image restoration is applied for the noise reduction and edge enhancement, while gray-scale peak tracing over the A-lines of the IVUS polar images is applied for the lumen boundary extraction. The detection of the guide-wire artifact is used for the angular registration between FLIm and IVUS data, after which the lifetime values can be mapped onto the segmented lumen/intima interface. The segmentation accuracy has been assessed against manual tracings, providing 0.120+/-0.054 mm mean Hausdorff distance. This method makes the bi-modal FLIm and IVUS approach feasible for comprehensive intravascular diagnostic by providing co-registered biochemical and morphological information about atherosclerotic plaques.

  4. F-18 Fluoride Positron Emission Tomography-Computed Tomography for Detecting Atherosclerotic Plaques.

    PubMed

    Kang, Won Jun

    2015-01-01

    A large number of major cardiovascular events occur in patients due to minimal or some lumen narrowing of the coronary artery. Recent biological studies have shown that the biological composition or vulnerability of the plaque is more critical for plaque rupture compared to the degree of stenosis. To overcome the limitations of anatomical images, molecular imaging techniques have been suggested as promising imaging tools in various fields. F-18 fluorodeoxyglucose (FDG), which is widely used in the field of oncology, is an example of molecular probes used in atherosclerotic plaque evaluation. FDG is a marker of plaque macrophage glucose utilization and inflammation, which is a prominent characteristic of vulnerable plaque. Recently, F-18 fluoride has been used to visualize vulnerable plaque in clinical studies. F-18 fluoride accumulates in regions of active microcalcification, which is normally observed during the early stages of plaque formation. More studies are warranted on the accumulation of F-18 fluoride and plaque formation/vulnerability; however, due to high specific accumulation, low background activity, and easy accessibility, F-18 fluoride is emerging as a promising non-invasive imaging probe to detect vulnerable plaque. PMID:26576114

  5. F-18 Fluoride Positron Emission Tomography-Computed Tomography for Detecting Atherosclerotic Plaques

    PubMed Central

    2015-01-01

    A large number of major cardiovascular events occur in patients due to minimal or some lumen narrowing of the coronary artery. Recent biological studies have shown that the biological composition or vulnerability of the plaque is more critical for plaque rupture compared to the degree of stenosis. To overcome the limitations of anatomical images, molecular imaging techniques have been suggested as promising imaging tools in various fields. F-18 fluorodeoxyglucose (FDG), which is widely used in the field of oncology, is an example of molecular probes used in atherosclerotic plaque evaluation. FDG is a marker of plaque macrophage glucose utilization and inflammation, which is a prominent characteristic of vulnerable plaque. Recently, F-18 fluoride has been used to visualize vulnerable plaque in clinical studies. F-18 fluoride accumulates in regions of active microcalcification, which is normally observed during the early stages of plaque formation. More studies are warranted on the accumulation of F-18 fluoride and plaque formation/vulnerability; however, due to high specific accumulation, low background activity, and easy accessibility, F-18 fluoride is emerging as a promising non-invasive imaging probe to detect vulnerable plaque. PMID:26576114

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

    PubMed Central

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

    2014-01-01

    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

  7. Non-pulsed electrochemical impregnation of flexible metallic battery plaques

    DOEpatents

    Maskalick, Nicholas J. (Pittsburgh, PA)

    1982-01-01

    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.

  8. Macrophage-targeted photodynamic detection of vulnerable atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

    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.

    2003-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza

    2014-07-01

    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.

  10. Chronic intermittent mental stress promotes atherosclerotic plaque vulnerability, myocardial infarction and sudden death in mice.

    PubMed

    Roth, Lynn; Rombouts, Miche; Schrijvers, Dorien M; Lemmens, Katrien; De Keulenaer, Gilles W; Martinet, Wim; De Meyer, Guido R Y

    2015-09-01

    Vulnerable atherosclerotic plaques are prone to plaque rupture leading to acute cardiovascular syndromes and death. Elucidating the risk of plaque rupture is important to define better therapeutic or preventive strategies. In the present study, we investigated the effect of chronic intermittent mental stress on atherosclerotic plaque stability and cardiovascular mortality in apolipoprotein E-deficient (ApoE(-/-)) mice with a heterozygous mutation in the fibrillin-1 gene (Fbn1(C1039G+/)(-)). This mouse model displays exacerbated atherosclerosis with spontaneous plaque ruptures, myocardial infarction and sudden death, when fed a Western-type diet (WD). Female ApoE(-/-)Fbn1(C1039G+/-) mice were fed a WD for up to 25 weeks. After 10 weeks WD, mice were divided in a control (n = 27) and mental stress (n = 29) group. The chronic intermittent mental stress protocol consisted of 3 triggers: water avoidance, damp bedding and restraint stress, in a randomly assigned order lasting 6 h every weekday for 15 weeks. Chronic intermittent mental stress resulted in a significant increase in the amount of macrophages in atherosclerotic plaques of the proximal ascending aorta, whereas type I collagen and fibrous cap thickness were decreased. The coronary arteries of mental stress-treated mice showed larger plaques, more stenosis, and an increased degree of perivascular fibrosis. Moreover, myocardial infarctions occurred more frequently in the mental stress group. As compared to the control group, the survival of stressed ApoE(-/-)Fbn1(C1039G+/-) mice decreased from 67% to 52% at 25 weeks WD, presumably due to myocardial infarctions. In conclusion, chronic intermittent mental stress promotes plaque instability, myocardial infarctions, and mortality of ApoE(-/-)Fbn1(C1039G+/-) mice. PMID:26233915

  11. [Achilles tendon rupture].

    PubMed

    Thermann, H; Hüfner, T; Tscherne, H

    2000-03-01

    The treatment of acute of Achilles tendon rupture experienced a dynamic development in the last ten years. Decisive for this development was the application of MRI and above all the ultrasonography in the diagnostics of the pathological changes and injuries of tendons. The question of rupture morphology as well as different courses of healing could be now evaluated objectively. These advances led consequently to new modalities in treatment concepts and rehabilitation protocols. The decisive input for improvements of the outcome results and particularly the shortening of the rehabilitation period came with introduction of the early functional treatment in contrast to immobilizing plaster treatment. In a prospective randomized study (1987-1989) at the Trauma Dept. of the Hannover Medical School could show no statistical differences comparing functional non-operative with functional operative therapy with a special therapy boot (Variostabil/Adidas). The crucial criteria for therapy selection results from the sonographically measured position of the tendon stumps in plantar flexion (20 degrees). With complete adaptation of the tendons' ends surgical treatment does not achieve better results than non-operative functional treatment in term of tendon healing and functional outcome. Regarding the current therapeutic standards each method has is advantages and disadvantages. Both, the operative and non-operative functional treatment enable a stable tendon healing with a low risk of re-rupture (1-2%). Meanwhile there is consensus for early functional after-treatment of the operated Achilles' tendons. There seems to be a trend towards non-operative functional treatment in cases of adequate sonographical findings, or to minimal invasive surgical techniques. PMID:10798233

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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.

  13. Endothelial erosion of plaques as a substrate for coronary thrombosis.

    PubMed

    White, Stephen J; Newby, Andrew C; Johnson, Thomas W

    2016-02-29

    Myocardial infarction is a prevalent, life-threatening consequence of athero-thrombosis. Post-mortem histology and intravascular imaging in live patients have shown that approximately one third of myocardial infarctions are caused by a thrombus overlying an intact, non-ruptured atherosclerotic plaque. Histology identifies erosion of luminal endothelial cells from smooth muscle and proteoglycan-rich, thick fibrous cap atheromas as the underlying pathology. Unlike plaque ruptures, endothelial erosions tend to occur on thick-capped atherosclerotic plaques and may or may not be associated with inflammation. Smoking and female gender are strong risk factors for erosion. Multiple mechanisms may contribute to endothelial erosion, including endothelial dysfunction, TLR signalling, leukocyte activation and modification of sub-endothelial matrix by endothelial or smooth muscle cells, which may trigger loss of adhesion to the extracellular matrix or endothelial apoptosis. Diagnosis of endothelial erosion by intravascular imaging, especially high resolution optical coherence tomography, may influence treatment strategies, offering prognostic value and utility as an endpoint in trials of agents designed to preserve an intact coronary endothelium. PMID:26791872

  14. Self-Rupturing Hermetic Valve

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  15. Glass rupture disk

    DOEpatents

    Glass, S. Jill (Albuquerque, NM); Nicolaysen, Scott D. (Albuquerque, NM); Beauchamp, Edwin K. (Albuquerque, NM)

    2002-01-01

    A frangible rupture disk and mounting apparatus for use in blocking fluid flow, generally in a fluid conducting conduit such as a well casing, a well tubing string or other conduits within subterranean boreholes. The disk can also be utilized in above-surface pipes or tanks where temporary and controllable fluid blockage is required. The frangible rupture disk is made from a pre-stressed glass with controllable rupture properties wherein the strength distribution has a standard deviation less than approximately 5% from the mean strength. The frangible rupture disk has controllable operating pressures and rupture pressures.

  16. Pioneer F Plaque Location

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Pioneer F spacecraft, destined to be the first man made object to escape from the solar system into interstellar space, carries this pictorial plaque. It is designed to show scientifically educated inhabitants of some other star system, who might intercept it millions of years from now, when Pioneer was launched, from where, and by what kind of beings. (Hopefully, any aliens reading the plaque will not use this knowledge to immediately invade Earth.) The design is etched into a 6 inch by 9 inch gold-anodized aluminum plate, attached to the spacecraft's attenna support struts in a position to help shield it from erosion by interstellar dust. The radiating lines at left represents the positions of 14 pulsars, a cosmic source of radio energy, arranged to indicate our sun as the home star of our civilization. The '1-' symbols at the ends of the lines are binary numbers that represent the frequencies of these pulsars at the time of launch of Pioneer F relative of that to the hydrogen atom shown at the upper left with a '1' unity symbol. The hydrogen atom is thus used as a 'universal clock,' and the regular decrease in the frequencies of the pulsars will enable another civilization to determine the time that has elapsed since Pioneer F was launched. The hydrogen is also used as a 'universal yardstick' for sizing the human figures and outline of the spacecraft shown on the right. The hydrogen wavelength, about 8 inches, multiplied by the binary number representing '8' shown next to the woman gives her height, 64 inches. The figures represent the type of creature that created Pioneer. The man's hand is raised in a gesture of good will. Across the bottom are the planets, ranging outward from the Sun, with the spacecraft trajectory arching away from Earth, passing Mars, and swinging by Jupiter.

  17. The Immune Response Is Involved in Atherosclerotic Plaque Calcification: Could the RANKL/RANK/OPG System Be a Marker of Plaque Instability?

    PubMed Central

    Montecucco, Fabrizio; Steffens, Sabine; Mach, François

    2007-01-01

    Atherogenesis is characterized by an intense inflammatory process, involving immune and vascular cells. These cells play a crucial role in all phases of atherosclerotic plaque formation and complication through cytokine, protease, and prothrombotic factor secretion. The accumulation of inflammatory cells and thus high amounts of soluble mediators are responsible for the evolution of some plaques to instable phenotype which may lead to rupture. One condition strongly associated with plaque rupture is calcification, a physiopathological process orchestrated by several soluble factors, including the receptor activator of nuclear factor (NF)?B ligand (RANKL)/receptor activator of nuclear factor (NF)?B (RANK)/osteoprotegerin (OPG) system. Although some studies showed some interesting correlations with acute ischemic events, at present, more evidences are needed to evaluate the predictive and diagnostic value of serum sRANKL and OPG levels for clinical use. The major limitation is probably the poor specificity of these factors for cardiovascular disease. The identification of tissue-specific isoforms could increase the importance of sRANKL and OPG in predicting calcified plaque rupture and the dramatic ischemic consequences in the brain and the heart. PMID:18320012

  18. SPECT Imaging Agents for Detecting Cerebral ?-Amyloid Plaques

    PubMed Central

    Ono, Masahiro; Saji, Hideo

    2011-01-01

    The development of radiotracers for use in vivo to image ?-amyloid (A?) plaques in cases of Alzheimer's disease (AD) is an important, active area of research. The presence of A? aggregates in the brain is generally accepted as a hallmark of AD. Since the only definitive diagnosis of AD is by postmortem staining of affected brain tissue, the development of techniques which enable one to image A? plaques in vivo has been strongly desired. Furthermore, the quantitative evaluation of A? plaques in the brain could facilitate evaluation of the efficacy of antiamyloid therapies currently under development. This paper reviews the current situation in the development of agents for SPECT-based imaging of A? plaques in Alzheimer's brains. PMID:21603239

  19. Imaging of the Fibrous Cap in Atherosclerotic Carotid Plaque

    SciTech Connect

    Saba, Luca; Potters, Fons; Lugt, Aad van der; Mallarini, Giorgio

    2010-08-15

    In the last two decades, a substantial number of articles have been published to provide diagnostic solutions for patients with carotid atherosclerotic disease. These articles have resulted in a shift of opinion regarding the identification of stroke risk in patients with carotid atherosclerotic disease. In the recent past, the degree of carotid artery stenosis was the sole determinant for performing carotid intervention (carotid endarterectomy or carotid stenting) in these patients. We now know that the degree of stenosis is only one marker for future cerebrovascular events. If one wants to determine the risk of these events more accurately, other parameters must be taken into account; among these parameters are plaque composition, presence and state of the fibrous cap (FC), intraplaque haemorrhage, plaque ulceration, and plaque location. In particular, the FC is an important structure for the stability of the plaque, and its rupture is highly associated with a recent history of transient ischaemic attack or stroke. The subject of this review is imaging of the FC.

  20. Histopathologic Characteristics of Atherosclerotic Coronary Disease and Implications of the Findings for the Invasive and Noninvasive Detection of Vulnerable Plaques

    PubMed Central

    Narula, Jagat; Nakano, Masataka; Virmani, Renu; Kolodgie, Frank D.; Petersen, Rita; Newcomb, Robert; Malik, Shaista; Fuster, Valentin; Finn, Aloke V.

    2014-01-01

    Objectives The goal of this study was to identify histomorphologic characteristics of atherosclerotic plaques and to determine the amenability of some of these components to be used as markers for invasive and noninvasive imaging. Background Rupture of the atherosclerotic plaques is responsible for the majority of acute coronary events, and the culprit lesions demonstrate distinct histopathologic features. It has been tacitly believed that plaque rupture (PR) is associated with angiographically minimally occlusive lesions. Methods We obtained 295 coronary atherosclerotic plaques, including stable (fibroatheroma [FA]; n = 105), vulnerable (thin-cap fibroatheroma [TCFA]; n = 88), and disrupted plaques (plaque rupture [PR]; n = 102) from the hearts of 181 men and 32 women who had died suddenly. The hierarchical importance of fibrous cap thickness, percent luminal stenosis, macrophage area, necrotic core area, and calcified plaque area was evaluated by using recursive partitioning analysis. Because clinical assessment of fibrous cap thickness is not possible by noninvasive imaging, it was excluded from the second set of partitioning analysis. Results Thickness of the fibrous cap emerged as the best discriminator of plaque type; the cap thickness measured <55 ?m in ruptured plaques, and all FA were associated with >84-?m cap thickness. Although the majority of TCFA were found in the 54- to 84-?m thickness group, those with <54-?m thickness were more likely to show <74% luminal stenosis (area under the curve: FA, 1.0; TCFA, 0.89; PR, 0.90). After exclusion of cap thickness, analysis of the plaque characteristics revealed macrophage infiltration and necrotic core to be the 2 best discriminators of plaque types (area under the curve: FA, 0.82; TCFA, 0.58; PR, 0.72). More than 75% cross-section area stenosis was seen in 70% of PR and 40% of TCFA; only 5% PR and 10% TCFA were <50% narrowed. Conclusions This postmortem study defines histomorphologic characteristics of vulnerable plaques, which may help develop imaging strategies for identification of such plaques in patients at a high risk of sustaining acute coronary events. PMID:23473409

  1. Inflammation, plaque progression and vulnerability: evidence from intravascular ultrasound imaging

    PubMed Central

    Kataoka, Yu; Puri, Rishi

    2015-01-01

    Increasing evidence points to a critical role of inflammation in the development and propagation of atherosclerotic cardiovascular disease. Pathological studies in human and animal models have elucidated specific inflammatory mediators contributing to the progression and rupture of atherosclerotic plaque in the artery wall. These observations not only outline the importance of inflammation in atheroma progression but also the potential of anti-inflammatory therapeutic approaches to prevent and stabilize atherosclerotic disease. Intravascular ultrasonography enables direct atheroma visualization in vivo. Additionally, refinements in ultrasound technology permitting radiofrequency backscatter analysis enhance plaque characterization associated with disease instability. These imaging modalities will continue to provide opportunities for evaluating novel inflammatory mechanisms and anti-inflammatory therapies. PMID:26331112

  2. Making a Lightweight Battery Plaque

    NASA Technical Reports Server (NTRS)

    Reid, M. A.; Post, R. E.; Soltis, D.

    1986-01-01

    Plaque formed in porous plastic by electroless plating. Lightweight plaque prepared by electroless plating of porous plastic contains embedded wire or expanded metal grid. Plastic may or may not be filled with soluble pore former. If it contains soluble pore former, treated to remove soluble pore former and increase porosity. Porous plastic then clamped into rig that allows plating solutions to flow through plastic. Lightweight nickel plaque used as electrode substrate for alkaline batteries, chiefly Ni and Cd electrodes, and for use as electrolyte-reservoir plates for fuel cells.

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

    PubMed Central

    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.

    2012-01-01

    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

  4. Ruptured abdominal aortic aneurysm.

    PubMed

    Sachs, T; Schermerhorn, M

    2010-06-01

    Ruptured abdominal aortic aneurysm (AAA) continues to be one of the most lethal vascular pathologies we encounter. Its management demands prompt and efficient evaluation and repair. Open repair has traditionally been the mainstay of treatment. However, the introduction of endovascular techniques has altered the treatment algorithm for ruptured AAA in most major medical centers. We present recent literature and techniques for ruptured AAA and its surgical management. PMID:20668419

  5. Dental plaque identification at home

    MedlinePLUS

    ... special tablets that contain a red dye that stains the plaque. One tablet is chewed thoroughly, moving ... this method is that it leaves no pink stains in the mouth. In the office, dentists are ...

  6. Disappearance of La Caille Plaque

    NASA Astrophysics Data System (ADS)

    2010-04-01

    A bronze plaque erected to the memory of N.-L. de La Caille near the site of his observatory in Central Cape Town, has been stolen by metal thieves. It was designed by the famous architect Sir Herbert Baker.

  7. Distal biceps and triceps ruptures.

    PubMed

    Kokkalis, Zinon T; Ballas, Efstathios G; Mavrogenis, Andreas F; Soucacos, Panayotis N

    2013-03-01

    Biceps and triceps tendon ruptures are rather uncommon injuries and are most commonly diagnosed clinically. Magnetic resonance imaging can help the clinician to differentiate an incomplete tear and define any degeneration of the tendon. Surgical anatomical repair is typically performed in acute complete ruptures whereas nonoperative treatment can be used for partial ruptures, as well as for patients unfit for surgery. Single incision techniques are associated with a higher rate of nerve injuries, while double incision repairs have a higher prevalence of heterotopic ossification. Although various fixation methods have been applied including bone tunnels, interference screws, suture anchors, cortical button fixation, the current evidence does not support the superiority of one method over the other. A well-planned postoperative rehabilitation programme is essential for a good final outcome. As better fixation devices are being used, more aggressive rehabilitation programmes have been applied. Epidemiology, clinical evaluation, diagnosis, surgical and conservative management of these injuries are presented in this review along with the authors' preferred technique for the anatomical repair of acute complete ruptures. PMID:23352149

  8. Asbestos related pleural plaques in retired boiler room workers.

    PubMed

    Hsiao, T M; Ho, C K; Su, W P; Hwang, J J; Tsai, M S; Chau, T T; Lu, S N; Chang, W Y

    1993-02-01

    Occupational disease is often underestimated and only a few formal reports have been published in Taiwan. This study reports of a group of workers with asbestos-induced-disease, pleural plaque in Taiwan. Pleural plaque is a marker of exposure to asbestos. The disease was found in chest radiographs of five boiler room workers in a sugar refining factory. The chest radiographs of 248 current workers in that plant were reviewed, and none of them was found to have pleural plaques. The storage of asbestos and the long-time use of mixed asbestos cement for insulation of the inner wall of the stove and pipes were found in the factory. The authors believe that the pleural plaques might be resulted from occupational exposure to asbestos. It is suggested that the use of asbestos should be prohibited, step by step, and regular follow-up of the workers with an asbestos exposure history is required. PMID:8492355

  9. An interactive treatment planning system for ophthalmic plaque radiotherapy

    SciTech Connect

    Astrahan, M.A.; Luxton, G.; Jozsef, G.; Kampp, T.D.; Liggett, P.E.; Sapozink, M.D.; Petrovich, Z. )

    1990-03-01

    Brachytherapy using removable episcleral plaques containing sealed radioisotope sources is being studied as an alternative to enucleation in the treatment of choroidal melanoma and other tumors of the eye. Encouraging early results have been reported, but late complications which lead to loss of vision continue to be a problem. A randomized national study, the Collaborative Ocular Melanoma Study (COMS) is currently in progress to evaluate the procedure. The COMS specified isotope is 125I. Precise dosimetric calculations near the plaque may correlate strongly with complications and could also be used to optimize isotope loading patterns in the plaques. A microcomputer based treatment planning system has been developed for ophthalmic plaque brachytherapy. The program incorporates an interactive, 3-dimensional, solid-surface, color-graphic interface. The program currently supports 125I and 192Ir seeds which are treated as anisotropic line sources. Collimation effects related to plaque structure are accounted for, permitting detailed study of shielding effectiveness near the lip of a plaque. A dose distribution matrix may be calculated in any subregion of a transverse, sagittal, or coronal planar cross section of the eye, in any plane transecting the plaque and crossing the eye diametrically, or on a spherical surface within or surrounding the eye. Spherical surfaces may be displayed as 3-dimensional perspective projections or as funduscopic diagrams. Isodose contours are interpolated from the dose matrix. A pointer is also available to explicitly calculate and display dose at any location on the dosimetry surface. An interactive editing capability allows new plaque designs to be rapidly added to the system.

  10. An interactive treatment planning system for ophthalmic plaque radiotherapy.

    PubMed

    Astrahan, M A; Luxton, G; Jozsef, G; Kampp, T D; Liggett, P E; Sapozink, M D; Petrovich, Z

    1990-03-01

    Brachytherapy using removable episcleral plaques containing sealed radioisotope sources is being studied as an alternative to enucleation in the treatment of choroidal melanoma and other tumors of the eye. Encouraging early results have been reported, but late complications which lead to loss of vision continue to be a problem. A randomized national study, the Collaborative Ocular Melanoma Study (COMS) is currently in progress to evaluate the procedure. The COMS specified isotope is 125I. Precise dosimetric calculations near the plaque may correlate strongly with complications and could also be used to optimize isotope loading patterns in the plaques. A microcomputer based treatment planning system has been developed for ophthalmic plaque brachytherapy. The program incorporates an interactive, 3-dimensional, solid-surface, color-graphic interface. The program currently supports 125I and 192Ir seeds which are treated as anisotropic line sources. Collimation effects related to plaque structure are accounted for, permitting detailed study of shielding effectiveness near the lip of a plaque. A dose distribution matrix may be calculated in any subregion of a transverse, sagittal, or coronal planar cross section of the eye, in any plane transecting the plaque and crossing the eye diametrically, or on a spherical surface within or surrounding the eye. Spherical surfaces may be displayed as 3-dimensional perspective projections or as funduscopic diagrams. Isodose contours are interpolated from the dose matrix. A pointer is also available to explicitly calculate and display dose at any location on the dosimetry surface. An interactive editing capability allows new plaque designs to be rapidly added to the system. PMID:2318702

  11. Morphological and Stress Vulnerability Indices for Human Coronary Plaques and Their Correlations with Cap Thickness and Lipid Percent: An IVUS-Based Fluid-Structure Interaction Multi-patient Study

    PubMed Central

    Wang, Liang; Zheng, Jie; Maehara, Akiko; Yang, Chun; Billiar, Kristen L.; Wu, Zheyang; Bach, Richard; Muccigrosso, David; Mintz, Gary S.; Tang, Dalin

    2015-01-01

    Plaque vulnerability, defined as the likelihood that a plaque would rupture, is difficult to quantify due to lack of in vivo plaque rupture data. Morphological and stress-based plaque vulnerability indices were introduced as alternatives to obtain quantitative vulnerability assessment. Correlations between these indices and key plaque features were investigated. In vivo intravascular ultrasound (IVUS) data were acquired from 14 patients and IVUS-based 3D fluid-structure interaction (FSI) coronary plaque models with cyclic bending were constructed to obtain plaque wall stress/strain and flow shear stress for analysis. For the 617 slices from the 14 patients, lipid percentage, min cap thickness, critical plaque wall stress (CPWS), strain (CPWSn) and flow shear stress (CFSS) were recorded, and cap index, lipid index and morphological index were assigned to each slice using methods consistent with American Heart Association (AHA) plaque classification schemes. A stress index was introduced based on CPWS. Linear Mixed-Effects (LME) models were used to analyze the correlations between the mechanical and morphological indices and key morphological factors associated with plaque rupture. Our results indicated that for all 617 slices, CPWS correlated with min cap thickness, cap index, morphological index with r = -0.6414, 0.7852, and 0.7411 respectively (p<0.0001). The correlation between CPWS and lipid percentage, lipid index were weaker (r = 0.2445, r = 0.2338, p<0.0001). Stress index correlated with cap index, lipid index, morphological index positively with r = 0.8185, 0.3067, and 0.7715, respectively, all with p<0.0001. For all 617 slices, the stress index has 66.77% agreement with morphological index. Morphological and stress indices may serve as quantitative plaque vulnerability assessment supported by their strong correlations with morphological features associated with plaque rupture. Differences between the two indices may lead to better plaque assessment schemes when both indices were jointly used with further validations from clinical studies. PMID:26650721

  12. On the effect of calcification volume and configuration on the mechanical behaviour of carotid plaque tissue.

    PubMed

    Barrett, H E; Cunnane, E M; Kavanagh, E G; Walsh, M T

    2016-03-01

    Vascular calcification is a complex molecular process that exhibits a number of relatively characteristic morphology patterns in atherosclerotic plaques. Treatment of arterial stenosis by endovascular intervention, involving forceful circumferential expansion of the plaque, can be unpredictable in calcified lesions. The aim of this study was to determine the mechanical stretching mechanisms and define the mechanical limits for circumferentially expanding carotid plaque lesions under the influence of distinct calcification patterns. Mechanical and structural characterisation was performed on 17 human carotid plaques acquired from patients undergoing endarterectomy procedures. The mechanical properties were determined using uniaxial extension tests that stretch the lesions to complete failure along their circumferential axis. Calcification morphology of mechanically ruptured plaque lesions was characterised using high resolution micro computed tomography imaging. Scanning electron microscopy was used to examine the mechanically induced failure sites and to identify the interface boundary conditions between calcified and non-calcified tissue. The mechanical tests produced four distinct trends in mechanical behaviour which corresponded to the calcification patterns that structurally defined each mechanical group. Each calcification pattern produced unique mechanical restraining effects on the plaque tissue stretching properties evidenced by the variation in degree of stretch to failure. Resistance to failure appears to rely on interactions between calcification and non-calcified tissue. Scanning electron microscopy examination revealed structural gradations at interface boundary conditions to facilitate the transfer of stress. This study emphasises the mechanical influence of distinct calcification configurations on plaque expansion properties and highlights the importance of pre-operative lesion characterisation to optimise treatment outcomes. PMID:26655460

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

    PubMed Central

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

    2013-01-01

    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

  14. Pioneer F Plaque Symbology

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Pioneer F spacecraft, destined to be the first man made object to escape from the solar system into interstellar space, carries this pictorial plaque. It is designed to show scientifically educated inhabitants of some other star system, who might intercept it millions of years from now, when Pioneer was launched, from where, and by what kind of beings. (With the hope that they would not invade Earth.) The design is etched into a 6 inch by 9 inch gold-anodized aluminum plate, attached to the spacecraft's attenna support struts in a position to help shield it from erosion by interstellar dust. The radiating lines at left represents the positions of 14 pulsars, a cosmic source of radio energy, arranged to indicate our sun as the home star of our civilization. The '1-' symbols at the ends of the lines are binary numbers that represent the frequencies of these pulsars at the time of launch of Pioneer F relative of that to the hydrogen atom shown at the upper left with a '1' unity symbol. The hydrogen atom is thus used as a 'universal clock,' and the regular decrease in the frequencies of the pulsars will enable another civilization to determine the time that has elapsed since Pioneer F was launched. The hydrogen is also used as a 'universal yardstick' for sizing the human figures and outline of the spacecraft shown on the right. The hydrogen wavelength, about 8 inches, multiplied by the binary number representing '8' shown next to the woman gives her height, 64 inches. The figures represent the type of creature that created Pioneer. The man's hand is raised in a gesture of good will. Across the bottom are the planets, ranging outward from the Sun, with the spacecraft trajectory arching away from Earth, passing Mars, and swinging by Jupiter.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  16. Spontaneous ruptured hepatocellular carcinoma.

    PubMed

    Yoshida, Hiroshi; Mamada, Yasuhiro; Taniai, Nobuhiko; Uchida, Eiji

    2016-01-01

    The incidence of hepatocellular carcinoma (HCC) is rising worldwide. Spontaneous rupture of HCC occasionally occurs, and ruptured HCC with intraperitoneal hemorrhage is potentially life-threatening. The most common symptom of ruptured HCC is acute abdominal pain. The tumor size in ruptured HCC is significantly greater than that in non-ruptured HCC, and HCC protrudes beyond the original liver margin. In the acute phase, hemostasis is the primary concern and tumor treatment is secondary. Transcatheter arterial embolization (TAE) can effectively induce hemostasis. The hemostatic success rate of TAE ranges 53-100%. A one-stage surgical operation is a treatment modality for selected patients. Conservative treatment is usually given to patients in a moribund state with inoperable tumors and thus has poor outcomes. Patients with severe ruptures of advanced HCC and poor liver function have high mortality rates. Liver failure occurs in 12-42% of patients during the acute phase. In the stable phase, tumor treatment, such as transarterial chemoembolization or hepatic resection should be concerned. The combination of acute hemorrhage and cancer in patients with ruptured HCC requires a two-step therapeutic approach. TAE followed by elective hepatectomy is considered an effective strategy for patients with ruptured HCC. PMID:25631290

  17. Application of IR and NIR fiber optic imaging in thermographic and spectroscopic diagnosis of atherosclerotic vulnerable plaques: preliminary experience

    NASA Astrophysics Data System (ADS)

    Naghavi, Morteza; Khan, Tania; Gu, Bujin; Soller, Babs R.; Melling, Peter; Asif, Mohammed; Gul, Khawar; Madjid, Mohammad; Casscells, S. W.; Willerson, James T.

    2000-12-01

    Despite major advances in cardiovascular science and technology during the past three decades, approximately half of all myocardial infarctions and sudden deaths occur unexpectedly. It is widely accepted that coronary atherosclerotic plaques and thrombotic complications resulting from their rupture or erosion are the underlying causes of this major health problem. The majority of these vulnerable plaques exhibit active inflammation, a large necrotic lipid core, a thin fibrous cap, and confer a stenosis of less than 70%. These lesions are not detectable by stress testing or coronary angiography. Our group is exploring the possibility of a functional classification based on physiological variables such as plaque temperature, pH, oxygen consumption, lactate production etc. We have shown that heat accurately locates the inflamed plaques. We also demonstrated human atherosclerotic plaques are heterogeneous with regard to pH and hot plaques and are more likely to be acidic. To develop a nonsurgical method for locating the inflamed plaques, we are developing both IR fiber optic imaging and NIR spectroscopic systems in our laboratory to detect hot and acidic plaque in atherosclerotic arterial walls. Our findings introduce the possibility of an isolated/combined IR and NIR fiber optic catheter that can bring new insight into functional assessment of atherosclerotic plaque and thereby detection of active and inflamed lesions responsible for heart attacks and strokes.

  18. The influence of plaque composition on underlying arterial wall stress during stent expansion: the case for lesion-specific stents.

    PubMed

    Pericevic, Ian; Lally, Caitríona; Toner, Deborah; Kelly, Daniel John

    2009-05-01

    Intracoronary stent implantation is a mechanical procedure, the success of which depends to a large degree on the mechanical properties of each vessel component involved and the pressure applied to the balloon. Little is known about the influence of plaque composition on arterial overstretching and the subsequent injury to the vessel wall following stenting. An idealised finite element model was developed to investigate the influence of both plaque types (hypercellular, hypocellular and calcified) and stent inflation pressures (9, 12 and 15 atm) on vessel and plaque stresses during the implantation of a balloon expandable coronary stent into an idealised stenosed artery. The plaque type was found to have a significant influence on the stresses induced within the artery during stenting. Higher stresses were predicted in the artery wall for cellular plaques, while the stiffer calcified plaque appeared to play a protective role by reducing the levels of stress within the arterial tissue for a given inflation pressure. Higher pressures can be applied to calcified plaques with a lower risk of arterial vascular injury which may reduce the stimulus for in-stent restenosis. Results also suggest that the risk of plaque rupture, and any subsequent thrombosis due to platelet deposition at the fissure, is greater for calcified plaques with low fracture stresses. PMID:19129001

  19. Regulation of atherosclerotic plaque inflammation.

    PubMed

    Bäck, M; Weber, C; Lutgens, E

    2015-11-01

    The immune reactions that regulate atherosclerotic plaque inflammation involve chemokines, lipid mediators and costimulatory molecules. Chemokines are a family of chemotactic cytokines that mediate immune cell recruitment and control cell homeostasis and activation of different immune cell types and subsets. Chemokine production and activation of chemokine receptors form a positive feedback mechanism to recruit monocytes, neutrophils and lymphocytes into the atherosclerotic plaque. In addition, chemokine signalling affects immune cell mobilization from the bone marrow. Targeting several of the chemokines and/or chemokine receptors reduces experimental atherosclerosis, whereas specific chemokine pathways appear to be involved in plaque regression. Leukotrienes are lipid mediators that are formed locally in atherosclerotic lesions from arachidonic acid. Leukotrienes mediate immune cell recruitment and activation within the plaque as well as smooth muscle cell proliferation and endothelial dysfunction. Antileukotrienes decrease experimental atherosclerosis, and recent observational data suggest beneficial clinical effects of leukotriene receptor antagonism in cardiovascular disease prevention. By contrast, other lipid mediators, such as lipoxins and metabolites of omega-3 fatty acids, have been associated with the resolution of inflammation. Costimulatory molecules play a central role in fine-tuning immunological reactions and mediate crosstalk between innate and adaptive immunity in atherosclerosis. Targeting these interactions is a promising approach for the treatment of atherosclerosis, but immunological side effects are still a concern. In summary, targeting chemokines, leukotriene receptors and costimulatory molecules could represent potential therapeutic strategies to control atherosclerotic plaque inflammation. PMID:25823439

  20. Identification of High-Risk Plaques by MRI and Fluorescence Imaging in a Rabbit Model of Atherothrombosis

    PubMed Central

    Hua, Ning; Baik, Fred; Pham, Tuan; Phinikaridou, Alkystis; Giordano, Nick; Friedman, Beth; Whitney, Michael; Nguyen, Quyen T.; Tsien, Roger Y.; Hamilton, James A.

    2015-01-01

    Introduction The detection of atherosclerotic plaques at risk for disruption will be greatly enhanced by molecular probes that target vessel wall biomarkers. Here, we test if fluorescently-labeled Activatable Cell Penetrating Peptides (ACPPs) could differentiate stable plaques from vulnerable plaques that disrupt, forming a luminal thrombus. Additionally, we test the efficacy of a combined ACPP and MRI technique for identifying plaques at high risk of rupture. Methods and Results In an atherothrombotic rabbit model, disrupted plaques were identified with in vivo MRI and co-registered in the same rabbit aorta with the in vivo uptake of ACPPs, cleaved by matrix metalloproteinases (MMPs) or thrombin. ACPP uptake, mapped ex vivo in whole aortas, was higher in disrupted compared to non-disrupted plaques. Specifically, disrupted plaques demonstrated a 4.5~5.0 fold increase in fluorescence enhancement, while non-disrupted plaques showed only a 2.2~2.5 fold signal increase. Receiver operating characteristic (ROC) analysis indicates that both ACPPs (MMP and thrombin) show high specificity (84.2% and 83.2%) and sensitivity (80.0% and 85.7%) in detecting disrupted plaques. The detection power of ACPPs was improved when combined with the MRI derived measure, outward remodeling ratio. Conclusions Our targeted fluorescence ACPP probes distinguished disrupted plaques from stable plaques with high sensitivity and specificity. The combination of anatomic, MRI-derived predictors for disruption and ACPP uptake can further improve the power for identification of high-risk plaques and suggests future development of ACPPs with molecular MRI as a readout. PMID:26448434

  1. Characterizing atherosclerotic plaque with computed tomography: a contrast-detail study

    NASA Astrophysics Data System (ADS)

    Kasraie, Nima; Clarke, Geoffrey D.

    2012-02-01

    Plaque characterization may benefit from the increasing distinctiveness of the attenuating properties of different soft plaque components at lower energies. Due to the relative slight increase in the CT number of the nonadipose soft plaque at lower tube voltage settings vs. adipose plaque, a higher contrast between atheromous adipose and non-adipose plaque may become visible with modern 64 slice systems. A contrast-detail (C-D) phantom with varying plaque composition as the contrast generating method, was imaged on a commercial 64 slice MDCT system using 80, 120, and 140 kVp settings. The same phantom was also imaged on a Cone Beam CT (CBCT) system with a lower tube voltage of 75 kVp. The results of experiments from four different observers on three different plaque types (lipid, fiber, calcific) indicate that CT attenuation within lipid cores and fibrous masses vary not only with the percentage of lipid or fiber present, but also with the size of the cores. Furthermore, the C-D curve analysis for all three plaque types reveals that while the noise constraints prevent visible differentiation of soft plaque at current conventional 64 slice MDCT settings, CBCT exhibits superior visible contrast detectability than its conventional counterpart, with the latter having appreciably better resolution limits and beneficial lower tube voltages. This low voltage CT technique has the potential to be useful in composition based diagnosis of carotid vulnerable atherosclerotic plaque.

  2. Leukotriene B4 Levels in Human Atherosclerotic Plaques and Abdominal Aortic Aneurysms

    PubMed Central

    van den Borne, Pleunie; van der Laan, Sander W.; Bovens, Sandra M.; Koole, Dave; Kowala, Mark C.; Michael, Laura F.; Schoneveld, Arjan H.; van de Weg, Sander M.; Velema, Evelyn; de Vries, Jean-Paul; de Borst, Gert J.; Moll, Frans L.; de Kleijn, Dominique P. V.; Quax, Paul H. A.; Hoefer, Imo E.; Pasterkamp, Gerard

    2014-01-01

    Background Leukotriene B4 (LTB4) has been associated with the initiation and progression of atherosclerosis and abdominal aortic aneurysm (AAA) formation. However, associations of LTB4 levels with tissue characteristics and adverse clinical outcome of advanced atherosclerosis and AAA are scarcely studied. We hypothesized that LTB4 levels are associated with a vulnerable plaque phenotype and adverse clinical outcome. Furthermore, that LTB4 levels are associated with inflammatory AAA and adverse clinical outcome. Methods Atherosclerotic plaques and AAA specimens were selected from two independent databases for LTB4 measurements. Plaques were isolated during carotid endarterectomy from asymptomatic (n?=?58) or symptomatic (n?=?317) patients, classified prior to surgery. LTB4 levels were measured without prior lipid extraction and levels were corrected for protein content. LTB4 levels were related to plaque phenotype, baseline patient characteristics and clinical outcome within three years following surgery. Seven non-diseased mammary artery specimens served as controls. AAA specimens were isolated during open repair, classified as elective (n?=?189), symptomatic (n?=?29) or ruptured (n?=?23). LTB4 levels were measured similar to the plaque measurements and were related to tissue characteristics, baseline patient characteristics and clinical outcome. Twenty-six non-diseased aortic specimens served as controls. Results LTB4 levels corrected for protein content were not significantly associated with histological characteristics specific for vulnerable plaques or inflammatory AAA as well as clinical presentation. Moreover, it could not predict secondary manifestations independently investigated in both databases. However, LTB4 levels were significantly lower in controls compared to plaque (p?=?0.025) or AAA (p?=?0.017). Conclusions LTB4 levels were not associated with a vulnerable plaque phenotype or inflammatory AAA or clinical presentation. This study does not provide supportive evidence for a role of LTB4 in atherosclerotic plaque destabilization or AAA expansion. However, these data should be interpreted with care, since LTB4 measurements were performed without prior lipid extractions. PMID:24475136

  3. Triple cardiac rupture.

    PubMed

    Vazquez, Alejandro; Osa, Ana; Vicente, Rosario; Montero, Jose A

    2014-09-01

    Left ventricular free wall rupture and acute ischaemic mitral regurgitation are nowadays rare, but still potentially lethal mechanical complications after acute myocardial infarction. We report a case of a sequential left ventricular free wall rupture, anterolateral papillary muscle disruption, secondary severe mitral regurgitation and subsequent posteromedial papillary muscle head rupture in a single patient during the same ischaemic episode after myocardial infarction, and their related successful surgical procedures and management until discharge. Prompt bedside diagnosis and emergent consecutive surgical procedures, as well as temporary left ventricular assistance, were crucial in the survival of this patient. PMID:24876216

  4. Intravascular probe for detection of vulnerable plaque

    NASA Astrophysics Data System (ADS)

    Patt, Bradley E.; Iwanczyk, Jan S.; MacDonald, Lawrence R.; Yamaguchi, Yuko; Tull, Carolyn R.; Janecek, Martin; Hoffman, Edward J.; Strauss, H. William; Tsugita, Ross; Ghazarossian, Vartan

    2001-12-01

    Coronary angiography is unable to define the status of the atheroma, and only measures the luminal dimensions of the blood vessel, without providing information about plaque content. Up to 70% of heart attacks are caused by minimally obstructive vulnerable plaques, which are too small to be detected adequately by angiography. We have developed an intravascular imaging detector to identify vulnerable coronary artery plaques. The detector works by sensing beta or conversion electron radiotracer emissions from plaque-binding radiotracers. The device overcomes the technical constraints of size, sensitivity and conformance to the intravascular environment. The detector at the distal end of the catheter uses six 7mm long by 0.5mm diameter scintillation fibers coupled to 1.5m long plastic fibers. The fibers are offset from each other longitudinally by 6mm and arranged spirally around a guide wire in the catheter. At the proximal end of the catheter the optical fibers are coupled to an interface box with a snap on connector. The interface box contains a position sensitive photomultiplier tube (PSPMT) to decode the individual fibers. The whole detector assembly fits into an 8-French (2.7 mm in diameter) catheter. The PSPMT image is further decoded with software to give a linear image, the total instantaneous count rate and an audio output whose tone corresponds to the count rate. The device was tested with F-18 and Tl-204 sources. Spectrometric response, spatial resolution, sensitivity and beta to background ratio were measured. System resolution is 6 mm and the sensitivity is >500 cps / micrometers Ci when the source is 1 mm from the detector. The beta to background ratio was 11.2 for F-18 measured on a single fiber. The current device will lead to a system allowing imaging of labeled vulnerable plaque in coronary arteries. This type of signature is expected to enable targeted and cost effective therapies to prevent acute coronary artery diseases such as: unstable angina, acute myocardial infarction, and sudden cardiac death.

  5. Molecular Imaging of Plaque Vulnerability

    PubMed Central

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

    2014-01-01

    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 preclinical stage, few techniques (e.g., 18F-FDG and 18F-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

  6. Ruptured visceral artery aneurysms.

    PubMed

    Chiaradia, M; Novelli, L; Deux, J-F; Tacher, V; Mayer, J; You, K; Djabbari, M; Luciani, A; Rahmouni, A; Kobeiter, H

    2015-01-01

    Visceral artery aneurysms are rare but their estimated mortality due to rupture ranges between 25 and 70%. Treatment of visceral artery aneurysm rupture is usually managed by interventional radiology. Specific embolization techniques depend on the location, affected organ, locoregional arterial anatomy, and interventional radiologist skill. The success rate following treatment by interventional radiology is greater than 90%. The main complication is recanalization of the aneurysm, showing the importance of post-therapeutic monitoring, which should preferably be performed using MR imaging. PMID:26054246

  7. A uni-extension study on the ultimate material strength and extreme extensibility of atherosclerotic tissue in human carotid plaques

    PubMed Central

    Teng, Zhongzhao; Feng, Jiaxuan; Zhang, Yongxue; Sutcliffe, Michael P.F.; Huang, Yuan; Brown, Adam J.; Jing, Zaiping; Lu, Qingsheng; Gillard, Jonathan H.

    2015-01-01

    Atherosclerotic plaque rupture occurs when mechanical loading exceeds its material strength. Mechanical analysis has been shown to be complementary to the morphology and composition for assessing vulnerability. However, strength and stretch thresholds for mechanics-based assessment are currently lacking. This study aims to quantify the ultimate material strength and extreme extensibility of atherosclerotic components from human carotid plaques. Tissue strips of fibrous cap, media, lipid core and intraplaque hemorrhage/thrombus were obtained from 21 carotid endarterectomy samples of symptomatic patients. Uni-extension test with tissue strips was performed until they broke or slid. The Cauchy stress and stretch ratio at the peak loading of strips broken about 2 mm away from the clamp were used to characterize their ultimate strength and extensibility. Results obtained indicated that ultimate strength of fibrous cap and media were 158.3 [72.1, 259.3] kPa (Median [Inter quartile range]) and 247.6 [169.0, 419.9] kPa, respectively; those of lipid and intraplaque hemorrhage/thrombus were 68.8 [48.5, 86.6] kPa and 83.0 [52.1, 124.9] kPa, respectively. The extensibility of each tissue type were: fibrous cap – 1.18 [1.10, 1.27]; media – 1.21 [1.17, 1.32]; lipid – 1.25 [1.11, 1.30] and intraplaque hemorrhage/thrombus – 1.20 [1.17, 1.44]. Overall, the strength of fibrous cap and media were comparable and so were lipid and intraplaque hemorrhage/thrombus. Both fibrous cap and media were significantly stronger than either lipid or intraplaque hemorrhage/thrombus. All atherosclerotic components had similar extensibility. Moreover, fibrous cap strength in the proximal region (closer to the heart) was lower than that of the distal. These results are helpful in understanding the material behavior of atherosclerotic plaques. PMID:26472304

  8. [Iatrogenic postintubation tracheal rupture].

    PubMed

    Parshin, V D; Pogodina, A N; Vyzhigina, M A; Rusakov, M A

    2006-01-01

    Iatrogenic damage to the trachea in its intubation and during artificial lung ventilation ,is a rare, severe and commonly fatal complication in resuscitative care. The risk for tracheal damage increases in emergency, time shortage and hypoxia in a patient, while intubating with a double-lumen tube, using rigid mandrin guides without a safety limit stop, and having difficulties in intubating the patient due to his/her anatomic features. Fibrotracheoscopy is the principal diagnostic techniques that may cause tracheal rupture, which may be transformed to a therapeutic measure, by placing an intubation tube caudally at the site of tracheal rupture. Among 33 patients, only 6 underwent surgical defect suturing. When the trachea is ruptured, surgery is indicated for respiratory hemorrhage unstopped by inflating the cuff of an intubation tube and, perhaps, associated with the damage to a large vessel; for progressive gas syndrome, extensive rupture of the membranous part with the involvement of the tracheal bifurcation and main bronchus or with the interposition of paratracheal tissues; for a concomitant damage to the esophagus; for rupture of the tracheal membranous part during intubation before thoracotomy or for rupture detected during thoracotomy for another cause. Correct and timely care may eliminate this life-threatening iatrogenic complication, by yielding a good effect. PMID:16758936

  9. Pharmacogenomic interaction between the Haptoglobin genotype and vitamin E on atherosclerotic plaque progression and stability

    PubMed Central

    Veiner, Hilla-Lee; Gorbatov, Rostic; Vardi, Moshe; Doros, Gheorghe; Miller-Lotan, Rachel; Zohar, Yaniv; Sabo, Edmond; Asleh, Rabea; Levy, Nina S.; Goldfarb, Levi J.; Berk, Thomas A.; Haas, Tali; Shalom, Hadar; Suss-Toby, Edith; Kam, Adi; Kaplan, Marielle; Tamir, Ronit; Ziskind, Anna; Levy, Andrew P.

    2015-01-01

    Structured Abstract Objective Homozygosity for a 1.7kb intragenic duplication of the Haptoglobin (Hp) gene (Hp 2-2 genotype), present in 36% of the population, has been associated with a 2–3 fold increased incidence of atherothrombosis in individuals with Diabetes (DM) in 10 longitudinal studies compared to DM individuals not homozygous for this duplication (Hp 1-1/2-1). The increased CVD risk associated with the Hp 2-2 genotype has been shown to be prevented with vitamin E supplementation in man. We sought to determine if there was an interaction between the Hp genotype and vitamin E on atherosclerotic plaque growth and stability in a transgenic model of the Hp polymorphism. Methods and Results Brachiocephalic artery atherosclerotic plaque volume was serially assessed by high resolution ultrasound in 28 Hp 1-1 and 26 Hp 2-2 mice in a C57Bl/6 ApoE−/− background. Hp 2-2 mice had more rapid plaque growth and an increased incidence of plaque hemorrhage and rupture. Vitamin E significantly reduced plaque growth in Hp 2-2 but not in Hp 1-1 mice with a significant pharmacogenomic interaction between the Hp genotype and vitamin E on plaque growth. Conclusions These results may help explain why vitamin E supplementation in man can prevent CVD in Hp 2-2 DM but not in non Hp 2-2 DM individuals. PMID:25618031

  10. Imaging Plaques to Predict and Better Manage Patients with Acute Coronary Events

    PubMed Central

    Garcia-Garcia, Hector M.; Jang, Ik-Kyung; Serruys, Patrick W.; Kovacic, Jason C.; Narula, Jagat; Fayad, Zahi A.

    2014-01-01

    Culprit lesions of patients who have had an acute coronary syndrome commonly are ruptured coronary plaques with superimposed thrombus. The precursor of such lesions is an inflamed thin-capped fibroatheroma. These plaques can be imaged by means of invasive techniques such as intravascular ultrasound (and derived techniques), optical coherence tomography and near-infrared spectroscopy. Very often these patients exhibit similar (multiple) plaques beyond the culprit lesion. These remote plaques can be assessed non invasively by computed tomography angiography and magnetic resonance imaging and also using invasive imaging. The detection of these remote plaques is not only feasible, but also in natural history studies have been associated with clinical coronary events. Different systemic pharmacological treatments have been studied (mostly statins) with modest success and therefore newer approaches are being tested. Local treatment for such lesions is in its infancy and larger, prospective and randomized trials are needed. This review will describe the pathological and imaging findings in culprit lesions of patients with acute coronary syndrome and as well as the assessment of remote plaques. In addition, the pharmacological and local treatment options will be reviewed. PMID:24902974

  11. Contribution of neovascularization and intraplaque haemorrhage to atherosclerotic plaque progression and instability.

    PubMed

    Chistiakov, D A; Orekhov, A N; Bobryshev, Y V

    2015-03-01

    Atherosclerosis is a continuous pathological process that starts early in life and progresses frequently to unstable plaques. Plaque rupture leads to deleterious consequences such as acute coronary syndrome, stroke and atherothrombosis. The vulnerable lesion has several structural and functional hallmarks that distinguish it from the stable plaque. The unstable plaque has large necrotic core (over 40% plaque volume) composed of cholesterol crystals, cholesterol esters, oxidized lipids, fibrin, erythrocytes and their remnants (haeme, iron, haemoglobin), and dying macrophages. The fibrous cap is thin, depleted of smooth muscle cells and collagen, and is infiltrated with proinflammatory cells. In unstable lesion, formation of neomicrovessels is increased. These neovessels have weak integrity and leak thereby leading to recurrent haemorrhages. Haemorrhages deliver erythrocytes to the necrotic core where they degrade promoting inflammation and oxidative stress. Inflammatory cells mostly presented by monocytes/macrophages, neutrophils and mast cells extravagate from bleeding neovessels and infiltrate adventitia where they support chronic inflammation. Plaque destabilization is an evolutionary process that could start at early atherosclerotic stages and whose progression is influenced by many factors including neovascularization, intraplaque haemorrhages, formation of cholesterol crystals, inflammation, oxidative stress and intraplaque protease activity. PMID:25515699

  12. Intravascular optical imaging of high-risk plaques in vivo by targeting macrophage mannose receptors.

    PubMed

    Kim, Ji Bak; Park, Kyeongsoon; Ryu, Jiheun; Lee, Jae Joong; Lee, Min Woo; Cho, Han Saem; Nam, Hyeong Soo; Park, Ok Kyu; Song, Joon Woo; Kim, Tae Shik; Oh, Dong Joo; Gweon, DaeGab; Oh, Wang-Yuhl; Yoo, Hongki; Kim, Jin Won

    2016-01-01

    Macrophages mediate atheroma expansion and disruption, and denote high-risk arterial plaques. Therefore, they are substantially gaining importance as a diagnostic imaging target for the detection of rupture-prone plaques. Here, we developed an injectable near-infrared fluorescence (NIRF) probe by chemically conjugating thiolated glycol chitosan with cholesteryl chloroformate, NIRF dye (cyanine 5.5 or 7), and maleimide-polyethylene glycol-mannose as mannose receptor binding ligands to specifically target a subset of macrophages abundant in high-risk plaques. This probe showed high affinity to mannose receptors, low toxicity, and allowed the direct visualization of plaque macrophages in murine carotid atheroma. After the scale-up of the MMR-NIRF probe, the administration of the probe facilitated in vivo intravascular imaging of plaque inflammation in coronary-sized vessels of atheromatous rabbits using a custom-built dual-modal optical coherence tomography (OCT)-NIRF catheter-based imaging system. This novel imaging approach represents a potential imaging strategy enabling the identification of high-risk plaques in vivo and holds promise for future clinical implications. PMID:26948523

  13. Intravascular optical imaging of high-risk plaques in vivo by targeting macrophage mannose receptors

    PubMed Central

    Kim, Ji Bak; Park, Kyeongsoon; Ryu, Jiheun; Lee, Jae Joong; Lee, Min Woo; Cho, Han Saem; Nam, Hyeong Soo; Park, Ok Kyu; Song, Joon Woo; Kim, Tae Shik; Oh, Dong Joo; Gweon, DaeGab; Oh, Wang-Yuhl; Yoo, Hongki; Kim, Jin Won

    2016-01-01

    Macrophages mediate atheroma expansion and disruption, and denote high-risk arterial plaques. Therefore, they are substantially gaining importance as a diagnostic imaging target for the detection of rupture-prone plaques. Here, we developed an injectable near-infrared fluorescence (NIRF) probe by chemically conjugating thiolated glycol chitosan with cholesteryl chloroformate, NIRF dye (cyanine 5.5 or 7), and maleimide-polyethylene glycol-mannose as mannose receptor binding ligands to specifically target a subset of macrophages abundant in high-risk plaques. This probe showed high affinity to mannose receptors, low toxicity, and allowed the direct visualization of plaque macrophages in murine carotid atheroma. After the scale-up of the MMR-NIRF probe, the administration of the probe facilitated in vivo intravascular imaging of plaque inflammation in coronary-sized vessels of atheromatous rabbits using a custom-built dual-modal optical coherence tomography (OCT)-NIRF catheter-based imaging system. This novel imaging approach represents a potential imaging strategy enabling the identification of high-risk plaques in vivo and holds promise for future clinical implications. PMID:26948523

  14. Vulnerable Atherosclerotic Plaque Elasticity Reconstruction Based on a Segmentation-Driven Optimization Procedure Using Strain Measurements: Theoretical Framework

    PubMed Central

    Le Floc’h, Simon; Tracqui, Philippe; Finet, Gérard; Gharib, Ahmed M.; Maurice, Roch L.; Cloutier, Guy; Pettigrew, Roderic I.

    2016-01-01

    It is now recognized that prediction of the vulnerable coronary plaque rupture requires not only an accurate quantification of fibrous cap thickness and necrotic core morphology but also a precise knowledge of the mechanical properties of plaque components. Indeed, such knowledge would allow a precise evaluation of the peak cap-stress amplitude, which is known to be a good biomechanical predictor of plaque rupture. Several studies have been performed to reconstruct a Young’s modulus map from strain elastograms. It seems that the main issue for improving such methods does not rely on the optimization algorithm itself, but rather on preconditioning requiring the best estimation of the plaque components’ contours. The present theoretical study was therefore designed to develop: 1) a preconditioning model to extract the plaque morphology in order to initiate the optimization process, and 2) an approach combining a dynamic segmentation method with an optimization procedure to highlight the modulogram of the atherosclerotic plaque. This methodology, based on the continuum mechanics theory prescribing the strain field, was successfully applied to seven intravascular ultrasound coronary lesion morphologies. The reconstructed cap thickness, necrotic core area, calcium area, and the Young’s moduli of the calcium, necrotic core, and fibrosis were obtained with mean relative errors of 12%, 4% and 1%, 43%, 32%, and 2%, respectively. PMID:19164080

  15. Comparison of the effects of pitavastatin versus pravastatin on coronary artery plaque phenotype assessed by tissue characterization using serial virtual histology intravascular ultrasound.

    PubMed

    Nozue, Tsuyoshi; Yamamoto, Shingo; Tohyama, Shinichi; Fukui, Kazuki; Umezawa, Shigeo; Onishi, Yuko; Kunishima, Tomoyuki; Sato, Akira; Nozato, Toshihiro; Miyake, Shogo; Takeyama, Youichi; Morino, Yoshihiro; Yamauchi, Takao; Muramatsu, Toshiya; Hibi, Kiyoshi; Terashima, Mitsuyasu; Michishita, Ichiro

    2015-01-01

    Thin-cap fibroatheroma (TCFA) is the most common type of vulnerable plaque and is the precursor of plaque rupture. However, rupture of a TCFA is not the only mechanism underlying thrombus formation or acute coronary syndrome. Although statin therapy changes the composition of coronary artery plaques, the effects of statins, particularly different types of statins, on plaque phenotype have not been fully examined. This study compared the effects of pitavastatin versus pravastatin on coronary artery plaque phenotype assessed by virtual histology (VH) intravascular ultrasound (IVUS) in patients with angina pectoris (AP). Coronary atherosclerosis in nonculprit lesions was evaluated using VH-IVUS at baseline and 8 months after statin therapy; analyzable IVUS data were obtained from 83 patients with stable AP (39 patients treated with pitavastatin and 44 with pravastatin) and 36 patients with unstable AP (19 patients treated with pitavastatin and 17 with pravastatin). Pitavastatin had a strong effect on reducing pathologic intimal thickening (PIT), especially in patients with unstable AP, but had no impact on VH-TCFA or fibroatheroma (FA). By contrast, pravastatin had weak effects on reducing PIT, VH-TCFA, or FA. Increases in the number of calcified plaques were observed for both statins. In conclusion, pitavastatin and pravastatin changed coronary artery plaque phenotype as assessed by VH-IVUS in patients with AP. However, the effects of these statins on coronary artery plaque phenotype were different. PMID:24337500

  16. Optical detection of structural changes in human carotid atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

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

    2005-08-01

    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 μm. 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.

  17. Anti‐Inflammatory Immune Skewing Is Atheroprotective: Apoe−/−FcγRIIb−/− Mice Develop Fibrous Carotid Plaques

    PubMed Central

    Harmon, Erin Y.; Fronhofer, Van; Keller, Rebecca S.; Feustel, Paul J.; Zhu, Xinmei; Xu, Hao; Avram, Dorina; Jones, David M.; Nagarajan, Shanmugam; Lennartz, Michelle R.

    2014-01-01

    Background Stroke, caused by carotid plaque rupture, is a major cause of death in the United States. Whereas vulnerable human plaques have higher Fc receptor (FcγR) expression than their stable counterparts, how FcγR expression impacts plaque histology is unknown. We investigated the role of FcγRIIb in carotid plaque development and stability in apolipoprotein (Apo)e−/− and Apoe−/−FcγRIIb−/− double knockout (DKO) animals. Methods and Results Plaques were induced by implantation of a shear stress‐modifying cast around the carotid artery. Plaque length and stenosis were followed longitudinally using ultrasound biomicroscopy. Immune status was determined by flow cytometry, cytokine release, immunoglobulin G concentration and analysis of macrophage polarization both in plaques and in vitro. Surprisingly, DKO animals had lower plaque burden in both carotid artery and descending aorta. Plaques from Apoe−/− mice were foam‐cell rich and resembled vulnerable human specimens, whereas those from DKO mice were fibrous and histologically stable. Plaques from DKO animals expressed higher arginase 1 (Arg‐1) and lower inducible nitric oxide synthase (iNOS), indicating the presence of M2 macrophages. Analysis of blood and cervical lymph nodes revealed higher interleukin (IL)‐10, immune complexes, and regulatory T cells (Tregs) and lower IL‐12, IL‐1β, and tumor necrosis factor alpha (TNF‐α) in DKO mice. Similarly, in vitro stimulation produced higher IL‐10 and Arg‐1 and lower iNOS, IL‐1β, and TNF‐α in DKO versus Apoe−/− macrophages. These results define a systemic anti‐inflammatory phenotype. Conclusions We hypothesized that removal of FcγRIIb would exacerbate atherosclerosis and generate unstable plaques. However, we found that deletion of FcγRIIb on a congenic C57BL/6 background induces an anti‐inflammatory Treg/M2 polarization that is atheroprotective. PMID:25516435

  18. Mathematical modeling and simulation of the evolution of plaques in blood vessels.

    PubMed

    Yang, Yifan; Jäger, Willi; Neuss-Radu, Maria; Richter, Thomas

    2016-03-01

    In this paper, a model is developed for the evolution of plaques in arteries, which is one of the main causes for the blockage of blood flow. Plaque rupture and spread of torn-off material may cause closures in the down-stream vessel system and lead to ischemic brain or myocardial infarctions. The model covers the flow of blood and its interaction with the vessel wall. It is based on the assumption that the penetration of monocytes from the blood flow into the vessel wall, and the accumulation of foam cells increasing the volume, are main factors for the growth of plaques. The dynamics of the vessel wall is governed by a deformation gradient, which is given as composition of a purely elastic tensor, and a tensor modeling the biologically caused volume growth. An equation for the evolution of the metric is derived quantifying the changing geometry of the vessel wall. To calculate numerically the solutions of the arising free boundary problem, the model system of partial differential equations is transformed to an ALE (Arbitrary Lagrangian-Eulerian) formulation, where all equations are given in fixed domains. The numerical calculations are using newly developed algorithms for ALE systems. The results of the simulations, obtained for realistic system parameters, are in good qualitative agreement with observations. They demonstrate that the basic modeling assumption can be justified. The increase of stresses in the vessel wall can be computed. Medical treatment tries to prevent critical stress values, which may cause plaque rupture and its consequences. PMID:26385578

  19. Three-Dimensional Ultrasound of Carotid Plaque.

    PubMed

    Spence, J David; Parraga, Grace

    2016-02-01

    Measurement of plaque burden is different from measurement of carotid intima-media thickness (IMT). Carotid total plaque area is a stronger predictor of cardiovascular risk than IMT, and in contrast to progression of IMT, which does not predict cardiovascular events, progression of total plaque area and total plaque volume strongly predict cardiovascular events. Measurement of plaque burden is useful in genetic research, and in evaluation of new therapies for atherosclerosis. Perhaps more importantly, it can be used for management of patients. A strategy called "treating arteries instead of treating risk factors" markedly reduces risk among patients with asymptomatic carotid stenosis. PMID:26610661

  20. Human coronary plaque wall thickness correlated positively with flow shear stress and negatively with plaque wall stress: an IVUS-based fluid-structure interaction multi-patient study

    PubMed Central

    2014-01-01

    Background Atherosclerotic plaque progression and rupture are believed to be associated with mechanical stress conditions. In this paper, patient-specific in vivo intravascular ultrasound (IVUS) coronary plaque image data were used to construct computational models with fluid-structure interaction (FSI) and cyclic bending to investigate correlations between plaque wall thickness and both flow shear stress and plaque wall stress conditions. Methods IVUS data were acquired from 10 patients after voluntary informed consent. The X-ray angiogram was obtained prior to the pullback of the IVUS catheter to determine the location of the coronary artery stenosis, vessel curvature and cardiac motion. Cyclic bending was specified in the model representing the effect by heart contraction. 3D anisotropic FSI models were constructed and solved to obtain flow shear stress (FSS) and plaque wall stress (PWS) values. FSS and PWS values were obtained for statistical analysis. Correlations with p < 0.05 were deemed significant. Results Nine out of the 10 patients showed positive correlation between wall thickness and flow shear stress. The mean Pearson correlation r-value was 0.278 ± 0.181. Similarly, 9 out of the 10 patients showed negative correlation between wall thickness and plaque wall stress. The mean Pearson correlation r-value was -0.530 ± 0.210. Conclusion Our results showed that plaque vessel wall thickness correlated positively with FSS and negatively with PWS. The patient-specific IVUS-based modeling approach has the potential to be used to investigate and identify possible mechanisms governing plaque progression and rupture and assist in diagnosis and intervention procedures. This represents a new direction of research. Further investigations using more patient follow-up data are warranted. PMID:24669780

  1. Bacterial sex in dental plaque

    PubMed Central

    Olsen, Ingar; Tribble, Gena D.; Fiehn, Nils-Erik; Wang, Bing-Yan

    2013-01-01

    Genes are transferred between bacteria in dental plaque by transduction, conjugation, and transformation. Membrane vesicles can also provide a mechanism for horizontal gene transfer. DNA transfer is considered bacterial sex, but the transfer is not parallel to processes that we associate with sex in higher organisms. Several examples of bacterial gene transfer in the oral cavity are given in this review. How frequently this occurs in dental plaque is not clear, but evidence suggests that it affects a number of the major genera present. It has been estimated that new sequences in genomes established through horizontal gene transfer can constitute up to 30% of bacterial genomes. Gene transfer can be both inter- and intrageneric, and it can also affect transient organisms. The transferred DNA can be integrated or recombined in the recipient's chromosome or remain as an extrachromosomal inheritable element. This can make dental plaque a reservoir for antimicrobial resistance genes. The ability to transfer DNA is important for bacteria, making them better adapted to the harsh environment of the human mouth, and promoting their survival, virulence, and pathogenicity. PMID:23741559

  2. The riddle of Randall's plaques.

    PubMed

    Prien, E L

    1975-10-01

    Randall described a pre-calculus lesion of the renal papilla in the 1930s and this was substantiated by others during the next decade and then largely ignored. This insignificant subepithelial calcification of the renal papilla. Randall's plaque type I, becomes the nucleus of at least 15% of calcium oxalate calculi, as demonstrated by apatite nuclei existing in papillary depression on the external stone surface. Cross section study of the stone demonstrates the peripheral nucleus with eccentric lamination postulating a mural origin. Contrariwise, study of the stone developing upon a nucleus originating in the papillary ducts (without producing obstruction) or out in the calix demonstrates a central nucleus surrounded by concentric laminations or lack of a mural origin, the more common type of calcium oxalate stone structure. Obstruction of the papillary ducts by hyperexcretion of stone salt may result in anemic infarction and sloughing of the apex of the papilla. Data concerning the prevalence of Randall's plaques in the population have been reviewed. Evidence of the incidence of calcium oxalate calculi that have developed upon Randall's plaques has been presented. A plea for further study of the pathology of the renal papilla has been voiced. PMID:1235369

  3. Correlation of plasma soluble cluster of differentiation 40 ligand, alpha fetoprotein A, and pregnancy-associated plasma protein A with carotid plaque in patients with ischemic stroke.

    PubMed

    Wang, Y J; Gong, Z Q; Bi, X M; Li, Y L

    2015-01-01

    This study investigated the correlation of plama levels of inflammatory biomarkers [soluble cluster of differentiation 40 ligand (sCD40L), alpha fetoprotein A (fetuin-A), and pregnancy-associated protein A (PAPP-A)] with carotid plaque in patients with acute ischemic stroke. After undergoing color Doppler ultrasonography of the bilateral carotid arteries, 200 patients with acute ischemic stroke were grouped into plaque and non-plaque groups. The plaque group was further divided into stable and unstable plaque sub-groups by carotid plaque stability. Inter-group and -subgroup comparisons included demographic characteristics, current condition and medical history, and clinical laboratory and plama inflammatory biomarker data, and logistic regression explored the correlations between plama inflammatory biomarker levels and carotid plaques. Significantly higher sCD40L and fetuin-A levels were found in the plaque group than in the non-plaque group (all P < 0.05), with odds ratios (plaque vs non-plaque) of 6.372 and 4.101, respectively. Increased plama inflammatory biomarker levels were accompanied by a high risk of carotid plaque formation. Similarly, significantly higher plama sCD40L and PAPP-A levels were found in the unstable plaque subgroup than in the stable plaque subgroup (all P < 0.05), and the odds ratios (unstable vs stable) were 5.290 and 4.125, respectively. Increased plama inflammatory biomarker levels were accompanied by a high risk of carotid plaque instability. The study findings showed that plasma sCD40L, fetuin-A, and PAPP-A levels are associated with carotid plaque formation and instability. Fetuin-A and sCD40L might be predictors of carotid plaque formation, while PAPP-A and sCD40L might be predictors of carotid plaque instability. PMID:26214492

  4. Surgical Strategies for Acutely Ruptured Arteriovenous Malformations.

    PubMed

    Martinez, Jaime L; Macdonald, R Loch

    2015-11-01

    Brain arteriovenous malformations (AVMs) are focal neurovascular lesions consisting of abnormal fistulous connections between the arterial and venous systems with no interposed capillaries. This arrangement creates a high-flow circulatory shunt with hemorrhagic risk and hemodynamic abnormalities. While most AVMs are asymptomatic, they may cause severe neurological complications and death. Each AVM carries an annual rupture risk of 2-4%. Intracranial hemorrhage due to AVM rupture is the most common initial manifestation (up to 70% of presentations), and it carries significant morbidity and mortality. This complication is particularly important in the young and otherwise healthy population, in whom AVMs cause up to one-third of all hemorrhagic strokes. A previous rupture is the single most important independent predictor of future hemorrhage. Current treatment modalities for AVM are microsurgery, endovascular embolization, and radiosurgery. In acutely ruptured AVMs, early microsurgical excision is usually avoided. The standard is to wait at least 4 weeks to allow for patient recovery, hematoma liquefaction, and inflammatory reactions to subside. Exceptions to this rule are small, superficial, low-grade AVMs with elucidated angioarchitecture, for which early simultaneous hematoma evacuation and AVM excision is feasible. Emergent hematoma evacuation with delayed AVM excision (unless, as mentioned, the AVM is low grade) is recommended in patients with a decreased level of consciousness due to intracranial hemorrhage, posterior fossa or temporal lobe hematoma of >30 ml, or hemispheric hematoma of >60 ml. The applicability of endovascular techniques for acutely ruptured AVMs is not clear, but feasible options, until a definitive treatment is determined, include occluding intranidal and distal flow-related aneurysms and 'sealing' any rupture site or focal angioarchitectural weakness when one can be clearly identified and safely accessed. Radiosurgery is not performed in acutely ruptured AVMs because its therapeutic effects occur in a delayed fashion. PMID:26587641

  5. Partial rupture of the distal biceps tendon.

    PubMed

    Dürr, H R; Stäbler, A; Pfahler, M; Matzko, M; Refior, H J

    2000-05-01

    Partial rupture of the distal biceps tendon is a relatively rare event, and various degrees of partial tendon tears have been reported. In the current study four patients with partial atraumatic distal biceps tendon tears (mean age, 59 years; range, 40-82 years) are reported. In all four patients, a common clinical pattern emerged. Pain at the insertion of the distal biceps tendon in the radius unrelated to any traumatic event was the main symptom. In all patients the diagnosis was based on magnetic resonance imaging or computed tomography imaging. In three of four patients the partial rupture of the tendon caused a significant bursalike lesion. The typical appearance was a partially ruptured biceps tendon, with contrast enhancement signaling the degree of degeneration, tenosynovitis, and soft tissue swelling extending along the tendon semicircular to the proximal radius. In three patients, conservative treatment was successful. Only one patient needed surgery, with reinsertion of the tendon resulting in total functional recovery. PMID:10818980

  6. Computational stress analysis of atherosclerotic plaques in ApoE knockout mice.

    PubMed

    Vengrenyuk, Yuliya; Kaplan, Theodore J; Cardoso, Luis; Randolph, Gwendalyn J; Weinbaum, Sheldon

    2010-03-01

    The aortic sinus lesions of apolipoprotein E knockout (ApoE KO) mice seldom show any signs of fibrous cap disruption, whereas cap ruptures have been recently reported in the proximal part of their brachiocephalic arteries (BCA). We use histology based finite element analysis to evaluate peak circumferential stresses in aortic and BCA lesions from six 42-56 week-old fat-fed ApoE KO mice. This analysis is able to both explain the greater stability of aortic lesions in mice and provide new insight into the BCA lesion as a model for the stability of human lesions with and without microcalcifications in their fibrous caps. The predicted average peak stress in fibrous caps of aortic lesions of 205.8 kPa is significantly lower than the average value of maximum stresses of 568.8 kPa in BCA caps. The aortic plaque stresses only slightly depend on the cap thickness, while BCA lesions demonstrate an exponential growth of peak cap stresses with decreasing cap thickness similar to human vulnerable plaques. Murine BCA ruptured lesions with mean cap thickness of 2 microm show stresses approximately 1400 kPa, three times higher than human ruptured plaques with a mean cap thickness of 23 microm without microcalcifications in the cap, but nearly identical to the peak stress around an elongated microcalcification with aspect ratio 2 in a human thin cap approximately 50 microm thick. We predict biomechanical stress patterns in mouse BCA close to human vulnerable plaques without microcalcification in the cap, while aortic lesions show stress tendency similar to stable lesions in human. PMID:20336835

  7. The relevance of Randall's plaques

    PubMed Central

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

    2014-01-01

    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

  8. Shear wave elastography plaque characterization with mechanical testing validation: a phantom study

    NASA Astrophysics Data System (ADS)

    Widman, E.; Maksuti, E.; Larsson, D.; Urban, M. W.; Bjällmark, A.; Larsson, M.

    2015-04-01

    Determining plaque vulnerability is critical when selecting the most suitable treatment for patients with atherosclerotic plaque. Currently, clinical non-invasive ultrasound-based methods for plaque characterization are limited to visual assessment of plaque morphology and new quantitative methods are needed. In this study, shear wave elastography (SWE) was used to characterize hard and soft plaque mimicking inclusions in six common carotid artery phantoms by using phase velocity analysis in static and dynamic environments. The results were validated with mechanical tensile testing. In the static environment, SWE measured a mean shear modulus of 5.8? ± ?0.3?kPa and 106.2? ± ?17.2?kPa versus 3.3? ± ?0.5?kPa and 98.3? ± ?3.4?kPa measured by mechanical testing in the soft and hard plaques respectively. Furthermore, it was possible to measure the plaques’ shear moduli throughout a simulated cardiac cycle. The results show good agreement between SWE and mechanical testing and indicate the possibility for in vivo arterial plaque characterization using SWE.

  9. Three-Dimensional Carotid Plaque MR Imaging.

    PubMed

    Yuan, Chun; Parker, Dennis L

    2016-02-01

    There has been significant progress made in 3-dimensional (3D) carotid plaque MR imaging techniques in recent years. Three-dimensional plaque imaging clearly represents the future in clinical use. With effective flow-suppression techniques, choices of different contrast weighting acquisitions, and time-efficient imaging approaches, 3D plaque imaging offers flexible imaging plane and view angle analysis, large coverage, multivascular beds capability, and even can be used in fast screening. PMID:26610656

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  11. Blunt traumatic pericardial rupture.

    PubMed Central

    Levine, A J; Collins, F J

    1995-01-01

    A 28-year-old man presented with left chest, head and limb injuries following a road traffic accident (RTA). Increasing haemodynamic instability necessitated an emergency left thoracotomy at which a complete rupture of the pericardium and herniation of the heart was found. After repair, the patient made an uneventful post-operative recovery. The aetiology, investigation and management of this rare injury is discussed. Images Fig. 1 PMID:7640832

  12. Iatrogenic tracheobronchial rupture

    PubMed Central

    Paraschiv, M

    2014-01-01

    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

  13. Plaquing procedure for infectious hematopoietic necrosis virus

    USGS Publications Warehouse

    Burke, J.A.; Mulcahy, D.

    1980-01-01

    A single overlay plaque assay was designed and evaluated for infectious hematopoietic necrosis virus. Epithelioma papillosum carpio cells were grown in normal atmosphere with tris(hydroxymethyl)aminomethane- or HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid)-buffered media. Plaques were larger and formed more quickly on 1- to 3-day-old cell monolayers than on older monolayers. Cell culture medium with a 10% addition of fetal calf serum (MEM 10) or without serum (MEM 0) were the most efficient virus diluents. Dilution with phosphate-buffered saline, saline, normal broth, or deionized water reduced plaque numbers. Variations in the pH (7.0 to 8.0) of a MEM 0 diluent did not affect plaque numbers. Increasing the volume of viral inoculum above 0.15 ml (15- by 60-mm plate) decreased plaquing efficiency. Significantly more plaques occurred under gum tragacanth and methylcellulose than under agar or agarose overlays. Varying the pH (6.8 to 7.4) of methylcellulose overlays did not significantly change plaque numbers. More plaques formed under the thicker overlays of both methylcellulose and gum tragacanth. Tris(hydroxymethyl)aminomethane and HEPES performed equally well, buffering either medium or overlay. Plaque numbers were reduced when cells were rinsed after virus adsorption or less than 1 h was allowed for adsorption. Variation in adsorption time between 60 and 180 min did not change plaque numbers. The mean plaque formation time was 7 days at 16 degrees C. The viral dose response was linear when the standardized assay was used.

  14. Supplementary taurine may stabilize atheromatous plaque by antagonizing the activation of metalloproteinases by hypochlorous acid.

    PubMed

    McCarty, Mark F

    2004-01-01

    The rupture of atherosclerotic plaque, responsible for triggering the majority of myocardial infarctions, presumably requires proteolysis of collagen fibers and other protein components of the intercellular matrix. This is achieved by activated matrix metalloproteases (MMPs) secreted by intimal macrophages and foam cells. MMPs are synthesized as inactive pro-enzymes in which coordinate binding of the thiol group of a key cysteine residue to the active-site zinc atom blocks proteolytic activity. Physiological activation of MMPs is mediated, in large measure, by phagocyte-derived hypochlorous acid (HOCL), which can oxidize the zinc-bound thiol to sulfinic acid, thus freeing the active-site zinc. HOCL also encourages proteolysis of ground substance by inactivating proteins such as TIMP-1 that are physiological inhibitors of MMPs. In vivo, the unrestrained oxidant activity of HOCL is opposed by taurine, which reacts spontaneously with HOCL to generate taurine chloramine, much more stable than HOCL. Taurine chloramine has less impact than HOCL on MMP activation, and does not impair the activity of TIMP-1. Since tissue levels of taurine can be boosted via supplementation, taurine may thus have potential for stabilizing plaque and thereby warding off infarction--an effect that should be reinforced by taurine's platelet-stabilizing activity. In light of recent epidemiological evidence that increased expression of myeloperoxidase - the enzyme which generates HOCL--is an important risk factor for coronary disease, supplemental taurine may indeed have broader utility for suppressing both the genesis and the rupture of atherosclerotic plaque. PMID:15288359

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

    NASA Astrophysics Data System (ADS)

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

    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.

  16. Advanced MRI for carotid plaque imaging.

    PubMed

    Singh, Navneet; Moody, Alan R; Roifman, Idan; Bluemke, David A; Zavodni, Anna E H

    2016-01-01

    Atherosclerosis is the ubiquitous underling pathological process that manifests in heart attack and stroke, cumulating in the death of one in three North American adults. High-resolution magnetic resonance imaging (MRI) is able to delineate atherosclerotic plaque components and total plaque burden within the carotid arteries. Using dedicated hardware, high resolution images can be obtained. Combining pre- and post-contrast T1, T2, proton-density, and magnetization-prepared rapid acquisition gradient echo weighted fat-saturation imaging, plaque components can be defined. Post-processing software allows for semi- and fully automated quantitative analysis. Imaging correlation with surgical specimens suggests that this technique accurately differentiates plaque features. Total plaque burden and specific plaque components such as a thin fibrous cap, large fatty or necrotic core and intraplaque hemorrhage are accepted markers of neuroischemic events. Given the systemic nature of atherosclerosis, emerging science suggests that the presence of carotid plaque is also an indicator of coronary artery plaque burden, although the preliminary data primarily involves patients with stable coronary disease. While the availability and cost-effectiveness of MRI will ultimately be important determinants of whether carotid MRI is adopted clinically in cardiovascular risk assessment, the high accuracy and reliability of this technique suggests that it has potential as an imaging biomarker of future risk. PMID:26293362

  17. Migration of blood cells to β-amyloid plaques in Alzheimer's disease.

    PubMed

    Hohsfield, Lindsay A; Humpel, Christian

    2015-05-01

    Alzheimer's disease (AD) is a neurodegenerative disease that leads to the progressive deterioration of cognitive and memory functions. The deposition of extracellular beta-amyloid (Aβ) senile plaques and intracellular tau neurofibrillary tangles are considered the cardinal pathological hallmarks of AD, however, accumulating evidence indicates that immune cells may also play an important role in disease pathogenesis. Among these immune cells, blood-derived cells and their infiltration into the CNS towards Aβ plaques have been implicated in therapeutic strategies against AD. Here, we review the current literature on blood cell migration into the AD brain and the important players involved in this selective migration towards Aβ plaques. PMID:25752742

  18. Spectroscopic photoacoustic imaging of lipid-rich plaques in the human aorta in the 740 to 1400 nm wavelength range

    NASA Astrophysics Data System (ADS)

    Allen, Thomas J.; Hall, Andrew; Dhillon, Amar P.; Owen, James S.; Beard, Paul C.

    2012-06-01

    Spectroscopic photoacoustic imaging has the potential to discriminate between normal and lipid-rich atheromatous areas of arterial tissue by exploiting the differences in the absorption spectra of lipids and normal arterial tissue in the 740 to 1400 nm wavelength range. Identification of regions of high lipid concentration would be useful to identify plaques that are likely to rupture (vulnerable plaques). To demonstrate the feasibility of visualizing lipid-rich plaques, samples of human aortas were imaged in forward mode, at wavelengths of 970 and 1210 nm. It was shown that the structure of the arterial wall and the boundaries of lipid-rich plaques obtained from the photoacoustic images were in good agreement with histology. The presence of lipids was also confirmed by comparing the photoacoustic spectra (740 to 1400 nm) obtained in a region within the plaque to the spectral signature of lipids. Furthermore, a lipid-rich plaque was successfully imaged while illuminating the sample through 2.8 mm of blood demonstrating the possibility of implementing the photoacoustic technique in vivo.

  19. Modeling rupture segmentations on the Cascadia megathrust

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  20. Plaque and arterial vulnerability investigation in a three-layer atherosclerotic human coronary artery using computational fluid-structure interaction method

    NASA Astrophysics Data System (ADS)

    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza

    2014-08-01

    Coronary artery disease is the common form of cardiovascular diseases and known to be the main reason of deaths in the world. Fluid-Structure Interaction (FSI) simulations can be employed to assess the interactions of artery/plaque and blood to provide a more precise anticipation for rupture of arterial tissue layers and plaque tissues inside an atherosclerotic artery. To date, the arterial tissue in computational FSI simulations has been considered as a one-layer structure. However, a single layer assumption might have deeply bounded the results and, consequently, more computational simulation is needed by considering the arterial tissue as a three-layer structure. In this study, a three-dimensional computational FSI model of an atherosclerotic artery with a three-layer structure and different plaque types was established to perform a more accurate arterial wall/plaque tissue vulnerability assessment. The hyperelastic material coefficients of arterial layers were calculated and implemented in the computational model. The fully coupled fluid and structure models were solved using the explicit dynamics finite element code LS-DYNA. The results revealed the significant role of plaque types in the normal and shear stresses induced within the arterial tissue layers. The highest von Mises and shear stresses were observed on the stiffest calcified plaque with 3.59 and 3.27 MPa, while the lowest von Mises and shear stresses were seen on the hypocellular plaque with 1.15 and 0.63 MPa, respectively. Regardless of plaque types, the media and adventitia layers were played protective roles by displaying less stress on their wall, whilst the intima layer was at a high risk of rupture. The findings of this study have implications not only for determining the most vulnerable arterial layer/plaque tissue inside an atherosclerotic coronary artery but also for balloon-angioplasty, stenting, and bypass surgeries.

  1. Insights on atherosclerosis by non-invasive assessment of wall stress and arterial morphology along the length of human coronary plaques.

    PubMed

    Katranas, Sotirios A; Antoniadis, Antonios P; Kelekis, Anastasios L; Giannoglou, George D

    2015-12-01

    Wall stress (WS) is associated with high arterial pressure and affects the localization of atherosclerotic lesions. We sought to non-invasively investigate the distribution of WS along the length of human coronary arteries and investigate its potential effect on atherosclerosis in association with vascular stiffness, local arterial curvature and plaque volume. We reconstructed three-dimensionally 28 coronary arteries from 22 subjects who had undergone coronary computed tomography angiography. Coronary arteries were divided in 2 mm-long segments. WS, vascular stiffness, plaque volume and curvature were calculated in each segment using computational fluid dynamics and morphology measurements. Plaque segments exhibited lower WS compared to their adjacent normal segments. Within plaques, WS was lower in the mid plaque portion compared to the upstream portion. Plaque volume was higher in the mid plaque portion compared to upstream and downstream portions. Low WS was associated with high curvature and both low WS and high curvature were associated with increased plaque volume. The current study demonstrates that WS and plaque volume are not uniform in the longitudinal axis of human coronary plaque. Calculation of WS could serve as a surrogate for the localization of plaque development and the identification of plaques at a more advanced stage of progression. PMID:26255177

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

    PubMed Central

    2011-01-01

    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

  3. Ruptured tubal molar pregnancy.

    PubMed

    Yakasai, I A; Adamu, N; Galadanchi, H S

    2012-01-01

    Molar pregnancies in most instances develop within the uterine cavity, but may occur at any site. Ectopic molar pregnancy is a rare event. The objective of this study was to present a case of ruptured tubal molar gestation, discuss its clinical features and ways to improve diagnostic accuracy. A 35-year-old woman presented with features suggestive of ruptured tubal ectopic pregnancy. There was neither any evidence at the time of presentation to suspect a molar gestation, nor ? human chorionic gonadotrophin (?hCG) hormone estimation was done, but only a clearview pregnancy test was carried out. She had total left salpingectomy and histological evaluation of the specimen revealed complete hydatidiform mole. The hCG level normalized within 3 weeks of follow-up. Clinical features of ectopic molar pregnancy may be indistinguishable from non-molar ectopic pregnancy. We recommend ?hCG estimation as well as histological examination of the surgical specimen for all patients coming with features suggestive of ectopic pregnancy. PMID:23238205

  4. Ruptured Spleen as a Differential Diagnosis in Ruptured Tubal Pregnancy

    PubMed Central

    Weekes, Leroy R.

    1984-01-01

    Two cases of traumatic biphasic or secondary splenic rupture are presented to demonstrate the clinical picture of an entity the obstetrician-gynecologist will be encountering more commonly in the future. The signs and symptoms of this condition figured prominently in the differential diagnosis of ruptured tubal pregnancy. PMID:6737489

  5. Clinical Perspective of Carotid Plaque Imaging.

    PubMed

    Bonati, Leo H; Nederkoorn, Paul J

    2016-02-01

    At present, patients with carotid disease are selected for invasive recanalization therapies mainly based on the degree of luminal narrowing and the presence or absence of recent ischemic symptoms. A more sophisticated risk model takes into account other clinical variables, such as age, sex, and the type of recent symptoms, as well as presence of ulcerated plaque. A growing body of evidence shows that noninvasive imaging of the carotid plaque by various methods reliably identifies structural correlates of plaque vulnerability, which are associated with an increased risk of cerebrovascular events. PMID:26610668

  6. Wrapped Wire Detects Rupture Of Pressure Vessel

    NASA Technical Reports Server (NTRS)

    Hunt, James B.

    1990-01-01

    Simple, inexpensive technique helps protect against damage caused by continuing operation of equipment after rupture or burnout of pressure vessel. Wire wrapped over area on outside of vessel where breakthrough most likely. If wall breaks or burns, so does wire. Current passing through wire ceases, triggering cutoff mechanism stopping flow in vessel to prevent further damage. Applied in other situations in which pipes or vessels fail due to overpressure, overheating, or corrosion.

  7. The prevention and regression of atherosclerotic plaques: emerging treatments

    PubMed Central

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

    2012-01-01

    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

  8. Spontaneous rupture on irregular faults

    NASA Astrophysics Data System (ADS)

    Liu, C.

    2014-12-01

    It is now know (e.g. Robinson et al., 2006) that when ruptures propagate around bends, the rupture velocity decrease. In the extreme case, a large bend in the fault can stop the rupture. We develop a 2-D finite difference method to simulate spontaneous dynamic rupture on irregular faults. This method is based on a second order leap-frog finite difference scheme on a uniform mesh of triangles. A relaxation method is used to generate an irregular fault geometry-conforming mesh from the uniform mesh. Through this numerical coordinate mapping, the elastic wave equations are transformed and solved in a curvilinear coordinate system. Extensive numerical experiments using the linear slip-weakening law will be shown to demonstrate the effect of fault geometry on rupture properties. A long term goal is to simulate the strong ground motion near the vicinity of bends, jogs, etc.

  9. Ruptured thought: rupture as a critical attitude to nursing research.

    PubMed

    Beedholm, Kirsten; Lomborg, Kirsten; Frederiksen, Kirsten

    2014-04-01

    In this paper, we introduce the notion of ‘rupture’ from the French philosopher Michel Foucault, whose studies of discourse and governmentality have become prominent within nursing research during the last 25 years. We argue that a rupture perspective can be helpful for identifying and maintaining a critical potential within nursing research. The paper begins by introducing rupture as an inheritance from the French epistemological tradition. It then describes how rupture appears in Foucault's works, as both an overall philosophical approach and as an analytic tool in his historical studies. Two examples of analytical applications of rupture are elaborated. In the first example, rupture has inspired us to make an effort to seek alternatives to mainstream conceptions of the phenomenon under study. In the second example, inspired by Foucault's work on discontinuity, we construct a framework for historical epochs in nursing history. The paper concludes by discussing the potential of the notion of rupture as a response to the methodological concerns regarding the use of Foucault-inspired discourse analysis within nursing research. We agree with the critique of Cheek that the critical potential of discourse analysis is at risk of being undermined by research that tends to convert the approach into a fixed method. PMID:24741691

  10. A new inexpensive customized plaque for choroidal melanoma iodine-125 plaque therapy.

    PubMed

    Vine, A K; Tenhaken, R K; Diaz, R F; Maxson, B B; Lichter, A S

    1989-04-01

    The authors have developed a new inexpensive precious metal alloy plaque for use in customized iodine-125 plaque therapy. Each plaque is formed from two flat circular gold/palladium foils which are used in dental crown work. Using a simple manual mechanism, the two forms are stamped over a customized acrylic die shaped to the dimensions of the tumor base plus a 2-mm margin. Completed plaques consist of a back wall, a 2-mm side wall, and a 1.5-mm wide lip with holes for suture placement. Advantages include: simple construction from inexpensive components, customized shape, and iodine seeds that are readily visible on plane radiographs. PMID:2726186

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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. μCT 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.

  12. Utility of Combining PET and MR Imaging of Carotid Plaque.

    PubMed

    Vesey, Alex T; Dweck, Marc R; Fayad, Zahi A

    2016-02-01

    By harnessing the versatility and soft tissue imaging capabilities of MR imaging alongside the unmatched sensitivity and biomolecular flexibility of PET, the potential to provide detailed multiparametric plaque characterization in the carotid arteries is clear. The ability to acquire simultaneous, and dynamic multimodal data is perhaps PET/MR's greatest strength that will be of major interest to researchers investigating carotid and coronary atherosclerosis alike. This review summarizes the current status of dedicated hybrid PET/MR imaging; to crystallize the rationale for and advantages of this technique with respect to carotid atherosclerosis; and to discuss current limitations, challenges, and future directions. PMID:26610660

  13. Transient gravity perturbations induced by earthquake rupture

    NASA Astrophysics Data System (ADS)

    Harms, J.; Ampuero, J.-P.; Barsuglia, M.; Chassande-Mottin, E.; Montagner, J.-P.; Somala, S. N.; Whiting, B. F.

    2015-06-01

    The static and transient deformations produced by earthquakes cause density perturbations which, in turn, generate immediate, long-range perturbations of the Earth's gravity field. Here, an analytical solution is derived for gravity perturbations produced by a point double-couple source in homogeneous, infinite, non-self-gravitating elastic media. The solution features transient gravity perturbations that occur at any distance from the source between the rupture onset time and the arrival time of seismic P waves, which are of potential interest for real-time earthquake source studies and early warning. An analytical solution for such prompt gravity perturbations is presented in compact form. We show that it approximates adequately the prompt gravity perturbations generated by strike-slip and dip-slip finite fault ruptures in a half-space obtained by numerical simulations based on the spectral element method. Based on the analytical solution, we estimate that the observability of prompt gravity perturbations within 10 s after rupture onset by current instruments is severely challenged by the background microseism noise but may be achieved by high-precision gravity strainmeters currently under development. Our analytical results facilitate parametric studies of the expected prompt gravity signals that could be recorded by gravity strainmeters.

  14. Improved treatment planning for COMS eye plaques

    SciTech Connect

    Astrahan, Melvin A. . E-mail: astrahan@usc.edu

    2005-03-15

    Purpose: A recent reanalysis of the Collaborative Ocular Melanoma Study (COMS) medium tumor trial concluded that incorporating factors to account for anisotropy, line source approximation, the gold plaque, and attenuation in the Silastic seed carrier into the dose calculations resulted in a significant and consistent reduction of calculated doses to structures of interest within the eye. The authors concluded that future eye plaque dosimetry should be 'performed using the most up-to-date parameters available.' The reason these factors are important is attributable to the low energy {sup 125}I radiation (approximately 28 keV) that is primarily absorbed by the photoelectric process. Photoelectric absorption is quite dependent on the atomic composition of the absorbing material. Being 40% silicon by weight, the effective atomic number of Silastic is significantly greater than that of water. Although the AAPM TG43 brachytherapy formalism inherently addresses the issues of source anisotropy and geometry, its parameter that accounts for scatter and attenuation, the radial dose function g(r), assumes that the source is immersed in infinite homogeneous water. In this work, factors are proposed for {sup 125}I that correct for attenuation in the Silastic carrier and scatter deficits resulting from the gold plaque and nearby air. The implications of using {sup 103}Pd seeds in COMS plaques are also discussed. Methods and materials: An existing TG43-based ophthalmic plaque planning system was modified to incorporate additional scatter and attenuation correction factors that better account for the path length of primary radiation in the Silastic seed carrier and the distance between the dose calculation point and the eye-air interface. Results: Compared with homogeneous water, the dose-modifying effects of the Silastic and gold are greatest near the plaque surface and immediately adjacent to the plaque, while being least near the center of the eye. The calculated dose distribution surrounding a single {sup 125}I seed centered in a COMS 20 mm plaque was found to be consistent with previously published examples that used thermoluminescent dosimetry measurements and Monte Carlo methods. For fully loaded 12 and 20 mm plaques, calculated dose to critical ocular structures ranged from 16%-50% less than would have been reported using the standard COMS dose calculation protocol. Conclusions: Treatment planning for COMS eye plaques that accurately accounts for the presence of the gold, Silastic and extraocular air is both possible and practical.

  15. Aneurysm flow characteristics in realistic carotid artery aneurysm models induced by proximal virtual stenotic plaques: a computational hemodynamics study

    NASA Astrophysics Data System (ADS)

    Castro, Marcelo A.; Peloc, Nora L.; Chien, Aichi; Goldberg, Ezequiel; Putman, Christopher M.; Cebral, Juan R.

    2015-03-01

    Cerebral aneurysms may rarely coexist with a proximal artery stenosis. In that small percent of patients, such coexistence poses a challenge for interventional neuroradiologists and neurosurgeons to make the best treatment decision. According to previous studies, the incidence of cerebral aneurysms in patients with internal carotid artery stenosis is no greater than five percent, where the aneurysm is usually incidentally detected, being about two percent for aneurysms and stenoses in the same cerebral circulation. Those cases pose a difficult management decision for the physician. Case reports showed patients who died due to aneurysm rupture months after endarterectomy but before aneurysm clipping, while others did not show any change in the aneurysm after plaque removal, having optimum outcome after aneurysm coiling. The aim of this study is to investigate the intra-aneurysmal hemodynamic changes before and after treatment of stenotic plaque. Virtually created moderate stenoses in vascular models of internal carotid artery aneurysm patients were considered in a number of cases reconstructed from three dimensional rotational angiography images. The strategy to create those plaques was based on parameters analyzed in a previous work where idealized models were considered, including relative distance and stenosis grade. Ipsilateral and contralateral plaques were modeled. Wall shear stress and velocity pattern were computed from finite element pulsatile blood flow simulations. The results may suggest that wall shear stress changes depend on relative angular position between the aneurysm and the plaque.

  16. Cholesterol crystals piercing the arterial plaque and intima trigger local and systemic inflammation.

    PubMed

    Abela, George S

    2010-01-01

    The response to arterial wall injury is an inflammatory process, which over time becomes integral to the development of atherosclerosis and subsequent plaque instability. However, the underlying injurious agent, critical to this process, has not received much attention. In this review, a model of plaque rupture is hypothesized with two stages of inflammatory activity. In stage I (cholesterol crystal-induced cell injury and apoptosis), intracellular cholesterol crystals induce foam cell apoptosis, setting up a vicious cycle by signaling more macrophages, resulting in accumulation of extra cellular lipids. This local inflammation eventually leads to the formation of a semi-liquid, lipid-rich necrotic core of a vulnerable plaque. In stage II (cholesterol crystal-induced arterial wall injury), the saturated lipid core is now primed for crystallization, which can manifest as a clinical syndrome with a systemic inflammation response. Cholesterol crystallization is the trigger that causes core expansion, leading to intimal injury. We recently demonstrated that when cholesterol crystallizes from a liquid to a solid state, it undergoes volume expansion, which can tear the plaque cap. This observation of cholesterol crystals perforating the cap and intimal surface was made in the plaques of patients who died with acute coronary syndrome. We have also demonstrated that several agents (ie, statins, aspirin, and ethanol) can dissolve cholesterol crystals and may be exerting their immediate benefits by this direct mechanism. Also, because recent studies have demonstrated that high-sensitivity C-reactive protein may be a reliable marker in selecting patients for statin therapy, it could reflect the presence of intimal injury by cholesterol crystals. This was demonstrated in an atherosclerotic rabbit model. Therefore, we propose that cholesterol crystallization could help explain in part both local and systemic inflammation associated with atherosclerosis. PMID:21122648

  17. Mechanical Interaction of an Expanding Coiled Stent with a Plaque-Containing Arterial Wall: A Finite Element Analysis.

    PubMed

    Welch, Tré R; Eberhart, Robert C; Banerjee, Subhash; Chuong, Cheng-Jen

    2016-03-01

    Wall injury is observed during stent expansion within atherosclerotic arteries, related in part to stimulation of the inflammatory process. Wall stress and strain induced by stent expansion can be closely examined by finite element analysis (FEA), thus shedding light on procedure-induced sources of inflammation. The purpose of this work was to use FEA to examine the interaction of a coiled polymer stent with a plaque-containing arterial wall during stent expansion. An asymmetric fibrotic plaque-containing arterial wall model was created from intravascular ultrasound (IVUS) images of a diseased artery. A 3D model for a coil stent at unexpanded state was generated in SolidWorks. They were imported into ANSYS for FEA of combined stent expansion and fibrotic plaque-distortion. We simulated the stent expansion in the plaqued lumen by increasing balloon pressure from 0 to 12 atm in 1 atm step. At increasing pressure, we examined how the expanding stent exerts forces on the fibrotic plaque and vascular wall components, and how the latter collectively resist and balance the expansive forces from the stent. Results show the expanding coiled stent creates high stresses within the plaque and the surrounding fibrotic capsule. Lower stresses were observed in adjacent medial and adventitial layers. High principal strains were observed in plaque and fibrotic capsule. The results suggest fibrotic capsule rupture might occur at localized regions. The FEA/IVUS method can be adapted for routine examination of the effects of the expansion of selected furled stents against IVUS-reconstructed diseased vessels, to improve stent deployment practices. PMID:26621671

  18. Morphometric analysis of the composition of coronary arterial plaques in isolated unstable angina pectoris with pain at rest.

    PubMed

    Kragel, A H; Reddy, S G; Wittes, J T; Roberts, W C

    1990-09-01

    Coronary artery plaque morphology was studied in 354 five-mm segments of the 4 major (left main, left anterior descending, left circumflex and right) epicardial coronary arteries in 10 patients with isolated unstable angina pectoris with pain at rest. The 4 major coronary arteries were sectioned at 5-mm intervals and a drawing of each of the resulting 354 Movat-stained histologic sections was analyzed using a computerized morphometry system. The major component of plaque was a combination of dense acellular and cellular fibrous tissue with much smaller portions of plaque being composed of pultaceous debris, calcium, foam cells with and without inflammatory infiltrates and inflammatory infiltrates without foam cells. There were no differences in plaque composition among any of the 4 major epicardial coronary arteries. Plaque composition varied as a function of the degree of luminal narrowing. Linear increases were observed in the mean percent of dense fibrous tissue (from 5 to 50%), calcific deposits (from 1 to 10%), pultaceous debris (from 0 to 10%) and inflammatory infiltrates without significant numbers of foam cells (from 0 to 5%), and a linear decrease was observed in the mean percent of cellular fibrous tissue (from 94 to 22%) in sections narrowed up to 25% to more than 95% in cross-sectional area. Multiluminal channels were seen in all 10 patients (28 [19%] of the 146 sections narrowed greater than 75% in cross-sectional area and in 36 [10%] of all 354 segments); occlusive thrombi in no patient; nonocclusive thrombi in 2 patients (1 section each of 2 arteries); plaque rupture in 2 patients (4 segments from 2 arteries); and plaque hemorrhages in 6 patients (11 sections from 10 arteries). PMID:2392977

  19. Chemical agents for the control of plaque and plaque microflora: an overview.

    PubMed

    Gaffar, A; Afflitto, J; Nabi, N

    1997-10-01

    This presentation provides an overview of the technologies available for the chemical control of plaque. It is generally accepted that the formation of dental plaque at the interfaces of tooth/gingiva is one of the major causes of gingival inflammation and dental caries. Several therapeutic approaches have been used to control dental plaque and supragingival infections. These include fluoride preparations such as stannous fluoride, oxygenating agents, anti-attachment agents, and cationic and non-cationic antibacterial agents. Among the fluoride preparations, stable stannous fluoride pastes and gels have been shown to reduce supragingival plaque, gingivitis, hypersensitivity and caries. The effect of the oxygenating agents on the supragingival plaque has been equivocal, but recent data indicate that a stable agent which provides sustained active oxygen release is effective in controlling plaque. A polymer, PVPA, which reduced attachment of bacteria to teeth was shown to significantly reduce plaque formation in humans. A new generation of antibacterials includes non-ionics such as triclosan, which in combination with a special polymer delivery system, has been shown to reduce plaque, gingivitis, supragingival calculus and dental caries in long-term studies conducted around the world. Unlike the first generation of agents, the triclosan/copolymer/sodium fluoride system is effective in long-term clinicals and does not cause staining of teeth, increase in calculus, or disturbance in the oral microbial ecology. PMID:9395116

  20. Amyloid Plaques in PSAPP Mice Bind Less Metal than Plaques in Human Alzheimer's Disease

    SciTech Connect

    Leskovjan, A.; Lanzirotti, A; Miller, L

    2009-01-01

    Amyloid beta (A{Beta}) is the primary component of Alzheimer's disease (AD) plaques, a key pathological feature of the disease. Metal ions of zinc (Zn), copper (Cu), iron (Fe), and calcium (Ca) are elevated in human amyloid plaques and are thought to be involved in neurodegeneration. Transgenic mouse models of AD also exhibit amyloid plaques, but fail to exhibit the high degree of neurodegeneration observed in humans. In this study, we imaged the Zn, Cu, Fe, and Ca ion distribution in the PSAPP transgenic mouse model representing end-stage AD (N = 6) using synchrotron X-ray fluorescence (XRF) microprobe. In order to account for differences in density in the plaques, the relative protein content was imaged with synchrotron Fourier transform infrared microspectroscopy (FTIRM) on the same samples. FTIRM results revealed a 61% increase in protein content in the plaques compared to the surrounding tissue. After normalizing to protein density, we found that the PSAPP plaques contained only a 29% increase in Zn and there was actually less Cu, Fe, and Ca in the plaque compared to the surrounding tissue. Since metal binding to A{beta} is thought to induce redox chemistry that is toxic to neurons, the reduced metal binding in PSAPP mice is consistent with the lack of neurodegeneration in these animals. These findings were in stark contrast to the high metal ion content observed in human AD plaques, further implicating the role of metal ions in human AD pathology.

  1. Carotid plaque assessment using fast 3D isotropic resolution black-blood MRI.

    PubMed

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

    2011-03-01

    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 (0.7×0.7×0.7 mm3) three-dimensional black-blood sequence (3D-MERGE) covering the entire cervical carotid arteries within 2 min 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 signal-to-noise ratio 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

  2. Functional expression of dental plaque microbiota

    PubMed Central

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

    2014-01-01

    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

  3. Effects of Mechanical Properties and Atherosclerotic Artery Size on Biomechanical Plaque Disruption - Mouse versus Human

    PubMed Central

    Riou, Laurent M.; Broisat, Alexis; Ghezzi, Catherine; Finet, Gérard; Rioufol, Gilles; Gharib, Ahmed M.; Pettigrew, Roderic I.; Ohayon, Jacques

    2015-01-01

    Mouse models of atherosclerosis are extensively being used to study the mechanisms of atherosclerotic plaque development and the results are frequently extrapolated to humans. However, major differences have been described between murine and human atherosclerotic lesions and the determination of similarities and differences between these species has been largely addressed recently. This study takes over and extends previous studies performed by our group and related to the biomechanical characterization of both mouse and human atherosclerotic lesions. Its main objective was to determine the distribution and amplitude of mechanical stresses including peak cap stress (PCS) in aortic vessels from atherosclerotic, apoE?/? mice in order to evaluate whether such biomechanical data would be in accordance with the previously suggested lack of plaque rupture in this model. Successful finite element analysis was performed from the zero-stress configuration of aortic arch sections and mainly indicated (1) the modest role of atherosclerotic lesions in the observed increase in residual parietal stresses in apoE?/? mouse vessels and (2) the low amplitude of murine PCS as compared to humans. Overall, the results from the present study support the hypothesis that murine biomechanical properties and artery size confer less propensity to rupture for mouse lesions in comparison with those of humans. PMID:24491495

  4. Regression of coronary artery disease: the role of plaque biology.

    PubMed

    Valle, B K; Valle, G A; Lemberg, L

    1995-11-01

    Research has lead to a better understanding of the pathophysiology and history of atherosclerotic heart disease, which has reached epidemic proportions in industrialized countries in this century. Atherosclerosis should be seen as a chronic, protracted process that encompasses complex and dynamic interactions between cellular, biochemical, and biophysical factors in the microcosmos of the arterial vessel wall and blood circulation. In this context, the ultimate consequences of this disease process, namely coronary artery disease, must be seen as the "tip of the iceberg." The most dramatic manifestation of coronary artery disease, the acute coronary syndrome, usually occurs as the result of different forces and factors, which lead to abrupt plaque disruption, rupture, and vessel thrombosis. In contrast, the genesis of this atherosclerotic lesion is a slow process. Despite considerable experimental clinical evidence accrued during the past decade, atherosclerosis remains a complex pathophysiological process that is not fully understood. It is clear, however, that the interaction between the cellular elements of the vessel wall and the circulation are the determinants of atheroma formation. In this regard, the vascular endothelium appears to play a pivotal role because of its strategic location and metabolic activity. Antilipidemic therapy influences the outcome of coronary disease through a variety of mechanisms, including direct and indirect effects on the endothelium. PMID:8556091

  5. 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

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

    2014-01-01

    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

  6. A Thoracotomy Approach for the Surgical Repair of a Left Ventricular Free Wall Rupture.

    PubMed

    DeCicco, Anthony E; Alaiti, M Amer; Ali, Jafer; Cohen, Jamie N; Deo, Salil V; Parikh, Sahil A; Park, Soon J

    2016-03-01

    In the current era of rapid culprit vessel revascularization in acute myocardial infarction, ventricular free wall rupture is becoming increasingly uncommon. In rare cases adherent pericardium may contain this rupture, creating a temporary stable pseudoaneurysm. With the aid of intraoperative pictures, we describe herein a left thoracotomy approach for the surgical correction of a left ventricular pseudoaneurysm secondary to free wall rupture. PMID:26897236

  7. Statistical segmentation of carotid plaque neovascularization

    NASA Astrophysics Data System (ADS)

    Akkus, Zeynettin; Bosch, Johan G.; Sánchez-Ferrero, Gonzalo V.; Carvalho, Diego D. B.; Renaud, Guillaume; van den Oord, Stijn C. H.; ten Kate, Gerrit L.; Schinkel, Arend F. L.; de Jong, Nico; van der Steen, Antonius F. W.

    2013-03-01

    In several studies, intraplaque neovascularization (IPN) has been linked with plaque vulnerability. The recent development of contrast enhanced ultrasound enables IPN detection, but an accurate quantification of IPN is a big challenge due to noise, motion, subtle contrast response, blooming of contrast and artifacts. We present an algorithm that automatically estimates the location and amount of contrast within the plaque over time. Plaque pixels are initially labeled through an iterative expectation-maximization (EM) algorithm. The used algorithm avoids several drawbacks of standard EM. It is capable of selecting the best number of components in an unsupervised way, based on a minimum message length criterion. Next, neighborhood information using a 5×5 kernel and spatiotemporal behavior are combined with the known characteristics of contrast spots in order to group components, identify artifacts and finalize the classification. Image sequences are divided into 3-seconds subgroups. A pixel is relabeled as an artifact if it is labeled as contrast for more than 1.5 seconds in at least two subgroups. For 10 plaques, automated segmentation results were validated with manual segmentation of contrast in 10 frames per clip. Average Dice index and area ratio were 0.73+/-0.1 (mean+/-SD) and 98.5+/-29.6 (%) respectively. Next, 45 atherosclerotic plaques were analyzed. Time integrated IPN surface area was calculated. Average area of IPN was 3.73+/-3.51 mm2. Average area of 45 plaques was 11.6+/-8.6 mm2. This method based on EM contrast segmentation provides a new way of IPN quantification.

  8. Association between Randall's Plaque and Calcifying Nanoparticles

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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.

  9. [Achilles tendon ruptures and tibialis anterior tendon ruptures].

    PubMed

    Pagenstert, G; Leumann, A; Frigg, A; Valderrabano, V

    2010-12-01

    Achilles tendon ruptures (ATR) are becoming the most frequent tendon rupture of the lower extremity, whereas less than 100 cases of tibialis anterior tendon ruptures (TATR) have been reported. Common in both tendons are the degenerative causes of ruptures in a susceptible tendon segment, whereas traumatic transections occur at each level. Triceps surae and tibialis anterior muscles are responsible for the main sagittal ankle range of motion and ruptures lead to a distinctive functional deficit. However, diagnosis is delayed in up to 25% of ATR and even more frequently in TATR. Early primary repair provides the best functional results. With progressive retraction and muscle atrophy delayed tendon reconstruction has less favourable functional results. But not all patients need full capacity, power and endurance of these muscles and non-surgical treatment should not be forgotten. Inactive patients with significant comorbidities and little disability should be informed that surgical treatment of TATR is complicated by high rates of rerupture and surgical treatment of ATR can result in wound healing problems rarely necessitating some kind of transplantation. PMID:21110002

  10. Integrated IVUS-OCT Imaging for Atherosclerotic Plaque Characterization

    PubMed Central

    Li, Xiang; Li, Jiawen; Jing, Joe; Ma, Teng; Liang, Shanshan; Zhang, Jun; Mohar, Dilbahar; Raney, Aidan; Mahon, Sari; Brenner, Matthew; Patel, Pranav; Shung, K. Kirk; Zhou, Qifa; Chen, Zhongping

    2014-01-01

    For the diagnosis of atherosclerosis, biomedical imaging techniques such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been developed. The combined use of IVUS and OCT is hypothesized to remarkably increase diagnostic accuracy of vulnerable plaques. We have developed an integrated IVUS-OCT imaging apparatus, which includes the integrated catheter, motor drive unit, and imaging system. The dual-function imaging catheter has the same diameter of current clinical standard. The imaging system is capable for simultaneous IVUS and OCT imaging in real time. Ex vivo and in vivo experiments on rabbits with atherosclerosis were conducted to demonstrate the feasibility and superiority of the integrated intravascular imaging modality. PMID:24771992

  11. Fault Branching and Rupture Directivity

    NASA Astrophysics Data System (ADS)

    Dmowska, R.; Rice, J. R.; Kame, N.

    2002-12-01

    Can the rupture directivity of past earthquakes be inferred from fault geometry? Nakata et al. [J. Geogr., 1998] propose to relate the observed surface branching of fault systems with directivity. Their work assumes that all branches are through acute angles in the direction of rupture propagation. However, in some observed cases rupture paths seem to branch through highly obtuse angles, as if to propagate ``backwards". Field examples of that are as follows: (1) Landers 1992. When crossing from the Johnson Valley to the Homestead Valley (HV) fault via the Kickapoo (Kp) fault, the rupture from Kp progressed not just forward onto the northern stretch of the HV fault, but also backwards, i.e., SSE along the HV [Sowers et al., 1994, Spotila and Sieh, 1995, Zachariasen and Sieh, 1995, Rockwell et al., 2000]. Measurements of surface slip along that backward branch, a prominent feature of 4 km length, show right-lateral slip, decreasing towards the SSE. (2) At a similar crossing from the HV to the Emerson (Em) fault, the rupture progressed backwards along different SSE splays of the Em fault [Zachariasen and Sieh, 1995]. (3). In crossing from the Em to Camp Rock (CR) fault, again, rupture went SSE on the CR fault. (4). Hector Mine 1999. The rupture originated on a buried fault without surface trace [Li et al., 2002; Hauksson et al., 2002] and progressed bilaterally south and north. In the south it met the Lavic Lake (LL) fault and progressed south on it, but also progressed backward, i.e. NNW, along the northern stretch of the LL fault. The angle between the buried fault and the northern LL fault is around -160o, and that NNW stretch extends around 15 km. The field examples with highly obtuse branch angles suggest that there may be no simple correlation between fault geometry and rupture directivity. We propose that an important distinction is whether those obtuse branches actually involved a rupture path which directly turned through the obtuse angle (while continuing also on the main fault), or rather involved arrest by a barrier on the original fault and jumping [Harris and Day, JGR, 1993] to a neighboring fault on which rupture propagated bilaterally to form what appears as a backward-branched structure. Our studies [Poliakov et al., JGR in press, 2002; Kame et al, EOS, 2002] of stress fields around a dynamically moving mode II crack tip show a clear tendency to branch from the straight path at high rupture speeds, but the stress fields never allow the rupture path to directly turn through highly obtuse angles, and hence that mechanism is unlikely. In contrast, study of fault maps in the vicinity of the Kp to HV fault transition [Sowers et al., 1994], discussed as case (1) above, strongly suggest that the large-angle branching occurred as a jump, which we propose as the likely general mechanism. Implications for the Nakata et al. [1998] aim of inferring rupture directivity from branch geometry is that this will be possible only when rather detailed characterization (by surface geology, seismic relocation, trapped waves) of fault connectivity can be carried out in the vicinity of the branching junction, to ascertain whether direct turning of the rupture path through an angle, or jumping and then propagating bilaterally, were involved in prior events. They have opposite implications for how we would associate past directivity with a (nominally) branched fault geometry.

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

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

    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 estimate fibrous cap thickness in NCFAs. Time-varying laser speckle images of 20 NCFAs are selected for analysis. Spatio-temporal intensity fluctuations are analyzed by exponential fitting of the windowed normalized cross-correlation of sequential laser speckle patterns to obtain the speckle decorrelation time constant, ?(?), as a function of distance ? from the source entry location. The distance, ??, at which ?(?) dropped to 65% of its maximum value is recorded. Diffusion theory and Monte Carlo models are utilized to estimate the maximum photon penetration depth, zmax(??), for a distance equal to ??, measured from LSI. Measurements of zmax(??) correlate well with histological measurements of fibrous cap thickness (R=0.78,p<0.0001), and paired t-tests show no significant difference between the groups (p=0.4). These results demonstrate that spatio-temporal LSI may allow the estimation of fibrous cap thickness in NCFAs, which is an important predictor of plaque stability.

  13. Plaque Imaging to Decide on Optimal Treatment: Medical Versus Carotid Endarterectomy Versus Carotid Artery Stenting.

    PubMed

    Sun, Jie; Hatsukami, Thomas S

    2016-02-01

    Many of the current guidelines for the management of carotid atherosclerosis are based on clinical trial findings published more than 2 decades ago. The lack of plaque information in clinical decision making represents a major shortcoming and highlights the need for contemporary trials based on characteristics of the atherosclerotic lesion itself, rather than luminal stenosis alone. This article summarizes the major dilemmas clinicians face in current practice, and discusses the rationale and evidence that plaque imaging may help to address these challenges and optimize the clinical management of carotid artery disease in the future. PMID:26610667

  14. Dobesilate in the treatment of plaque psoriasis.

    PubMed

    Cuevas, Pedro; Arrazola, Jose M

    2005-09-12

    Fibroblast growth factor (FGF)-mediated pathways participate in many of the cellular events implicated in the pathogenesis of psoriasis. Thus, targeting FGF signals may be potentially therapeutic in the treatment of psoriasis. We report for the first time on a 43-year-old man with chronic-type plaque psoriasis with a daily topical treatment of dobesilate, a new FGF inhibitor. As early as at day 14, the patient had cleared or achieved excellent improvement of psoriatic skin lesions. Topical dobesilate offers the potential for treatment of plaque psoriasis without atrophy or other local side effects associated with the use of topical corticosteroids. PMID:16183548

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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).

  16. Rapid Estimates of Rupture Extent for Large Earthquakes Using Aftershocks

    NASA Astrophysics Data System (ADS)

    Polet, J.; Thio, H. K.; Kremer, M.

    2009-12-01

    The spatial distribution of aftershocks is closely linked to the rupture extent of the mainshock that preceded them and a rapid analysis of aftershock patterns therefore has potential for use in near real-time estimates of earthquake impact. The correlation between aftershocks and slip distribution has frequently been used to estimate the fault dimensions of large historic earthquakes for which no, or insufficient, waveform data is available. With the advent of earthquake inversions that use seismic waveforms and geodetic data to constrain the slip distribution, the study of aftershocks has recently been largely focused on enhancing our understanding of the underlying mechanisms in a broader earthquake mechanics/dynamics framework. However, in a near real-time earthquake monitoring environment, in which aftershocks of large earthquakes are routinely detected and located, these data may also be effective in determining a fast estimate of the mainshock rupture area, which would aid in the rapid assessment of the impact of the earthquake. We have analyzed a considerable number of large recent earthquakes and their aftershock sequences and have developed an effective algorithm that determines the rupture extent of a mainshock from its aftershock distribution, in a fully automatic manner. The algorithm automatically removes outliers by spatial binning, and subsequently determines the best fitting “strike” of the rupture and its length by projecting the aftershock epicenters onto a set of lines that cross the mainshock epicenter with incremental azimuths. For strike-slip or large dip-slip events, for which the surface projection of the rupture is recti-linear, the calculated strike correlates well with the strike of the fault and the corresponding length, determined from the distribution of aftershocks projected onto the line, agrees well with the rupture length. In the case of a smaller dip-slip rupture with an aspect ratio closer to 1, the procedure gives a measure of the rupture extent and dimensions, but not necessarily the strike. We found that using standard earthquake catalogs, such as the National Earthquake Information Center catalog, we can constrain the rupture extent, rupture direction, and in many cases the type of faulting, of the mainshock with the aftershocks that occur within the first hour after the mainshock. However, this data may not be currently available in near real-time. Since our results show that these early aftershock locations may be used to estimate first order rupture parameters for large global earthquakes, the near real-time availability of these data would be useful for fast earthquake damage assessment.

  17. Rupture of the tracheobronchial tree.

    PubMed Central

    Roxburgh, J C

    1987-01-01

    Eleven cases of tracheobronchial rupture are described. Nine were the result of external non-penetrating trauma and all but three had other serious injuries. The remaining two were caused by endobronchial intubation. Of the cases caused by external injury, respiratory tract injury was confined to the cervical trachea in three. Two required tracheostomy and repair and the third was managed conservatively; all made satisfactory recoveries. Intrathoracic rupture was recognised on or soon after admission in three cases. One patient died of uncontrollable pulmonary haemorrhage before he could be operated on; immediate repair gave good long term results in the other two. In three cases rupture of the main bronchus was not recognised until complete obstruction developed three, five, and 12 weeks after the accidents. The strictures were resected and the lung re-expanded. Robertshaw endobronchial tubes ruptured the left main bronchus in two patients undergoing oesophageal surgery. Uneventful recovery followed immediate repair. The difficulty of confirming rupture of a major airway is discussed and the importance of conserving the lung when the diagnosis has been missed is emphasised. Images PMID:3317977

  18. Blood flow characteristics in a terminal basilar tip aneurysm prior to its fatal rupture

    PubMed Central

    Sforza, D.M.; Putman, C.M.; Scrivano, E.; Lylyk, P.; Cebral, J.R.

    2010-01-01

    Background and Purpose The development and validation of methods to stratify the risk of rupture of cerebral aneurysms is highly desired since current treatment risks can exceed the natural risk of rupture. Because unruptured aneurysms are typically treated before they rupture, it is very difficult to connect the proposed risk indices to the rupture of an individual aneurysm. The purpose of this case study was to analyze the hemodynamic environment of a saccular aneurysm of the terminal morphology sub-type that was imaged just prior to its rupture and to test whether the hemodynamic characteristics would designate this particular aneurysm as at high risk. Methods A patient-specific computational fluid dynamics model was constructed from 3D rotational angiography images acquired just hours before the aneurysm ruptured. A pulsatile flow calculation was performed and hemodynamic characteristics previously connected to rupture were analyzed. Results It was found that the aneurysm had a concentrated inflow stream, small impingement region, complex intra-aneurysmal flow structure, asymmetric flow split from the parent vessel to the aneurysm and daughter branches, and high levels of aneurysmal wall shear stress near the impaction zone. Conclusions The hemodynamics characteristics observed in this aneurysm right before its rupture are consistent with previous studies correlating aneurysm rupture and hemodynamic patterns in saccular and terminal aneurysms. This study supports the notion that hemodynamic information may be used to help stratify the rupture risk of cerebral aneurysms. PMID:20150312

  19. Detection of vulnerable atherosclerosis plaques with a dual-modal single-photon-emission computed tomography/magnetic resonance imaging probe targeting apoptotic macrophages.

    PubMed

    Cheng, Dengfeng; Li, Xiao; Zhang, Chunfu; Tan, Hui; Wang, Cong; Pang, Lifang; Shi, Hongcheng

    2015-02-01

    Atherosclerosis (AS), especially the vulnerable AS plaque rupture-induced acute obstructive vascular disease, is a leading cause of death. Accordingly, there is a need for an effective method to draw accurate predictions about AS progression and plaque vulnerability. Herein we report on an approach to constructing a hybrid nanoparticle system using a single-photon-emission computed tomography (SPECT)/magnetic resonance imaging (MRI) multimodal probe, aiming for a comprehensive evaluation of AS progression by achieving high sensitivity along with high resolution. Ultrasmall superparamagnetic iron oxide (USPIO) was covered by aminated poly(ethylene glycol) (PEG) and carboxylated PEG simultaneously and then functionalized with diethylenetriaminepentacetate acid for (99m)Tc coordination and subsequently Annexin V for targeting apoptotic macrophages abundant in vulnerable plaques. The in vivo accumulations of imaging probe reflected by SPECT and MRI were consistent and accurate in highlighting lesions. Intense radioactive signals detected by SPECT facilitated focus recognization and quantification, while USPIO-based T2-weighted MRI improved the focal localization and volumetry of AS plaques. For subsequent ex vivo planar images, targeting effects were further confirmed by immunohistochemistry, including CD-68 and TUNEL staining; meanwhile, the degree of concentration was proven to be statistically correlated with the Oil Red O staining results. In conclusion, these results indicated that the Annexin V-modified hybrid nanoparticle system specifically targeted the vulnerable AS plaques containing apoptotic macrophages and could be of great value in the invasively accurate detection of vulnerable plaques. PMID:25569777

  20. Associations between Tobacco, Alcohol, and Drug Use with Coronary Artery Plaque among HIV-Infected and Uninfected Men in the Multicenter AIDS Cohort Study

    PubMed Central

    Kelly, Sean G.; Plankey, Michael; Post, Wendy S.; Li, Xiuhong; Stall, Ronald; Jacobson, Lisa P.; Witt, Mallory D.; Kingsley, Lawrence; Cox, Christopher; Budoff, Matthew; Palella, Frank J.

    2016-01-01

    Background We characterized associations between smoking, alcohol, and recreational drug use and coronary plaque by HIV serostatus within the Multicenter AIDS Cohort Study (MACS). Methods MACS participants (N = 1005, 621 HIV+ and 384 HIV-) underwent non-contrast CT scanning to measure coronary artery calcium; 764 underwent coronary CT angiograms to evaluate plaque type and extent. Self-reported use of alcohol, tobacco, smoked/inhaled cocaine, methamphetamine, ecstasy, marijuana, inhaled nitrites, and erectile dysfunction drugs was obtained at semi-annual visits beginning 10 years prior to CT scanning. Multivariable logistic and linear regression models were performed, stratified by HIV serostatus. Results Among HIV+ men, current smoking, former smoking, and cumulative pack years of smoking were positively associated with multiple coronary plaque measures (coronary artery calcium presence and extent, total plaque presence and extent, calcified plaque presence, and stenosis >50%). Smoking was significantly associated with fewer plaque measures of comparable effect size among HIV- men; current smoking and calcified plaque extent was the only such association. Heavy alcohol use (>14 drinks/week) was associated with stenosis >50% among HIV+ men. Among HIV- men, low/moderate (1–14 drinks/week) and heavy alcohol use were inversely associated with coronary artery calcium and calcified plaque extent. Few significant associations between other recreational drug use and plaque measures were observed. Conclusion Smoking is strongly associated with coronary plaque among HIV+ men, underscoring the value of smoking cessation for HIV+ persons. Alcohol use may protect against coronary artery calcium and calcified plaque progression in HIV- (but not HIV+) men. Few positive associations were observed between recreational drug use and coronary plaque measures. PMID:26811937

  1. Association between Randall's Plaque and Calcifying Nanoparticles

    NASA Technical Reports Server (NTRS)

    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.

    2007-01-01

    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.

  2. Adalimumab: A Review in Chronic Plaque Psoriasis.

    PubMed

    Burness, Celeste B; McKeage, Kate

    2015-12-01

    Adalimumab (Humira(®)) is a fully human monoclonal antibody against tumour necrosis factor (TNF), formulated for subcutaneous administration. It is well established in the treatment of adults with moderate-to-severe chronic plaque psoriasis and has recently received approval in the EU for the treatment of severe chronic plaque psoriasis in children and adolescents from 4 years of age. In a phase III trial in paediatric patients, a significantly greater proportion of patients receiving adalimumab 0.8 mg/kg (to a maximum of 40 mg) every other week (eow) achieved a ?75 % improvement from baseline in Psoriasis Area and Severity Index than those receiving methotrexate after 16 weeks of treatment. In adults, well-designed randomized clinical trials demonstrated that adalimumab 40 mg eow effectively reduced the signs and symptoms of psoriasis and improved dermatology-specific and general measures of health-related quality of life, with these benefits sustained during long-term treatment. Adalimumab was generally well tolerated, compared with placebo or methotrexate, during clinical trials in paediatric and adult patients with chronic plaque psoriasis. Thus, adalimumab remains an important treatment strategy in adults with moderate-to-severe chronic plaque psoriasis and provides a promising new systemic treatment option for children and adolescents from 4 years of age with severe psoriasis. PMID:26586242

  3. Magnetic resonance imaging of juxtapapillary plaques in cadaver eyes.

    PubMed Central

    Williams, D F; Mieler, W F; Jaffe, G J; Robertson, D M; Hendrix, L

    1990-01-01

    Adequate treatment of juxtapapillary melanomas with episcleral plaque brachytherapy using lower energy radiation sources may be difficult because of uncertainties regarding the relationship of the plaque to the optic nerve and tumour base. We obtained magnetic resonance images of a dummy plaque placed in a juxtapapillary location in cadaver specimens. Although it is possible to place a plaque in close association with the optic nerve sheath, a tissue barrier exists which may prevent actual contact between the plaque and nerve. Posterior tilting of the plaque may also occur. Because of these uncertainties regarding plaque placement, juxtapapillary melanomas should be considered a distinct subgroup when evaluating the efficacy of radioactive plaque brachytherapy in the treatment of choroidal melanoma. Images PMID:2306444

  4. Treating cardiovascular atherosclerotic plaques with Tongmaijiangzhi (TMJZ) capsule.

    PubMed

    Ren, Hong-Qiang; Zhao, Li; Zhang, Zhong Shuang; Wang, Zhong; Wang, Li; Duan, Jun Cang; Li, Li; Zhai, Zhi Hong; Qu, De Tao; Huang, Hui

    2013-01-01

    Atherosclerotic plaques can cause serious syndromes and mortality. Cholesterol accumulation in the plaques can disrupt the arterial flow, with lumen narrowing and stenosis, which contributes to heart attack and sudden cardiac death. The pharmacological treatment to atherosclerotic plaques can be anti-hypertensives, anti-cholesterol, and cleaning of the existed plaques. This work examined the effects of pharmacological Tongmaijiangzhi (TMJZ) capsule on atherosclerotic plaques. The radiological findings of the atherosclerotic plaques of 107 patients receiving TMJZ treatment were analyzed. We found that the TMJZ administration decreases plaque volume and alters the composition in a relatively short period, showing highly promising effects. TMJZ treatment is able to remove the existed atherosclerotic plaques with no side effects observed. PMID:24311866

  5. 18. Photocopy of drawing of bronze dedication plaque, circa 1903 ...

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

    18. Photocopy of drawing of bronze dedication plaque, circa 1903 (original drawing in possession of City Engineer's Office Grand Rapids, Michigan) DEDICATION PLAQUE. - Bridge Street Bridge, Spanning Grand River, Michigan & Bridge Streets, Grand Rapids, Kent County, MI

  6. DIFFERENTIAL EFFECT OF TETRAZOLIUM UPON BACTERIOPHAGE PLAQUE ASSAY TITERS

    EPA Science Inventory

    This study examined whether the practice of incorporating either tetrazolium red ortetrazolium violet dye into plaque assay medium deleteriously influences plaque assay titers. epresentative members of six different virus families were studied: ystoviridae (06), Leviviridae (MS2)...

  7. Regions of high wall stress can predict the future location of rupture of abdominal aortic aneurysm.

    PubMed

    Doyle, Barry J; McGloughlin, Timothy M; Miller, Karol; Powell, Janet T; Norman, Paul E

    2014-06-01

    Predicting the wall stress in abdominal aortic aneurysm (AAA) using computational modeling may be a useful adjunct to traditional clinical parameters that indicate the risk of rupture. Maximum diameter has been shown to have many limitations, and using current technology it is possible to provide a patient-specific computational risk assessment using routinely acquired medical images. We present a case of AAA rupture where the exact rupture point was clearly visible on the computed tomography (CT) images. A blind computational study based on CT scans acquired 4 months earlier predicted elevated wall stresses in the same region that later experienced rupture. PMID:24554200

  8. Spontaneous splenic rupture in pregnancy

    PubMed Central

    Elghanmi, Adil; Mohamed, Jou; Khabouz, Samira

    2015-01-01

    Splenic rupture during pregnancy is a rare and can frequently be a misdiagnosed pathology. This rupture is associated with a high maternal and fetal mortality rate. A 26 years old Moroccan woman para II gravida II presented at the third stage of pregnancy with acute onset of severe abdominal pain. She developed immediately a hypovolemic shock. After both a physical and sonographical exam, it was revealed that it was due to a massive hemoperitoneum. Therefore, an emergent laparotomy and cesarean delivery with abdominal exploration were performed; also, an active bleeding was identified at the splenic hilum consistent with splenic rupture. Through this case report, we want to raise awareness of this surgical emergency that requires immediate recognition because any delay can lead to catastrophic consequences PMID:26587160

  9. Non-popliteal synovial rupture.

    PubMed

    Sit, Michelle; Higgs, Jay B

    2009-06-01

    The ruptured popliteal synovial cyst is a common complication of chronic knee arthritis. In contrast, non-popliteal synovial rupture is less well recognized and may present a diagnostic dilemma. We report an 81-year-old woman who presented with chest wall pain and ecchymosis. Ultrasonography of the shoulder region readily diagnosed a dissecting parasynovial cyst. She developed the unusual complication of contralateral recurrence. Literature review revealed a small but important set of non-popliteal synovial ruptures in the regions of the shoulder, elbow, wrist, spine, hip, knee, and ankle. Local swelling, inflammation, ecchymosis, and nerve impingement may mimic other conditions. Awareness of the clinical presentations and a high index of suspicion are required to avoid diagnostic confusion. Management data are limited to case reports of arthrocentesis, injection, and very rarely, surgery. PMID:19390451

  10. Inflamed psoriatic plaques: Drug toxicity or disease exacerbation?

    PubMed Central

    Jindal, Nidhi; Arora, Kshama; Jindal, Pooja; Jain, Vijay Kumar; Ghosh, Sangita

    2013-01-01

    We are presenting a case of Methotrexate treated stable plaque psoriasis, in whom inflamed psoriatic plaques of drug toxicity were misdiagnosed as disease exacerbation. Erosive psoriatic plaques were present in the absence of biochemical or hematological derangements. Ulceration of psoriatic plaques in the presence of disturbed hematological profile is well described as a harbinger of methotrexate toxicity, but this kind of erosions in the absence of any systemic involvement is the first report of its kind. PMID:24014924

  11. Enzymatically triggered rupture of polymersomes.

    PubMed

    Jang, Woo-Sik; Park, Seung Chul; Reed, Ellen H; Dooley, Kevin P; Wheeler, Samuel F; Lee, Daeyeon; Hammer, Daniel A

    2016-01-20

    Polymersomes are robust vesicles made from amphiphilic block co-polymers. Large populations of uniform giant polymersomes with defined, entrapped species can be made by templating of double-emulsions using microfluidics. In the present study, a series of two enzymatic reactions, one inside and the other outside of the polymersome, were designed to induce rupture of polymersomes. We measured how the kinetics of rupture were affected by altering enzyme concentration. These results suggest that protocells with entrapped enzymes can be engineered to secrete contents on cue. PMID:26616557

  12. Polymeric nanoparticle PET/MR imaging allows macrophage detection in atherosclerotic plaques

    PubMed Central

    Majmudar, Maulik D.; Yoo, Jeongsoo; Keliher, Edmund J.; Truelove, Jessica; Iwamoto, Yoshiko; Sena, Brena; Dutta, Partha; Borodovsky, Anna; Fitzgerald, Kevin; Di Carli, Marcelo; Libby, Peter; Anderson, Daniel G.; Swirski, Filip K.; Weissleder, Ralph; Nahrendorf, Matthias

    2013-01-01

    Rationale Myeloid cell content in atherosclerotic plaques associates with rupture and thrombosis. Thus, imaging of lesional monocyte and macrophages (Mo/M?) could serve as a biomarker of disease progression and therapeutic intervention. Objective To noninvasively assess plaque inflammation with dextran nanoparticle-facilitated hybrid PET/MR imaging. Methods and Results Using clinically approved building blocks, we systematically developed 13nm polymeric nanoparticles consisting of crosslinked short chain dextrans which were modified with desferoxamine for zirconium-89 radiolabeling (89Zr-DNP) and a near infrared fluorochrome (VT680) for microscopic and cellular validation. Flow cytometry of cells isolated from excised aortas showed DNP uptake predominantly in Mo/M? (76.7%) and lower signal originating from other leukocytes such as neutrophils and lymphocytes (11.8% and 0.7%, p<0.05 versus Mo/M?). DNP colocalized with the myeloid cell marker CD11b on immunohistochemistry. PET/MRI revealed high uptake of 89Zr-DNP in the aortic root of ApoE?/? mice (standard uptake value, ApoE?/? mice versus wild type controls, 1.9±0.28 versus 1.3±0.03, p<0.05), corroborated by ex vivo scintillation counting and autoradiography. Therapeutic silencing of the monocyte-recruiting receptor CCR2 with siRNA decreased 89Zr-DNP plaque signal (p<0.05) and inflammatory gene expression (p<0.05). Conclusions Hybrid PET/MR imaging with a 13nm DNP enables noninvasive assessment of inflammation in experimental atherosclerotic plaques and reports on therapeutic efficacy of anti-inflammatory therapy. PMID:23300273

  13. Correlation of hemodynamic forces and atherosclerotic plaque components

    NASA Astrophysics Data System (ADS)

    Canton, Gádór; Chiu, Bernard; Yuan, Chun; Kerwin, William S.

    2010-02-01

    Local hemodynamic forces in atherosclerotic carotid arteries are thought to trigger cellular and molecular mechanisms that determine plaque vulnerability. 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 for 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. The aim of this study was to explore the hypothesis that intra-plaque hemorrhage, a feature associated with adverse outcomes and plaque progression, is more likely to occur in plaques with elevated WSS levels. We compared 2D representations of the WSS distribution and the amount of intra-plaque hemorrhage to determine relationships between WSS patterns and plaque vulnerability. We extracted WSS data to compare patterns between cases with and without hemorrhage. We found elevated values of WSS at regions where intra-plaque hemorrhage was detected, suggesting that WSS might be used as a marker for the risk of intra-plaque hemorrhage and subsequent complications.

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

    PubMed Central

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Tozian, Cynthia

    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.

  16. Film dosimetry analyses on the effect of gold shielding for Iodine-125 eye plaque therapy for choroidal melanoma

    SciTech Connect

    Wu, A. ); Krasin, F. )

    1990-09-01

    One of the methods currently being used to treat choroidal melanoma employs an episcleral plaque containing I-125 radioactive seeds. However, comprehensive dosimetry studies on the plaque are scarce and controversial. For this work, we use film to study the dosimetry outside the lip of the gold shield of the eye plaque. This lip around the gold shield was made to protect the critical structures behind and adjacent to the lesion. Since the changes of energy spectrum of I-125 in tissue are negligible, film dosimetry seems to be a logical choice because of high spatial resolution required around the lip of the gold plaque. For this study, we first established an H and D curve with dose expressed in a unit of specific dose rate constant. This avoids absolute dose measurements. All film density measurements are made with a 1-mm aperture scan, normalized to the density at the prescription point for tumor of 3--5-mm apical height, i.e., 5 mm from the interior surface of sclera, and converted to percentage isodose curves. With a gold shield, it is found that when the plaque is placed against the optical nerve, the optical disk and macula, located at 2 mm outside the lip, on the exterior surface of sclera, may receive 85% of the prescription dose for a 12-mm plaque and 58% for a 16-mm plaque. For tumors of 8-mm apical height, the optical nerve would receive more than the prescription dose.

  17. Film dosimetry analyses on the effect of gold shielding for iodine-125 eye plaque therapy for choroidal melanoma.

    PubMed

    Wu, A; Krasin, F

    1990-01-01

    One of the methods currently being used to treat choroidal melanoma employs an episcleral plaque containing I-125 radioactive seeds. However, comprehensive dosimetry studies on the plaque are scarce and controversial. For this work, we use film to study the dosimetry outside the lip of the gold shield of the eye plaque. This lip around the gold shield was made to protect the critical structures behind and adjacent to the lesion. Since the changes of energy spectrum of I-125 in tissue are negligible, film dosimetry seems to be a logical choice because of high spatial resolution required around the lip of the gold plaque. For this study, we first established an H and D curve with dose expressed in a unit of specific dose rate constant. This avoids absolute dose measurements. All film density measurements are made with a 1-mm aperture scan, normalized to the density at the prescription point for tumor of 3-5-mm apical height, i.e., 5 mm from the interior surface of sclera, and converted to percentage isodose curves. With a gold shield, it is found that when the plaque is placed against the optical nerve, the optical disk and macula, located at 2 mm outside the lip, on the exterior surface of sclera, may receive 85% of the prescription dose for a 12-mm plaque and 58% for a 16-mm plaque. For tumors of 8-mm apical height, the optical nerve would receive more than the prescription dose. PMID:2233570

  18. Vortex dynamics in ruptured and unruptured intracranial aneurysms

    NASA Astrophysics Data System (ADS)

    Trylesinski, Gabriel

    Intracranial aneurysms (IAs) are a potentially devastating pathological dilation of brain arteries that affect 1.5-5 % of the population. Causing around 500 000 deaths per year worldwide, their detection and treatment to prevent rupture is critical. Multiple recent studies have tried to find a hemodynamics predictor of aneurysm rupture, but concluded with distinct opposite trends using Wall Shear Stress (WSS) based parameters in different clinical datasets. Nevertheless, several research groups tend to converge for now on the fact that the flow patterns and flow dynamics of the ruptured aneurysms are complex and unstable. Following this idea, we investigated the vortex properties of both unruptured and ruptured cerebral aneurysms. A brief comparison of two Eulerian vortex visualization methods (Q-criterion and lambda 2 method) showed that these approaches gave similar results in our complex aneurysm geometries. We were then able to apply either one of them to a large dataset of 74 patient specific cases of intracranial aneurysms. Those real cases were obtained by 3D angiography, numerical reconstruction of the geometry, and then pulsatile CFD simulation before post-processing with the mentioned vortex visualization tools. First we tested the two Eulerian methods on a few cases to verify their implementation we made as well as compare them with each other. After that, the Q-criterion was selected as method of choice for its more obvious physical meaning (it shows the balance between two characteristics of the flow, its swirling and deformation). Using iso-surfaces of Q, we started by categorizing the patient-specific aneurysms based on the gross topology of the aneurysmal vortices. This approach being unfruitful, we found a new vortex-based characteristic property of ruptured aneurysms to stratify the rupture risk of IAs that we called the Wall-Kissing Vortices, or WKV. We observed that most ruptured aneurysms had a large amount of WKV, which appears to agree with the current hypothesized biological triggers of pathological remodeling of the artery walls. Having a good natural ratio of statuses in our IA cohort (55 unruptured vs. 19 ruptured), we were able to test the statistical significance of our predictor to fortify our findings. We also performed a distribution analysis of our cohort with respect to the number of WKV to strengthen the encouraging statistical analysis result; both analyses provided a clear good separation of the status of the aneurysms based on our predictor. Lastly, we constructed a receiver operating characteristic (ROC) curve to analyze the power different thresholds of WKV had in splitting the data in a binary way (unruptured/ruptured). The number of WKV was efficaciously able to stratify the rupture status, identifying 84.21 % of the ruptured aneurysms (with 25.45 % of false positives, i.e. unruptured IAs tagged as ruptured) when using a threshold value of 2. Our novel work undertaken to study the vortex structures in IAs brought to light interesting characteristics of the flow in the aneurysmal sac. We found that there are several distinct categories in which the aneurysm vortex topologies can be put in without relationship to the aneurysm rupture status. This first finding was in contradiction with available already-published results. Nonetheless, ruptured IAs had a statistically significant larger amount of WKV as opposed to unruptured aneurysms. This new predictor we propose to the community could very well clear a new path among the currently controversial WSS-based parameters. Although it needs to be improved to be more resilient, the first results obtained by the WKV-based parameter are promising when applied to a large dataset of 74 IAs patient-specific transient CFD simulations.

  19. Icaritin Inhibits Collagen Degradation-Related Factors and Facilitates Collagen Accumulation in Atherosclerotic Lesions: A Potential Action for Plaque Stabilization.

    PubMed

    Zhang, Zong-Kang; Li, Jie; Yan, De-Xin; Leung, Wing-Nang; Zhang, Bao-Ting

    2016-01-01

    Most acute coronary syndromes result from rupture of vulnerable atherosclerotic plaques. The collagen content of plaques may critically affect plaque stability. This study tested whether Icaritin (ICT), an intestinal metabolite of Epimedium-derived flavonoids, could alter the collagen synthesis/degradation balance in atherosclerotic lesions. Rabbits were fed with an atherogenic diet for four months. Oral administration of ICT (10 mg·kg(-1)·day(-1)) was started after two months of an atherogenic diet and lasted for two months. The collagen degradation-related parameters, including macrophages accumulation, content and activity of interstitial collagenase-1 (MMP-1), and the collagen synthesis-related parameters, including amount and distribution of smooth muscle cells (SMC) and collagen mRNA/protein levels, were evaluated in the aorta. ICT reduced plasma lipid levels, inhibited macrophage accumulation, lowered MMP-1 mRNA and protein expression, and suppressed proteolytic activity of pro-MMP-1 and MMP-1 in the aorta. ICT changed the distribution of the SMCs towards the fibrous cap of lesions without increasing the amount of SMCs. Higher collagen protein content in lesions and aorta homogenates was observed with ICT treatment compared with the atherogenic diet only, without altered collagen mRNA level. These results suggest that ICT could inhibit the collagen degradation-related factors and facilitate collagen accumulation in atherosclerotic lesions, indicating a new potential of ICT in atherosclerotic plaques. PMID:26828485

  20. Icaritin Inhibits Collagen Degradation-Related Factors and Facilitates Collagen Accumulation in Atherosclerotic Lesions: A Potential Action for Plaque Stabilization

    PubMed Central

    Zhang, Zong-Kang; Li, Jie; Yan, De-Xin; Leung, Wing-Nang; Zhang, Bao-Ting

    2016-01-01

    Most acute coronary syndromes result from rupture of vulnerable atherosclerotic plaques. The collagen content of plaques may critically affect plaque stability. This study tested whether Icaritin (ICT), an intestinal metabolite of Epimedium-derived flavonoids, could alter the collagen synthesis/degradation balance in atherosclerotic lesions. Rabbits were fed with an atherogenic diet for four months. Oral administration of ICT (10 mg·kg−1·day−1) was started after two months of an atherogenic diet and lasted for two months. The collagen degradation-related parameters, including macrophages accumulation, content and activity of interstitial collagenase-1 (MMP-1), and the collagen synthesis-related parameters, including amount and distribution of smooth muscle cells (SMC) and collagen mRNA/protein levels, were evaluated in the aorta. ICT reduced plasma lipid levels, inhibited macrophage accumulation, lowered MMP-1 mRNA and protein expression, and suppressed proteolytic activity of pro-MMP-1 and MMP-1 in the aorta. ICT changed the distribution of the SMCs towards the fibrous cap of lesions without increasing the amount of SMCs. Higher collagen protein content in lesions and aorta homogenates was observed with ICT treatment compared with the atherogenic diet only, without altered collagen mRNA level. These results suggest that ICT could inhibit the collagen degradation-related factors and facilitate collagen accumulation in atherosclerotic lesions, indicating a new potential of ICT in atherosclerotic plaques. PMID:26828485

  1. The explosive growth of small voids in vulnerable cap rupture; cavitation and interfacial debonding

    PubMed Central

    Maldonado, Natalia; Kelly-Arnold, Adreanne; Cardoso, Luis; Weinbaum, Sheldon

    2013-01-01

    While it is generally accepted that ruptures in fibrous cap atheromas cause most acute coronary deaths, and that plaque rupture occurs in the fibrous cap at the location where the tissue stress exceeds a certain critical peak circumferential stress, the exact mechanism of rupture initiation remains unclear. We recently reported the presence of multiple microcalcifications (μCalcs) < 50μm diameter embedded within the fibrous cap, μCalcs that could greatly increase cap instability by introducing up to a 5-fold increase in local tissue stress. Here, we explore the hypothesis that, aside from cap thickness, μCalc size and interparticle spacing are principal determinants of cap rupture risk. Also, we propose that cap rupture is initiated near the poles of the μCalcs due to the presence of tiny voids that explosively grow at a critical tissue stress and then propagate across the fibrous cap. We develop a theoretical model based on classic studies in polymeric materials by Gent (1980), which indicates that cavitation as opposed to interfacial debonding is the more likely mechanism for cap rupture produced by μCalcs < 65μm diameter. This analysis suggests that there is a critical μCalc size range, from 5μm to 65μm, in which cavitation should be prevalent. This hypothesis for cap rupture is strongly supported by our latest μCT studies in which we have observed trapped voids in the vicinity of μCalcs within fibrous caps in human coronaries. PMID:23218838

  2. Predictive biomechanical analysis of ascending aortic aneurysm rupture potential

    PubMed Central

    Martin, Caitlin; Sun, Wei; Pham, Thuy; Elefteriades, John

    2013-01-01

    Aortic aneurysm is a leading cause of death in adults, often taking lives without any premonitory signs or symptoms. Adverse clinical outcomes of aortic aneurysm are preventable by elective surgical repair; however, identifying at-risk individuals is difficult. The objective of this study was to perform a predictive biomechanical analysis of ascending aortic aneurysm (AsAA) tissue to assess rupture risk on a patient-specific level. AsAA tissues, obtained intra-operatively from 50 patients, were subjected to biaxial mechanical and uniaxial failure tests to obtain their passive elastic mechanical properties. A novel analytical method was developed to predict the AsAA pressure-diameter response as well as the aortic wall yield and failure responses. Our results indicated that the mean predicted AsAA diameter at rupture was 5.6 ± 0.7 cm, and the associated blood pressure to induce rupture was 579.4 ± 214.8 mmHg. Statistical analysis showed significant positive correlation between aneurysm tissue compliance and predicted risk of rupture, where patients with a pressure-strain modulus ≥100 kPa may be nearly twice as likely to experience rupture than patients with more compliant aortic tissue. The mechanical analysis of pre-dissection patient tissue properties established in this study could predict the “future” onset of yielding and rupture in AsAA patients. The analysis results implicate decreased tissue compliance as a risk factor for AsAA rupture. The presented methods may serve as a basis for the development of a pre-operative planning tool for AsAA evaluation, a tool currently unavailable. PMID:23948500

  3. Rupture of spleen post colonoscopy.

    PubMed

    Younes, Nidal A; Al-Ardah, Mahmoud I; Daradkeh, Salam S

    2009-08-01

    We review an interesting case of elective colonoscopy for rectal bleeding in a 68-year-old woman complicated by splenic rupture. She was managed by aggressive fluid and blood resuscitation followed by splenectomy. She had a smooth recovery and was discharged home 4 days after admission. The extreme rarity and interesting clinical course of the patient are discussed. PMID:19668895

  4. Effects of nine weeks' use of a new stabilized stannous fluoride dentifrice on intrinsic plaque virulence expressed as acidogenicity and regrowth: a modified PGRM study.

    PubMed

    Kasturi, R; White, D J; Lanzalaco, A C; Macksood, D; Cox, E R; Bacca, L; Liang, N; Baker, R

    1995-01-01

    A new stabilized stannous fluoride dentifrice, currently marketed as Crest Gum Care has been examined for its effects on intrinsic plaque metabolic and regrowth activity and effects on plaque resistance to SnF2 throughout nine weeks of toothbrushing. Subjects brushed their teeth 1 X, 2 X or 3 X/day with stabilized stannous fluoride dentifrice or placebo dentifrice for nine weeks, presenting in the morning on weeks 3, 6-9 for plaque sampling. Following nine weeks, subjects were crossed-over and repeated the experiment on their alternative assigned product (active SnF2/placebo). Sampled dental plaques were evaluated for standardized glycolysis and regrowth activity using the "Plaque Glycolysis and Regrowth Method" (PGRM). Following the second nine-week treatment period, subjects concluding either placebo or SnF2 toothbrushing participated in a single-treatment PGRM experiment using stabilized stannous fluoride dentifrice. Toothbrushing with stabilized stannous fluoride dentifrice in this experiment produced significant and sustained reductions in both plaque glycolytic and regrowth activity as compared to placebo treated plaques. In the concluding single-brushing PGRM experiment, SnF2 dentifrice was shown to produce equal inhibitory actions in plaque from subjects completing stannous fluoride or placebo treatments. This result confirmed that nine weeks toothbrushing with stabilized stannous fluoride dentifrice produced no development or resistance of plaque to SnF2 inhibition. These results support the strong in vivo antimicrobial actions of the stabilized stannous fluoride dentifrice, Crest Gum Care. PMID:8593196

  5. (99m)Tc-labelled anti-CD11b SPECT/CT imaging allows detection of plaque destabilization tightly linked to inflammation.

    PubMed

    Liu, Guobing; Hu, Yan; Xiao, Jie; Li, Xiao; Li, Yanli; Tan, Hui; Zhao, Yanzhao; Cheng, Dengfeng; Shi, Hongcheng

    2016-01-01

    It remains challenging to predict the risk of rupture for a specific atherosclerotic plaque timely, a thrombotic trigger tightly linked to inflammation. CD11b, is a biomarker abundant on inflammatory cells, not restricted to monocytes/macrophages. In this study, we fabricated a probe named as (99m)Tc-MAG3-anti-CD11b for detecting inflamed atherosclerotic plaques with single photon emission computed tomography/computed tomography (SPECT/CT). The ApoE-knockout (ApoE(-/-)) mice were selected to establish animal models, with C57BL/6J mice used for control. A higher CD11b(+)-cell recruitment with higher CD11b expression and more serious whole-body inflammatory status were identified in ApoE(-/-) mice. The probe showed high in vitro affinity and specificity to the Raw-264.7 macrophages, as well as inflammatory cells infiltrated in atherosclerotic plaques, either in ex vivo fluorescent imaging or in in vivo micro-SPECT/CT imaging, which were confirmed by ex vivo planar gamma imaging, Oil-Red-O staining and CD11b-immunohistochemistry staining. A significant positive relationship was identified between the radioactivity intensity on SPECT/CT images and the CD11b expression in plaques. In summary, this study demonstrates the feasibility of anti-CD11b antibody mediated noninvasive SPECT/CT imaging of inflammatory leukocytes in murine atherosclerotic plaques. This imaging strategy can identify inflammation-rich plaques at risk for rupture and evaluate the effectiveness of inflammation-targeted therapies in atheroma. PMID:26877097

  6. 99mTc-labelled anti-CD11b SPECT/CT imaging allows detection of plaque destabilization tightly linked to inflammation

    PubMed Central

    Liu, Guobing; Hu, Yan; Xiao, Jie; Li, Xiao; Li, Yanli; Tan, Hui; Zhao, Yanzhao; Cheng, Dengfeng; Shi, Hongcheng

    2016-01-01

    It remains challenging to predict the risk of rupture for a specific atherosclerotic plaque timely, a thrombotic trigger tightly linked to inflammation. CD11b, is a biomarker abundant on inflammatory cells, not restricted to monocytes/macrophages. In this study, we fabricated a probe named as 99mTc-MAG3-anti-CD11b for detecting inflamed atherosclerotic plaques with single photon emission computed tomography/computed tomography (SPECT/CT). The ApoE-knockout (ApoE−/−) mice were selected to establish animal models, with C57BL/6J mice used for control. A higher CD11b+-cell recruitment with higher CD11b expression and more serious whole-body inflammatory status were identified in ApoE−/− mice. The probe showed high in vitro affinity and specificity to the Raw-264.7 macrophages, as well as inflammatory cells infiltrated in atherosclerotic plaques, either in ex vivo fluorescent imaging or in in vivo micro-SPECT/CT imaging, which were confirmed by ex vivo planar gamma imaging, Oil-Red-O staining and CD11b-immunohistochemistry staining. A significant positive relationship was identified between the radioactivity intensity on SPECT/CT images and the CD11b expression in plaques. In summary, this study demonstrates the feasibility of anti-CD11b antibody mediated noninvasive SPECT/CT imaging of inflammatory leukocytes in murine atherosclerotic plaques. This imaging strategy can identify inflammation-rich plaques at risk for rupture and evaluate the effectiveness of inflammation-targeted therapies in atheroma. PMID:26877097

  7. [Erionite-induced pleural plaques. Exposition to urban pollution in a female Turkish migrant in Germany].

    PubMed

    Gräsel, B; Kaya, A; Stahl, U; Rauber, K; Kuntz, C

    2008-06-01

    Erionite is a zeolite mineral of volcanic origin which contains no asbestos. It is found in different regions of the world, including southeast Turkey in ash and dust, from which it can cause inflammatory pleural plaques or malignant pleural mesothelioma (MPM). We report a female Turkish migrant exposed to urban pollution in her home country who decades later suffered from pleural plaques with a nonspecific chronic inflammatory disease. The differential diagnosis of inflammatory pleural plaques was assumed radiologically and confirmed by video-assisted thoracoscopic biopsy. Short-term clinical and radiologic control of the patient will be necessary because of the risk of MPM. For epidemiologic considerations discussed referring to current literature, a growing incidence of this type of disease in migrants from high-risk areas must be reckoned with in Germany, even without exposition to asbestos. PMID:18506411

  8. Beyond Coronary Stenosis: Coronary Computed Tomographic Angiography for the Assessment of Atherosclerotic Plaque Burden

    PubMed Central

    Kwan, Alan C; Cater, George; Vargas, Jose

    2013-01-01

    Coronary computed tomographic angiography (CCTA) is emerging as a key non-invasive method for assessing cardiovascular risk by measurement of coronary stenosis and coronary artery calcium (CAC). New advancements in CCTA technology have led to the ability to directly identify and quantify the so-called “vulnerable” plaques that have features of positive remodeling and low density components. In addition, CCTA presents a new opportunity for noninvasive measurement of total coronary plaque burden that has not previously been available. The use of CCTA needs also to be balanced by its risks and, in particular, the associated radiation exposure. We review current uses of CCTA, CCTA’s ability to measure plaque quantity and characteristics, and new developments in risk stratification and CCTA technology. CCTA represents a quickly developing field that will play a growing role in the non-invasive management of cardiovascular disease. PMID:23524381

  9. Atherosclerotic plaque characterization by spatial and temporal speckle pattern analysis

    NASA Astrophysics Data System (ADS)

    Tearney, Guillermo J.; Bouma, Brett E.

    2002-04-01

    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.

  10. Computed tomography imaging of coronary artery plaque: characterization and prognosis.

    PubMed

    Baumann, Stefan; Renker, Matthias; Meinel, Felix G; Wichmann, Julian L; Fuller, Stephen R; Bayer, Richard R; Schoepf, U Joseph; Steinberg, Daniel H

    2015-03-01

    The exact definition and prognostication of vulnerable plaque remain elusive, and multiple imaging modalities aim to identify these plaques. As a noninvasive technique for the diagnosis of coronary artery disease, coronary computed tomography angiography has become increasingly utilized, primarily in patients with an elevated cardiovascular risk profile. Recent advances in technical methods have allowed for improved visualization of the vessel wall and surrounding tissue, allowing for improved characterization of vulnerable plaques by identifying features such as low-density plaques, positive remodeling, and spotty calcification. Quantification and qualification of these plaques may enhance the ability to predict future cardiovascular events. PMID:25726996

  11. Lymphocyte Migration into Atherosclerotic Plaque

    PubMed Central

    Li, Jie; Ley, Klaus

    2015-01-01

    Adaptive immunity is involved in the pathogenesis of atherosclerosis, but the recruitment of T and B lymphocytes to atherosclerotic lesions is not as well studied as that of monocytes. In this review, we summarize the current understanding of the role of lymphocyte subsets in the pathogenesis of atherosclerosis and discuss chemokines and chemokine receptors involved in lymphocyte homing to atherosclerotic lesions. We review evidence for involvement of the chemokines CCL5, CCL19, CCL21, CXCL10, CXCL16 and macrophage migration inhibitory factor in lymphocyte homing in atherosclerosis. Also, we review the role of their receptors CCR5, CCR6, CCR7, CXCR3, CXCR6, CXCR2/CXCR4 and the role of the L-selectin in mouse models of atherosclerosis. PMID:25301842

  12. Quadriceps Tendon Rupture due to Postepileptic Convulsion

    PubMed Central

    Erkut, Adem; Guvercin, Yilmaz; Sahin, Rifat; Keskin, Davut

    2014-01-01

    We present a case of quadriceps tendon (QT) rupture. QT ruptures can occur in all ages. The cause is mostly traumatic in origin. Spontaneous ruptures that are thought to result from predisposing conditions are rare. Post-convulsion QT ruptures lacking traumas in their history can be overlooked in clinical examinations. This should be born in mind by the attending physician, as early diagnosis and treatment of the condition can lead to satisfactory outcomes. PMID:24944977

  13. Analyzing Single-Event Gate Ruptures In Power MOSFET's

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.

    1993-01-01

    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.

  14. Comparison of Gadofluorine-M and Gd-DTPA for Non-Invasive Staging of Atherosclerotic Plaque Stability Using MRI

    PubMed Central

    Ronald, John A.; Chen, Yuanxin; Belisle, Andre J.-L.; Hamilton, Amanda M.; Rogers, Kem A.; Hegele, Robert A.; Misselwitz, Bernd; Rutt, Brian K.

    2009-01-01

    Background Inflammation and neovascularization play critical roles in the stability of atherosclerotic plaques. Whole-body quantitative assessment of these plaque features may improve patient risk-stratification for life-threatening thromboembolic events and direct appropriate intervention. Here we determined the utility of the MR contrast agent Gadofluorine-M (GdF) for staging plaque stability and compared this to the conventional agent Gd-DTPA. Methods and Results 5 control and 7 atherosclerotic rabbits were sequentially imaged following administration of Gd-DTPA (0.2 mmol/kg) and GdF (0.1 mmol/kg) using a T1-weighted pulse sequence on a 3T MRI scanner. Diseased aortic wall could be distinguished from normal wall based on wall-to-muscle contrast-to-noise values following GdF administration. RAM-11 (macrophages) and CD-31 (endothelial cells) immunostaining of MR-matched histological sections revealed that GdF accumulation was related to the degree of inflammation at the surface of plaques and the extent of core neovascularization. Importantly, an MR measure of GdF accumulation at both 1 and 24 hours post-injection, but not Gd-DTPA at peak enhancement, was shown to correlate with a quantitative histological morphology index related to these two plaque features. Conclusions GdF-enhanced MRI of atherosclerotic plaques allows non-invasive quantitative information about plaque composition to be acquired at multiple time points post-injection (within 1 and up to 24 hours post-injection). This dramatically widens the imaging window for assessing plaque stability that is currently attainable with clinically approved MR agents, therefore opening the possibility of whole-body (including coronary) detection of unstable plaques in the future and potentially improved mitigation of cataclysmic cardiovascular events. PMID:19808597

  15. Histopathological findings in spontaneous tendon ruptures.

    PubMed

    Józsa, L; Kannus, P

    1997-04-01

    A spontaneous rupture of a tendon may be defined as a rupture that occurs during movement and activity, that should not and usually does not damage the involved musculotendinous units (1). Spontaneous tendon ruptures were uncommon before the 1950s. Böhler found only 25 Achilles tendon ruptures in Wien between 1925 and 1948 (2). Mösender & Klatnek treated 20 Achilles tendon ruptures between 1953 and 1956, but 105 ruptures between 1964 and 1967 (3). Lawrence et al. found only 31 Achilles tendon ruptures in Boston during a period of 55 years (1900-1954) (4). During the recent decades tendon ruptures have, however, become relatively common in developed countries, especially in Europe and North America. A high incidence of tendon ruptures has been reported in Austria, Denmark, Finland, Germany. Hungary, Sweden, Switzerland and the USA; somewhat lower incidences have been reported in Canada, France, Great Britain and Spain. On the other hand, Greece, Japan, the Netherlands and Portugal have reported a clearly lower incidence. Interestingly, Achilles tendon ruptures are a rarity in developing countries, especially in Africa and East-Asia (5). In many developed countries, the increases in the rupture incidence have been dramatic. In the National Institute of Traumatology in Budapest, Hungary, the number of patients with an Achilles tendon rupture increased 285% in men and 500% in women between two successive 7-year periods, 1972-1978 and 1979-1985 (5). PMID:9211612

  16. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  17. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  18. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  19. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  20. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Rupture disc. 64.61 Section 64.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture...

  1. Plaque Production by Arboviruses in Singh's Aedes albopictus Cells

    PubMed Central

    Yunker, C. E.; Cory, J.

    1975-01-01

    We report plaquing tests of 124 virus strains, mostly arboviruses of 21 serological groups, in Singh's line of Aedes albopictus cells. Thirty of these plaqued; all were arboviruses of six groups and were known or presumed to be mosquito borne. Failing to plaque were 86 strains of arboviruses, mostly tick borne, two strains of insect pathogens, and six animal viruses not classified as arboviruses. Among mosquito-borne agents, plaquing ability appeared related to serological classification. California group and most A-group viruses failed to plaque, but nearly all members of B and Bunyamwera groups readily plaqued. Within serological group B, 14 of 16 mosquito-borne agents plaqued, but none of 13 tick-borne or vector-unassociated viruses did so. Some implications of these results for recognition and classification of arboviruses are discussed. Images PMID:234160

  2. Enucleation versus plaque irradiation for choroidal melanoma

    SciTech Connect

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

    1988-07-01

    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.

  3. Choroidal melanoma: I-125 plaque therapy

    SciTech Connect

    Bosworth, J.L.; Packer, S.; Rotman, M.; Ho, T.; Finger, P.T.

    1988-10-01

    An iodine-125 eye plaque was used to treat 58 patients with choroidal melanoma. Patients were followed up for a mean of 48.7 months. Fifty patients had medium-sized lesions (height between 3.1 and 8.0 mm and base diameter less than 16.0 mm), and six patients had large lesions. There were 24 lesions less than 3.0 mm from the optic nerve. The average radiation dose to the apex of the tumor was 8,468 cGy (dose rate, 71 cGy per hour). Initial local disease control was achieved in 50 patients (86.2%). One patient with local treatment failure received another plaque treatment, which controlled disease, so the total disease control rate was 87.9%. Only eight patients died of their disease. Complications were similar to those with other treatment methods, but none of the patients in this study developed optic nerve atrophy.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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.

  5. Macrophage iron, hepcidin, and atherosclerotic plaque stability.

    PubMed

    Sullivan, Jerome L

    2007-09-01

    Hepcidin has emerged as the key hormone in the regulation of iron balance and recycling. Elevated levels increase iron in macrophages and inhibit gastrointestinal iron uptake. The physiology of hepcidin suggests an additional mechanism by which iron depletion could protect against atherosclerotic lesion progression. Without hepcidin, macrophages retain less iron. Very low hepcidin levels occur in iron deficiency anemia and also in homozygous hemochromatosis. There is defective retention of iron in macrophages in hemochromatosis and also evidently no increase in atherosclerosis in this disorder. In normal subjects with intact hepcidin responses, atherosclerotic plaque has been reported to have roughly an order of magnitude higher iron concentration than that in healthy arterial wall. Hepcidin may promote plaque destabilization by preventing iron mobilization from macrophages within atherosclerotic lesions; the absence of this mobilization may result in increased cellular iron loads, lipid peroxidation, and progression to foam cells. Marked downregulation of hepcidin (e.g., by induction of iron deficiency anemia) could accelerate iron loss from intralesional macrophages. It is proposed that the minimally proatherogenic level of hepcidin is near the low levels associated with iron deficiency anemia or homozygous hemochromatosis. Induced iron deficiency anemia intensely mobilizes macrophage iron throughout the body to support erythropoiesis. Macrophage iron in the interior of atherosclerotic plaques is not exempt from this process. Decreases in both intralesional iron and lesion size by systemic iron reduction have been shown in animal studies. It remains to be confirmed in humans that a period of systemic iron depletion can decrease lesion size and increase lesion stability as demonstrated in animal studies. The proposed effects of hepcidin and iron in plaque progression offer an explanation of the paradox of no increase in atherosclerosis in patients with hemochromatosis despite a key role of iron in atherogenesis in normal subjects. PMID:17720947

  6. Retroperitoneal liposarcoma associated with small plaque parapsoriasis

    PubMed Central

    Tartaglia, Francesco; Blasi, Sara; Sgueglia, Monica; Polichetti, Paolo; Tromba, Luciana; Berni, Alberto

    2007-01-01

    Background Extremely rare cases of paraneoplastic syndromes or ectopic production of proteins associated with liposarcoma are reported in literature. Production of Granulocyte-Colony Stimulating Factor, alpha-fetoprotein, paraneoplastic pemphigus and leucocytosis, Acrokeratosis paraneoplastica (Bazex's syndrome) are reported. The present report describes a case of retroperitoneal liposarcoma associated with small plaque parapsoriasis. Our search in the English literature of such a kind of association did not reveal any case reported. Case presentation A 74 year male patient was admitted to our hospital because of the presence of an abdominal mass in right iliac fossa. He also complained of a two-year history of psoriasiform eruptions. The CT scan showed a retroperitoneal pelvic mass. Therefore surgical resection of the tumor was performed. After surgery, the skin eruptions disappeared completely in seven days and so a diagnosis of parapsoriasis syndrome was done. Conclusion Parallel disappearing of skin eruptions after surgery, typical clinical picture and not specific histology of the cutaneous lesions suggest the diagnosis of small plaque parapsoriasis. Therefore we propose to add Small Plaque Parapsoriasis to the list of paraneoplastic syndromes associated to liposarcoma. PMID:17620118

  7. Angiogenesis in human coronary atherosclerotic plaques.

    PubMed Central

    O'Brien, E. R.; Garvin, M. R.; Dev, R.; Stewart, D. K.; Hinohara, T.; Simpson, J. B.; Schwartz, S. M.

    1994-01-01

    Neovascularization in the walls of coronary arteries is associated with the presence of atherosclerotic plaque. The mechanisms responsible for the formation of these intraplaque microvessels are not understood. The purpose of this study is to examine the prevalence of endothelial cell replication in plaque microvessels. Two hundred and one primary and restenotic coronary atherectomy specimens were analyzed for the presence of microvessels and proliferation as reflected by positive immunolabeling for Ulex agglutinin and the proliferating cell nuclear antigen, respectively. In primary but not restenotic specimens, proliferation of any cell type was associated with the detection of microvessels on the same slide. However, intraplaque microvessels were more commonly found in restenotic compared to primary specimens (P = 0.004). Twelve highly vascularized specimens with evidence of replication were subjected to detailed histomorphological and quantitative image analyses. At 200 x, the most vascular optical field of each slide was identified and consistently included plaque macrophages. Total slide endothelial cell replication indices for these specimens varied, but in some instances were remarkably elevated (eg, 43.5%). The role of intraplaque angiogenesis may be analogous to that of tumor or wound angiogenesis and be important in development and progression of coronary artery lesions and restenosis. Images Figure 4 Figure 5 PMID:7524331

  8. Cataractogenesis after Cobalt-60 eye plaque radiotherapy

    SciTech Connect

    Kleineidam, M.; Augsburger, J.J. ); Hernandez, C.; Glennon, P.; Brady, L.W. )

    1993-07-15

    This study was designed to estimate the actuarial incidence of typical postirradiation cataracts and to identify prognostic factors related to their development in melanoma-containing eyes treated by Cobalt-60 plaque radiotherapy. A special interest was the impact of calculated radiation dose and dose-rate to the lens. The authors evaluated the actuarial occurrence of post-irradiation cataract in 365 patients with primary posterior uveal melanoma treated by Cobalt-60 plaque radiotherapy between 1976 and 1986. Only 22% (S.E. = 4.6%) of the patients who received a total dose of 6 to 20 Gy at the center of the lens developed a visually significant cataract attributable to the radiation within 5 years after treatment. Using multivariate Cox proportional hazards modeling, the authors identified thickness of the tumor, location of the tumor's anterior margin relative to the equatorward and the ora serrata, and diameter of the eye plaque used as the best combination of covariables for predicting length of time until development of cataract. Surprisingly, the dose of radiation delivered to the lens, which was strongly correlated to all of these covariables, was not a significant predictive factor in multivariate analysis. The results suggest that success of efforts to decrease the occurrence rate of post-irradiation cataracts by better treatment planning might be limited in patients with posterior uveal melanoma. 21 refs., 2 figs., 5 tabs.

  9. Curcumin Targeted, Polymalic Acid-Based MRI Contrast Agent for the Detection of Aβ Plaques in Alzheimer's Disease.

    PubMed

    Patil, Rameshwar; Gangalum, Pallavi R; Wagner, Shawn; Portilla-Arias, Jose; Ding, Hui; Rekechenetskiy, Arthur; Konda, Bindu; Inoue, Satoshi; Black, Keith L; Ljubimova, Julia Y; Holler, Eggehard

    2015-09-01

    Currently, there is no gadolinium-based contrast agent available for conventional magnetic resonance imaging (MRI) detection of amyloidal beta (Aβ) plaques in Alzheimer's disease (AD). Its timely finding would be vital for patient survival and quality of life. Curcumin (CUR), a common Indian spice effectively binds to Aβ plaques which is a hallmark of AD. To address this binding, we have designed a novel nanoimaging agent (NIA) based on nature-derived poly(β-l-malic acid) (PMLA) containing covalently attached gadolinium-DOTA(Gd-DOTA) and nature-derived CUR. The all-in-one agent recognizes and selectively binds to Aβ plaques and is detected by MRI. It efficiently detected Aβ plaques in human and mouse samples by an ex vivo staining. The method can be useful in clinic for safe and noninvasive diagnosis of AD. PMID:26036700

  10. Factors influencing maternal survival in ruptured uterus.

    PubMed

    Megafu, U

    1985-12-01

    Ruptured uterus continues to be a common obstetric hazard in under developed countries. The commonest cause is spontaneous rupture from obstructed labor in the multipara. There was not a single rupture in the primipara. Rupture following previous cesarean section scar is also common. The most effective way of management is to correct fluid and blood loss followed by laparotomy and subtotal hysterectomy. This method gave a lower mortality than either repair and sterilization or total hysterectomy. Adequate pre-operative resuscitation and time interval between rupture and operation also influences mortality rate. The experience of the surgeon is another vital factor in determining mortality rate. PMID:2868942

  11. Predicting the endpoints of earthquake ruptures.

    PubMed

    Wesnousky, Steven G

    2006-11-16

    The active fault traces on which earthquakes occur are generally not continuous, and are commonly composed of segments that are separated by discontinuities that appear as steps in map-view. Stress concentrations resulting from slip at such discontinuities may slow or stop rupture propagation and hence play a controlling role in limiting the length of earthquake rupture. Here I examine the mapped surface rupture traces of 22 historical strike-slip earthquakes with rupture lengths ranging between 10 and 420 km. I show that about two-thirds of the endpoints of strike-slip earthquake ruptures are associated with fault steps or the termini of active fault traces, and that there exists a limiting dimension of fault step (3-4 km) above which earthquake ruptures do not propagate and below which rupture propagation ceases only about 40 per cent of the time. The results are of practical importance to seismic hazard analysis where effort is spent attempting to place limits on the probable length of future earthquakes on mapped active faults. Physical insight to the dynamics of the earthquake rupture process is further gained with the observation that the limiting dimension appears to be largely independent of the earthquake rupture length. It follows that the magnitude of stress changes and the volume affected by those stress changes at the driving edge of laterally propagating ruptures are largely similar and invariable during the rupture process regardless of the distance an event has propagated or will propagate. PMID:17108963

  12. Variable land-level changes at a non-persistent megathrust rupture boundary, Sitkinak Island, Alaska

    NASA Astrophysics Data System (ADS)

    Briggs, R. W.; Engelhart, S. E.; Nelson, A. R.; Kemp, A.; Haeussler, P. J.; Dura, T.

    2013-12-01

    Fault-rupture segmentation models require paleoseismic data to validate inferred rupture boundaries. We examined the southwestern end of the 1964 Mw 9.2 rupture along the Alaska-Aleutian megathrust to test the prehistoric persistence of this historical rupture boundary. On Sitkinak Island in the Trinity Islands, 20 hand-collected cores and tidal outcrops beneath tidal and freshwater marshes reveal five abrupt lithologic contacts that record a mixed record of coseismic uplift (3 events) and subsidence (2 events) in the last ~1000 years. Diatom and foraminiferal assemblages in modern and core material obtained from the southwestern Sitkinak lagoon indicate rapid uplift ca. AD 1788 and just prior to 575 × 65 cal yr and 735 × 65 cal yr; and rapid subsidence in AD 1964 and soon after ~735 cal yr as constrained by 14C ages and tephra correlation. Because the northern coast of Sitkinak was reportedly uplifted in AD 1964 and the island is currently subsiding interseismically above a locked patch of the megathrust, we interpret coseismic subsidence as representing the along-strike transition from elastic uplift to subsidence at the rupture boundary; this implies that the AD 1964 zero uplift isobase crosses the island. Similar behavior has been observed during large megathrust ruptures in Indonesia and the Solomon Islands and is predicted by elastic dislocation models. A sand bed traced inland 1.5 km and bracketed with 14C, 137Cs, and 210Pb ages was most likely deposited by a tsunami associated with megathrust rupture in 1788. Historical records suggest that the AD 1788 rupture extended from the southwest at least 100 km northeast to the Russian settlement at Three Saints Bay near Old Harbor, Kodiak Island. The complicated uplift and subsidence record we observe on Sitkinak Island, interpreted in the context of historical reports of the AD 1788 rupture, is consistent with at least three rupture segmentation models. In Model A, Sitkinak is located at a boundary for 1964- and 1788-type ruptures. A complication with Model A is that it requires 1788-type ruptures to extend at least 100 km into the AD 1964 rupture area. Model B assumes coseismic uplift for large megathrust events on Sitkinak, with subsidence accompanying only updip ruptures or upper-plate deformation. Model B is inconsistent with the observation of coseismic subsidence of the southwestern lagoon in AD 1964. At present we prefer Model C, where megathrust ruptures end or continue near Sitkinak in a complex, and as yet undetermined, pattern. An implication of our field evidence is that seismic hazard models should relax the assumption that the AD 1964 rupture endpoint is persistent.

  13. [Ruptured cerebral artery blister aneurysm].

    PubMed

    Vega Valdés, Pedro; Murias Quintana, Eduardo; Meilán Martínez, Angela; Gutiérrez Morales, Julio; Lopez Garcia, Antonio

    2013-01-01

    We report the case of a young patient with subarachnoid haemorrhage secondary to a ruptured blister-like aneurysm. Since this kind of aneurysms have fragile walls without a well-defined neck, their treatment is difficult. We initially planned the deployment of a flow-diverter stent, but an angiogram obtained after 10 days revealed a morphological change of the aneurysm. Therefore, we finally deployed a conventional stent and introduced 2 micro coils into the point of rupture, obtaining a good morphological result without rebleeding. Follow-up at 1 and 6 months did not observe regrowth of the aneurysm. We offer a brief introduction and discussion of this pathology and its treatment. PMID:23517694

  14. Spontaneous rupture of the ureter

    PubMed Central

    Eken, Alper; Akbas, Tugana; Arpaci, Taner

    2015-01-01

    Spontaneous rupture of the ureter is a very rare condition and usually results from ureteral obstruction by a calculus. Only theoretical mecha­nisms have been proposed and no possible explanation has yet been reported in the literature. Intravenous contrast-enhanced computed tomography is the most informative study with high sensitivity. Treatment should be individualised, and depends on the state of the patient. Minimally invasive endourological procedures with double-J catheter placement and percutaneous drainage offer excellent results. Conservative management with analgesics and antibiotic coverage may be an alternative to surgery. Herein, we present a case of spontaneous rupture of the proximal ureter with no evidence of an underlying pathological condition. PMID:25715862

  15. Spontaneous hepatic rupture in pregnancy.

    PubMed

    Nelson, E W; Archibald, L; Albo, D

    1977-12-01

    Hepatic rupture as a late complication of toxemic pregnancy is a rare yet lethal condition requiring rapid recognition and surgical management. The clinical triad of toxemia, right upper quadrant pain, and sudden hypotension is the diagnostic hallmark of presentation. Most patients present near the time of delivery and are found to have subcapsular hematomas of the right hepatic lobe with free rupture into the peritoneal cavity and resultant exsanguinating hemorrhage. The association of toxemia and disseminated intravascular coagulation with secondary microembolic damage to the liver and other organs has been discussed. Basic surgical principles in the managment of hepatic subcapsular hematomas, and the prolonged postoperative course and frequent complications in these patients have been stressed. PMID:596550

  16. Achilles tendon rupture in badminton.

    PubMed Central

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

    1989-01-01

    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

  17. Micro-analysis of plaque fluid from single-site fasted plaque

    SciTech Connect

    Vogel, G.L.; Carey, C.M.; Chow, L.C.; Tatevossian, A. )

    1990-06-01

    Despite the site-specific nature of caries, nearly all data on the concentration of ions relevant to the level of saturation of plaque fluid with respect to calcium phosphate minerals or enamel are from studies that used pooled samples. A procedure is described for the collection and analysis of inorganic ions relevant to these saturation levels in plaque fluid samples collected from a single surface on a single tooth. Various methods for examining data obtained by this procedure are described, and a mathematical procedure employing potential plots is recommended.

  18. Vulnerable plaque detection by temperature heterogeneity measured with a guidewire system: clinical, intravascular ultrasound and histopathologic correlates.

    PubMed

    Wainstein, Marco; Costa, Marco; Ribeiro, Jorge; Zago, Alcides; Rogers, Campbell

    2007-02-01

    Diagnosing plaque vulnerability may have therapeutic and prognostic implications. We used a heat sensor-tipped thermography guidewire to identify temperature variations in atherosclerotic coronary arteries in patients undergoing stent placement. This study is the first human experience with the ThermoCoil Guidewire (TG). TG consists of a 0.014 inch wire which rotates as it is retracted so as to interrogate the arterial lumen in a helical path. The wire has a temperature sensor in the distal tip with a sensitivity of 0.03 degrees Celcius. In 13 patients presenting with either acute or chronic coronary syndromes as indications for percutaneous coronary intervention, the following parameters were assessed: thermography, intravascular ultrasound (IVUS), angiography and serum markers for inflammation (C-reactive protein) and ischemia (troponin). Directional atherectomy was performed in 2 patients and tissue was analyzed histopathologically. Two patients had unstable angina, 2 had myocardial infarction, and 9 had stable angina as indications for coronary intervention. There were no device-related adverse events or system failures. Thermography was performed on all patients prior to any other intervention. Intra-arterial temperature rises between 0.1 degrees Celcius and 0.3 degrees Celcius were noted in 4 subjects. Intravascular ultrasound findings and atherectomy tissue histology showed correlates of plaque vulnerability in plaques with elevated temperature. In conclusion, thermography using a guidewire-based system can be performed safely, and detected lesions whose IVUS and/or atherectomy findings suggested plaques at high risk for rupture. Further studies will determine the predictive value of thermography or other techniques for assessing plaque composition and risk through noninvasive or invasive means. PMID:17268036

  19. Monoglyceride lipase deficiency modulates endocannabinoid signaling and improves plaque stability in ApoE-knockout mice

    PubMed Central

    Vujic, Nemanja; Schlager, Stefanie; Eichmann, Thomas O.; Madreiter-Sokolowski, Corina T.; Goeritzer, Madeleine; Rainer, Silvia; Schauer, Silvia; Rosenberger, Angelika; Woelfler, Albert; Doddapattar, Prakash; Zimmermann, Robert; Hoefler, Gerald; Lass, Achim; Graier, Wolfgang F.; Radovic, Branislav; Kratky, Dagmar

    2016-01-01

    Background and aims Monoglyceride lipase (MGL) catalyzes the final step of lipolysis by degrading monoglyceride (MG) to glycerol and fatty acid. MGL also hydrolyzes and thereby deactivates 2-arachidonoyl glycerol (2-AG), the most abundant endocannabinoid in the mammalian system. 2-AG acts as full agonist on cannabinoid receptor type 1 (CB1R) and CB2R, which are mainly expressed in brain and immune cells, respectively. Thus, we speculated that in the absence of MGL, increased 2-AG concentrations mediate CB2R signaling in immune cells to modulate inflammatory responses, thereby affecting the development of atherosclerosis. Methods and results We generated apolipoprotein E (ApoE)/MGL double-knockout (DKO) mice and challenged them with Western-type diet for 9 weeks. Despite systemically increased 2-AG concentrations in DKO mice, CB2R-mediated signaling remains fully functional, arguing against CB2R desensitization. We found increased plaque formation in both en face aortae (1.3-fold, p = 0.028) and aortic valve sections (1.5-fold, p = 0.0010) in DKO mice. Interestingly, DKO mice also presented reduced lipid (12%, p = 0.031) and macrophage content (18%, p = 0.061), elevated intraplaque smooth muscle staining (1.4-fold, p = 0.016) and thicker fibrous caps (1.8-fold, p = 0.0032), together with a higher ratio of collagen to necrotic core area (2.5-fold, p = 0.0003) and expanded collagen content (1.6-fold, p = 0.0007), which suggest formation of less vulnerable atherosclerotic plaques. Treatment with a CB2R inverse agonist prevents these effects in DKO mice, demonstrating that the observed plaque phenotype in DKO mice originates from CB2R activation. Conclusion Loss of MGL modulates endocannabinoid signaling in CB2R-expressing cells, which concomitantly affects the pathogenesis of atherosclerosis. We conclude that despite larger lesion size loss of MGL improves atherosclerotic plaque stability. Thus, pharmacological MGL inhibition may be a novel intervention to reduce plaque rupture. PMID:26584135

  20. Selective Inhibition of PI3K/Akt/mTOR Signaling Pathway Regulates Autophagy of Macrophage and Vulnerability of Atherosclerotic Plaque

    PubMed Central

    Zhai, Chungang; Cheng, Jing; Mujahid, Haroon; Wang, Hefeng; Kong, Jing; Yin, Yue; Li, Jifu; Zhang, Yun; Ji, Xiaoping; Chen, Wenqiang

    2014-01-01

    Macrophage infiltration contributes to the instability of atherosclerotic plaques. In the present study, we investigated whether selective inhibition of PI3K/Akt/mTOR signaling pathway can enhance the stability of atherosclerotic plaques by activation of macrophage autophagy. In vitro study, selective inhibitors or siRNA of PI3K/Akt/mTOR pathways were used to treat the rabbit's peritoneal primary macrophage cells. Inflammation related cytokines secreted by macrophages were measured. Ultrastructure changes of macrophages were examined by transmission electron microscope. mRNA or protein expression levels of autophagy related gene Beclin 1, protein 1 light chain 3 II dots (LC3-II) or Atg5-Atg12 conjugation were assayed by quantitative RT-PCR or Western blot. In vivo study, vulnerable plaque models were established in 40 New Zealand White rabbits and then drugs or siRNA were given for 8 weeks to inhibit the PI3K/Akt/mTOR signaling pathway. Intravascular ultrasound (IVUS) was performed to observe the plaque imaging. The ultrastructure of the abdominal aortic atherosclerosis lesions were analyzed with histopathology. RT-PCR or Western blot methods were used to measure the expression levels of corresponding autophagy related molecules. We found that macrophage autophagy was induced in the presence of Akt inhibitor, mTOR inhibitor and mTOR-siRNA in vitro study, while PI3K inhibitor had the opposite role. In vivo study, we found that macrophage autophagy increased significantly and the rabbits had lower plaque rupture incidence, lower plaque burden and decreased vulnerability index in the inhibitors or siRNA treated groups. We made a conclusion that selective inhibition of the Akt/mTOR signal pathway can reduce macrophages and stabilize the vulnerable atherosclerotic plaques by promoting macrophage autophagy. PMID:24599185

  1. Simulations of Transcatheter Aortic Valve Implantation – Implications for Aortic Root Rupture

    PubMed Central

    Wang, Qian; Kodali, Susheel; Primiano, Charles; Sun, Wei

    2014-01-01

    Objectives Aortic root rupture is one of the most severe complications of transcatheter aortic valve implantation (TAVI). The mechanism of this adverse event remains mostly unknown. The purpose of this study was to obtain a better understanding of the biomechanical interaction between the tissue and stent for patients with a high risk of aortic rupture. Methods We simulated the stent deployment process of three TAVI patients with high aortic rupture risk using finite element method. The first case was a retrospective analysis of an aortic rupture case, while the other two cases were prospective studies, which ended with one cancelled procedure and one successful TAVI. Simulation results were evaluated for the risk of aortic root rupture, as well as coronary artery occlusion, and paravalvular leak. Results For Case 1, the simulated aortic rupture location was the same as clinical observations. From the simulation results, it can be seen that the large calcified spot on the interior of the left coronary sinus between coronary ostium and the aortic annulus was pushed by the stent, causing the aortic rupture. For Case 2 and Case 3, predicated results from the simulations were presented to the clinicians at pre-procedure meetings; and they were in agreement with clinician’s observations and decisions. Conclusions Our results indicated that the engineering analysis could provide additional information to help clinicians evaluate complicated, high risk aortic rupture cases. Since a systematic study of a large patient cohort of aortic rupture is currently not available (due to the low occurrence rate) to clearly understand underlying rupture mechanisms, case by case engineering analysis is recommended for evaluating patient-specific aortic rupture risk. PMID:24736808

  2. Are pleural plaques an appropriate endpoint for risk analyses?

    PubMed

    Maxim, L Daniel; Niebo, Ronald; Utell, Mark J

    2015-01-01

    This review summarizes the literature on the relation between the development of pleural plaques and non-malignant and malignant disease in cohorts exposed to asbestos and other fibers. The available evidence indicates that, absent any other pleural disease, the presence of pleural plaques does not result in respiratory symptoms or clinically significant impacts on lung function. For certain types of asbestos, the development of pleural plaques is statistically correlated with malignant disease, but the evidence is consistent with the hypothesis that pleural plaques without other pleural disease are a marker of exposure, rather than an independent risk factor. Pleural plaques have also developed in cohorts exposed to other fibers that have not proven to be carcinogenic. Risk analyses should be based on the avoidance of known adverse conditions, rather than pleural plaques per se. PMID:26075933

  3. Computer Simulations of Atherosclerotic Plaque Growth in Coronary Arteries

    PubMed Central

    Liu, Biyue; Tang, Dalin

    2011-01-01

    A three dimensional mathematical model with a linear plaque growth function was developed to investigate the geometrical adaptation of atherosclerotic plaques in coronary arteries and study the influences of flow wall shear stress (WSS), blood viscosity and the inlet flow rate on the growth of atherosclerotic plaques using computational plaque growth simulations. The simulation results indicated that the plaque wall thickness at the neck of the stenosis increased at a decreasing rate in the atherosclerosis progression. The simulation results also showed a strong dependence of the plaque wall thickness increase on the blood viscosity and the inlet flow rate. The progression rate in a coronary artery was lower with a higher inlet velocity flow rate and higher with a smaller value of the blood viscosity. PMID:21141673

  4. Review of diagnostic plaque reduction neutralization tests for flavivirus infection.

    PubMed

    Maeda, Akihiko; Maeda, Junko

    2013-01-01

    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

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

    USGS Publications Warehouse

    Harris, R.A.

    2004-01-01

    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.

  6. Congenital Milia En Plaque on Scalp

    PubMed Central

    Ghosh, Sangita; Sangal, Shikha

    2015-01-01

    Milia en plaque is a rare disease entity characterized by confluence of multiple keratin-filled cysts resulting from the obstruction of hair follicle without any preceding primary dermatosis. Fewer than 40 cases have been reported so far in dermatological literature, and most cases are described to occur in adults and in the peri-auricular area. We describe a case of congenital MEP on scalp of a five-year-old boy with a blaschkoid extension into posterior nuchal area. This case report claims its uniqueness because of the unusual site and congenital presentation. PMID:25657433

  7. Stability Analysis of a Model of Atherosclerotic Plaque Growth

    PubMed Central

    Reddy, Sushruth; Seshaiyer, Padmanabhan

    2015-01-01

    Atherosclerosis, the formation of life-threatening plaques in blood vessels, is a form of cardiovascular disease. In this paper, we analyze a simplified model of plaque growth to derive physically meaningful results about the growth of plaques. In particular, the main results of this paper are two conditions, which express that the immune response increases as LDL cholesterol levels increase and that diffusion prevails over inflammation in a healthy artery. PMID:25883675

  8. Dosimetric Benefit of a New Ophthalmic Radiation Plaque

    SciTech Connect

    Marwaha, Gaurav; Cleveland Clinic Foundation, Cleveland, Ohio ; Wilkinson, Allan; Cleveland Clinic Foundation, Cleveland, Ohio ; Bena, James; Cleveland Clinic Foundation, Cleveland, Ohio ; Macklis, Roger; Cleveland Clinic Foundation, Cleveland, Ohio ; Singh, Arun D.; Department of Ophthalmic Oncology, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio; Cleveland Clinic Foundation, Cleveland, Ohio

    2012-12-01

    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.

  9. Multimodality imaging of carotid atherosclerotic plaque: Going beyond stenosis

    PubMed Central

    Hingwala, Divyata; Kesavadas, Chandrasekharan; Sylaja, Padmavathy N; Thomas, Bejoy; Kapilamoorthy, Tirur Raman

    2013-01-01

    Apart from the degree of stenosis, the morphology of carotid atherosclerotic plaques and presence of neovascularization are important factors that may help to evaluate the risk and ‘vulnerability’ of plaques and may also influence the choice of treatment. In this article, we aim to describe the techniques and imaging findings on CTA, high resolution MRI and contrast enhanced ultrasound in the evaluation of carotid atherosclerotic plaques. We also discuss a few representative cases from our institute with the related clinical implications. PMID:23986615

  10. Patterns of Therapeutic Alliance: Rupture-Repair Episodes in Prolonged Exposure for PTSD

    PubMed Central

    McLaughlin, AnnaMaria Aguirre; Keller, Stephanie M.; Feeny, Norah C.; Youngstrom, Eric A.; Zoellner, Lori A.

    2014-01-01

    Objective To better understand the role of therapeutic alliance in PTSD treatment, we examined patterns of and shifts in alliance. First, we identified individuals with repaired ruptures, unrepaired ruptures, and no ruptures in alliance. Then, we explored group differences in these alliance events for clients with common clinical correlates (i.e., co-occurring depression and childhood abuse history) and whether or not the presence of these events influenced treatment outcome. Method At pre-treatment, clients (N = 116); 76.1% female; 66% Caucasian; age M = 36.7 years (SD = 11.3) completed measures assessing PTSD diagnosis and severity (PTSD Symptom Scale Interview and Self-Report), depression diagnosis and severity (Structured Clinical Interview for DSM-IV and Beck Depression Inventory), and trauma history. During ten weeks of prolonged exposure therapy, alliance (California Psychotherapy Alliance Scale) measures were completed. At post-treatment, PTSD and depression were re-assessed. Results Ruptures in alliance were quite common (46%). No significant differences emerged in the frequency of repaired ruptures, unrepaired ruptures, or no ruptures between those with and without co-occurring MDD, X2 (2, N = 82) = 2.69, p =. 26, or those with and without a history of childhood abuse, X2 (2, N = 81) = 0.57, p = .75. Unrepaired ruptures predicted worse treatment outcome (β = .45, p = .001). Conclusions The current study underscores the importance of attending to discontinuities in alliance throughout treatment. PMID:24188510

  11. The role of Randall plaques on kidney stone formation

    PubMed Central

    2014-01-01

    Randall’s plaque is microscopically a plaque of calcium deposited in the interstitial tissue of the renal papilla. These plaques are thought to serve as a nidus for urinary stone formation. Large amounts of Randall’s plaque are unique to idiopathic calcium oxalate stone formers. Although Randall’s plaques can be found in other stone formers, only in idiopathic calcium oxalate stone formers, the detailed mechanism of stone overgrow on plaque was thoroughly studied. Calcification is invariably located in the basement membrane of the loops of Henle and from there plaques spread through the interstitium toward urothelium. Within the basement membrane, mineral deposits are individual laminated particles in which zones of crystal and organic matrix overlay each other. In the interstitium, the particles appear to fuse on the collagen bundles to form a syncytium of crystal islands in an organic sea. By loss of integrity of urothelium, regions of plaque are exposed to urine. The exposed surface will touch and be covered by molecules of urine origin, including osteopontin, Tamm Horsfall protein, and crystals formed under urine supersaturations, resulting in a ribbon of alternating matrix and crystal. Eventually crystallization escapes from matrix modulation and crystals extend outward into the space of urine and begin to form a calcium oxalate stone proper. Randall’s plaque plays an important role and is prerequisite of kidney stone formation in idiopathic calcium oxalate stone formers. PMID:26816774

  12. Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses

    PubMed Central

    Lanvin, Thomas; Conkey, Donald B.; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-01-01

    We perform subsurface ablation of atherosclerotic plaque using ultrafast pulses. Excised mouse aortas containing atherosclerotic plaque were ablated with ultrafast near-infrared (NIR) laser pulses. Optical coherence tomography (OCT) was used to observe the ablation result, while the physical damage was inspected in histological sections. We characterize the effects of incident pulse energy on surface damage, ablation hole size, and filament propagation. We find that it is possible to ablate plaque just below the surface without causing surface damage, which motivates further investigation of ultrafast ablation for subsurface atherosclerotic plaque removal. PMID:26203381

  13. 14. DETAIL VIEW OF COMMEMORATIVE PLAQUE AND FINIAL, NORTH END ...

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

    14. DETAIL VIEW OF COMMEMORATIVE PLAQUE AND FINIAL, NORTH END SPAN - East Bloomsburg Bridge, Spanning Susquehanna River at Pennsylvania Route 487 (Legislative Route 283), Bloomsburg, Columbia County, PA

  14. DETAIL OF PLAQUE WITH ADDITIONAL DESIGN AND CONSTRUCTION INFORMATION, SOUTHEAST ...

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

    DETAIL OF PLAQUE WITH ADDITIONAL DESIGN AND CONSTRUCTION INFORMATION, SOUTHEAST ABUTMENT - Connecticut Avenue Bridge, Spans Rock Creek & Potomac Parkway at Connecticut Avenue, Washington, District of Columbia, DC

  15. Early second trimester uterine scar rupture

    PubMed Central

    Bharatnur, Sunanda; Hebbar, Shripad; G, Shyamala

    2013-01-01

    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

  16. Early second trimester uterine scar rupture.

    PubMed

    Bharatnur, Sunanda; Hebbar, Shripad; Shyamala, G

    2013-01-01

    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

  17. Photolichenoid plaques with associated vitiliginous pigmentary changes.

    PubMed

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

    2011-01-01

    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

  18. Assessment of plaque assay methods for alphaviruses.

    PubMed

    Juarez, Diana; Long, Kanya C; Aguilar, Patricia; Kochel, Tadeusz J; Halsey, Eric S

    2013-01-01

    Viruses from the Alphavirus genus are responsible for numerous arboviral diseases impacting human health throughout the world. Confirmation of acute alphavirus infection is based on viral isolation, identification of viral RNA, or a fourfold or greater increase in antibody titers between acute and convalescent samples. In convalescence, the specificity of antibodies to an alphavirus may be confirmed by plaque reduction neutralization test. To identify the best method for alphavirus and neutralizing antibody recognition, the standard solid method using a cell monolayer overlay with 0.4% agarose and the semisolid method using a cell suspension overlay with 0.6% carboxymethyl cellulose (CMC) overlay were evaluated. Mayaro virus, Una virus, Venezuelan equine encephalitis virus (VEEV), and Western equine encephalitis virus (WEEV) were selected to be tested by both methods. The results indicate that the solid method showed consistently greater sensitivity than the semisolid method. Also, a "semisolid-variant method" using a 0.6% CMC overlay on a cell monolayer was assayed for virus titration. This method provided the same sensitivity as the solid method for VEEV and also had greater sensitivity for WEEV titration. Modifications in plaque assay conditions affect significantly results and therefore evaluation of the performance of each new assay is needed. PMID:23085307

  19. Plaque-type morphea in children.

    PubMed

    St?nescu, Ligia; Vâlcea, Alina; Popescu, Carmen Florina; Niculescu, Carmen Elena; Ciobanu, O; C?lin, G

    2010-01-01

    We present the case of a girl, aged 8-year-old, with a history of acrocyanosis and repeated respiratory infections with beta-hemolytic streptococcus, which was consulted for the presence of skin lesions in the right buttock area. Clinical examination showed, in the right buttock region, an oval plaque with a diameter about 12 cm, hard, well defined, with irregular outline. The biopsy was performed and it revealed typical aspects of plaque-type morphea. The epidermis was mostly atrophic, with areas of ridge reduction; an important proliferation of collagen fibers within superficial and deep dermis and an abundant lymphocytic inflammatory infiltrate throughout the dermal thickness reaching hypodermic level and infiltrating it. General treatment consisted of antibiotics; vitamin E; local treatment with topical cortisone; analogues of vitamin D3 to which we associated topical adjuvants with repairing and healing role applied to the biopsied area. Evolution was favorable after three months of treatment, with obvious improvement of skin lesions; skin became more elastic and the purple red contour ring disappeared. PMID:20809038

  20. Investigation of cryogenic rupture disc design

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    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.

  1. Spontaneous rupture of a splenotic nodule.

    PubMed Central

    Lanigan, D. J.

    1990-01-01

    A case is presented of spontaneous rupture of splenic tissue occurring 14 years after a splenectomy was carried out for trauma. Spontaneous rupture of a splenotic nodule has not previously been described and it may be added to the list of causes of spontaneous haemoperitoneum. The incidence and function of residual splenic tissue are briefly discussed and other causes of splenic rupture are outlined. PMID:2267217

  2. Neck curve polynomials in neck rupture model

    SciTech Connect

    Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul

    2012-06-06

    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.

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

    SciTech Connect

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

    2010-11-23

    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 cortex and hippocampus using X-ray fluorescence microscopy (XFM). We found that iron in the cortex was 34% higher than age-matched controls at an early stage, corresponding to the commencement of plaque formation. The elevated iron was not associated with the amyloid plaques. Interestingly, none of the metal ions were elevated in the amyloid plaques until the latest time point (56 weeks), where only the Zn content was significantly elevated by 38%. Since neuropathological changes in human Alzheimer's disease are presumed to occur years before the first cognitive symptoms appear, quantification of brain iron content could be a powerful marker for early diagnosis of Alzheimer's disease.

  4. Optimal parameters for near infrared fluorescence imaging of amyloid plaques in Alzheimer's disease mouse models

    NASA Astrophysics Data System (ADS)

    Raymond, S. B.; Kumar, A. T. N.; Boas, D. A.; Bacskai, B. J.

    2009-10-01

    Amyloid-? plaques are an Alzheimer's disease biomarker which present unique challenges for near-infrared fluorescence tomography because of size (<50 µm diameter) and distribution. We used high-resolution simulations of fluorescence in a digital Alzheimer's disease mouse model to investigate the optimal fluorophore and imaging parameters for near-infrared fluorescence tomography of amyloid plaques. Fluorescence was simulated for amyloid-targeted probes with emission at 630 and 800 nm, plaque-to-background ratios from 1-1000, amyloid burden from 0-10%, and for transmission and reflection measurement geometries. Fluorophores with high plaque-to-background contrast ratios and 800 nm emission performed significantly better than current amyloid imaging probes. We tested idealized fluorophores in transmission and full-angle tomographic measurement schemes (900 source-detector pairs), with and without anatomical priors. Transmission reconstructions demonstrated strong linear correlation with increasing amyloid burden, but underestimated fluorescence yield and suffered from localization artifacts. Full-angle measurements did not improve upon the transmission reconstruction qualitatively or in semi-quantitative measures of accuracy; anatomical and initial-value priors did improve reconstruction localization and accuracy for both transmission and full-angle schemes. Region-based reconstructions, in which the unknowns were reduced to a few distinct anatomical regions, produced highly accurate yield estimates for cortex, hippocampus and brain regions, even with a reduced number of measurements (144 source-detector pairs).

  5. Quantifying uncertainty in earthquake rupture models

    NASA Astrophysics Data System (ADS)

    Page, Morgan T.

    Using dynamic and kinematic models, we analyze the ability of GPS and strong-motion data to recover the rupture history of earthquakes. By analyzing the near-source ground-motion generated by earthquake ruptures through barriers and asperities, we determine that both the prestress and yield stress of a frictional inhomogeneity can be recovered. In addition, we find that models with constraints on rupture velocity have less ground motion than constraint-free, spontaneous dynamic models with equivalent stress drops. This suggests that kinematic models with such constraints overestimate the actual stress heterogeneity of earthquakes. We use GPS data from the well-recorded 2004 Mw6.0 Parkfield Earthquake to further probe uncertainties in kinematic models. We find that the inversion for this data set is poorly resolved at depth and near the edges of the fault. In such an underdetermined inversion, it is possible to obtain spurious structure in poorly resolved areas. We demonstrate that a nonuniform grid with grid spacing matching the local resolution length on the fault outperforms small uniform grids, which generate spurious structure in poorly resolved regions, and large uniform grids, which lose recoverable information in well-resolved areas of the fault. The nonuniform grid correctly averages out large-scale structure in poorly resolved areas while recovering small-scale structure near the surface. In addition to probing model uncertainties in earthquake source models, we also examine the effect of model uncertainty in Probabilistic Seismic Hazard Analysis (PSHA). While methods for incorporating parameter uncertainty of a particular model in PSHA are well-understood, methods for incorporating model uncertainty are more difficult to implement due to the high degree of dependence between different earthquake-recurrence models. We show that the method used by the 2002 Working Group on California Earthquake Probabilities (WGCEP-2002) to combine the probability distributions given by multiple earthquake recurrence models has several adverse effects on their result. In particular, WGCEP-2002 uses a linear combination of the models which ignores model dependence and leads to large uncertainty in the final hazard estimate. In addition to analyzing current statistical problems, we present alternative methods for rigorously incorporating model uncertainty into PSHA.

  6. Induced rupture of vesicles adsorbed on glass by pore formation at the surface-bilayer interface.

    PubMed

    Kataoka-Hamai, Chiho; Yamazaki, Tomohiko

    2015-02-01

    Supported lipid bilayers (SLBs) are often formed by spontaneous vesicle rupture and fusion on a solid surface. A well-characterized rupture mechanism for isolated vesicles is pore nucleation and expansion in the solution-exposed nonadsorbed area. In contrast, pore formation in the adsorbed bilayer region has not been investigated to date. In this work, we studied the detailed mechanisms of asymmetric rupture of giant unilamellar vesicles (GUVs) adsorbed on glass using fluorescence microscopy. Asymmetric rupture is the pathway where a rupture pore forms in a GUV near the edge of the glass-bilayer interface with high curvature and then expansion of the pore yields a planar bilayer patch. We show that asymmetric rupture occasionally resulted in SLB patches bearing a defect pore. The defect formation probability depended on lipid composition, salt concentration, and pH. Approximately 40% of negatively charged GUVs under physiological conditions formed pore-containing SLB patches, while negatively charged GUVs at low salt concentration or pH 4.0 and positively charged GUVs exhibited a low probability of defect inclusion. The edge of the defect pore was either in contact with (on-edge) or away from (off-edge) the edge of the planar bilayer. On-edge pores were predominantly formed over off-edge defects. Pores initially formed in the glass-adsorbed region before rupture, most frequently in close contact with the edge of the adsorbed region. When a pore formed near the edge of the adsorbed area or when the edge of a pore reached that of the adsorbed area by pore expansion, asymmetric rupture was induced from the defect site. These induced rupture mechanisms yielded SLB patches with an on-edge pore. In contrast, off-edge pores were produced when defect pore generation and subsequent vesicle rupture were uncoupled. The current results demonstrate that pore formation in the surface-adsorbed region of GUVs is not a negligible event. PMID:25575280

  7. New low-viscosity overlay medium for viral plaque assays

    PubMed Central

    Matrosovich, Mikhail; Matrosovich, Tatyana; Garten, Wolfgang; Klenk, Hans-Dieter

    2006-01-01

    Background Plaque assays in cell culture monolayers under solid or semisolid overlay media are commonly used for quantification of viruses and antiviral substances. To overcome the pitfalls of known overlays, we tested suspensions of microcrystalline cellulose Avicel RC/CL™ as overlay media in the plaque and plaque-inhibition assay of influenza viruses. Results Significantly larger plaques were formed under Avicel-containing media, as compared to agar and methylcellulose (MC) overlay media. The plaque size increased with decreasing Avicel concentration, but even very diluted Avicel overlays (0.3%) ensured formation of localized plaques. Due to their low viscosity, Avicel overlays were easier to use than methylcellulose overlays, especially in the 96-well culture plates. Furthermore, Avicel overlay could be applied without prior removal of the virus inoculum thus facilitating the assay and reducing chances of cross-contamination. Using neuraminidase inhibitor oseltamivir carboxylate, we demonstrated applicability of the Avicel-based plaque reduction assay for testing of antiviral substances. Conclusion Plaque assay under Avicel-containing overlay media is easier, faster and more sensitive than assays under agar- and methylcellulose overlays. The assay can be readily performed in a 96-well plate format and seems particularly suitable for high-throughput virus titrations, serological studies and experiments on viral drug sensitivity. It may also facilitate work with highly pathogenic agents performed under hampered conditions of bio-safety labs. PMID:16945126

  8. Computational Fluid Dynamics Simulations of Hemodynamics in Plaque Erosion

    PubMed Central

    Campbell, Ian C.; Timmins, Lucas H.; Giddens, Don P.; Virmani, Renu; Veneziani, Alessandro; Rab, S. Tanveer; Samady, Habib; McDaniel, Michael C.; Finn, Aloke V.; Taylor, W. Robert; Oshinski, John N.

    2013-01-01

    Purpose We investigated whether local hemodynamics were associated with sites of plaque erosion and hypothesized that patients with plaque erosion have locally elevated WSS magnitude in regions where erosion has occurred. Methods We generated 3D, patient-specific models of coronary arteries from biplane angiographic images in 3 human patients with plaque erosion diagnosed by optical coherence tomography (OCT). Using computational fluid dynamics, we simulated pulsatile blood flow and calculated both wall shear stress (WSS) and oscillatory shear index (OSI). We also investigated anatomic features of plaque erosion sites by examining branching and local curvature in x-ray angiograms of barium-perfused autopsy hearts. Results Neither high nor low magnitudes of mean WSS were associated with sites of plaque erosion. OSI and local curvature were also not associated with erosion. Anatomically, 8 of 13 hearts had a nearby bifurcation upstream of the site of plaque erosion. Conclusions This study provides preliminary evidence that neither hemodynamics nor anatomy are predictors of plaque erosion, based upon a very unique dataset. Our sample sizes are small, but this dataset suggests that high magnitudes of wall shear stress, one potential mechanism for inducing plaque erosion, are not necessary for erosion to occur. PMID:24223678

  9. Characterization of bacteriophage communities and CRISPR profiles from dental plaque

    PubMed Central

    2014-01-01

    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

  10. Traumatic bilateral Achilles tendon rupture in a young athlete treated with percutaneous tenorrhaphy

    PubMed Central

    MACERA, ARMANDO; CARULLI, CHRISTIAN; MATASSI, FABRIZIO; VENEZIANI, CARLO; INNOCENTI, MASSIMO

    2015-01-01

    While rupture of the Achilles tendon is one of the most frequent injuries sustained in sports and physical activity, bilateral Achilles tendon rupture is uncommon. We present the case of a 33-year-old man who sustained a bilateral Achilles tendon rupture in the absence of predisposing factors. The lesions were managed by percutaneous tenorrhaphy and casting. Six months after surgery he was able to return to his daily-life activities and to perform light sports activity. The Authors review the current literature on the management of this rare condition in young people, with or without risk factors. PMID:26904529

  11. Are herbal mouthwash efficacious over chlorhexidine on the dental plaque?

    PubMed Central

    Gupta, Devanand; Nayan, Swapna; Tippanawar, Harshad K.; Patil, Gaurav I.; Jain, Ankita; Momin, Rizwan K.; Gupta, Rajendra Kumar

    2015-01-01

    Aim: To compare the effect of herbal extract mouthwash and chlorhexidine mouthwash on the dental plaque level. Materials and Methods: The subjects (60 healthy medical students aged ranges between 20 and 25 years) were randomly divided into two groups, that is, the herbal group and the chlorhexidine gluconate mouthwash group. The data were collected at the baseline and 3 days. The plaque was disclosed using erythrosine disclosing agent and their scores were recorded using the Quigley and Hein plaque index modified by Turesky-Gilmore-Glickman. Statistical analysis was carried out later to compare the effect of all the two groups. Results: Our result showed that the chlorhexidine group shows a greater decrease in plaque score followed by herbal extract, but the result was statistically insignificant. Conclusion: The results indicate that herbal mouthwash may prove to be an effective agent owing to its ability to reduce plaque level, especially in low socioeconomic strata. PMID:26130940

  12. Lifting the Silver Flakes: The Pathogenesis and Management of Chronic Plaque Psoriasis

    PubMed Central

    Chong, Heng T.; Cowin, Allison J.

    2013-01-01

    Psoriasis is a common chronic inflammatory skin condition in which patients suffer from mild to chronic plaque skin plaques. The disease manifests through an excessive inflammatory response in the skin due to complex interactions between different genetic and environmental factors. Psoriasis can affect the physical, emotional, and psychosocial well-being of patients, and currently there is no cure with treatments focusing primarily on the use of anti-inflammatory agents to control disease symptoms. Traditional anti-inflammatory agents can cause immunosuppression and adverse systemic effects. Further understanding of the disease has led to current areas of research aiming at the development of selective molecular targets to suppress the pathogenic immune responses. PMID:24062996

  13. Automated coronary CT angiography plaque-lumen segmentation

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    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.

  14. Second-Trimester Uterine Rupture: Lessons Learnt

    PubMed Central

    F. ABDULWAHAB, Dalia; ISMAIL, Hamizah; NUSEE, Zalina

    2014-01-01

    Uterine rupture is a rare life-threatening complication. It mainly occurs in the third trimester of pregnancy and is rarely seen during the first or second trimesters. Our centre experienced three important cases of uterine rupture. First case: spontaneous uterine rupture at 14 weeks of pregnancy, which was diagnosed at autopsy. It was misled by the ultrasound finding of an intrauterine pregnancy, and searching for other non-gynaecological causes delayed the urgent obstetric surgical management. Second case: ruptured uterus at 24 weeks following medical termination due to foetal anomaly. It was diagnosed only at laparotomy indicated for failed medical termination and chorioamnionitis. Third case: uterine rupture at 21 weeks of pregnancy in a patient with gastroenterology symptoms. In these reports, we have discussed the various risk factors, presentations, course of events and difficulties in diagnosing uterine rupture. The study concludes that the clinical presentation of uterine ruptures varies. It occurs regardless of gestational age. Ultrasound findings of intrauterine pregnancy with free fluid do not exclude uterine rupture or ectopic pregnancy. Searching for non-gynaecological causes in such clinical presentations might delay crucial surgical intervention, which leads to unnecessary morbidity, mortality or loss of obstetrics function. PMID:25977625

  15. Do buried-rupture earthquakes trigger less landslides than surface-rupture earthquakes for reverse faults?

    NASA Astrophysics Data System (ADS)

    Xu, Chong

    2014-07-01

    Gorum et al. (2013, Geomorphology 184, 127-138) carried out a study on inventory compilation and statistical analyses of landslides triggered by the 2010 Mw 7.0 Haiti earthquake. They revealed that spatial distribution patterns of these landslides were mainly controlled by complex rupture mechanism and topography. They also suggested that blind-rupture earthquakes trigger fewer landslides than surface-rupture earthquakes on thrust reverse faults. Although a few lines of evidence indicate that buried-rupture earthquakes might trigger fewer landslides than surface-rupture earthquakes on reverse faults, more careful comparisons and analyses indicate that it is not always true. Instead, some cases show that a buried-rupture earthquake can trigger a larger quantity of landslides that are distributed in a larger area, whereas surface-rupture earthquakes can trigger larger but a fewer landslides distributed in a smaller area.

  16. Microglial response to amyloid plaques in APPsw transgenic mice.

    PubMed Central

    Frautschy, S. A.; Yang, F.; Irrizarry, M.; Hyman, B.; Saido, T. C.; Hsiao, K.; Cole, G. M.

    1998-01-01

    Microglial activation is central to the inflammatory response in Alzheimer's Disease (AD). A recently described mouse line, Tg(HuAPP695.K670N/M671L)2576, expressing human amyloid precursor protein with a familial AD gene mutation, age-related amyloid deposits, and memory deficits, was found to develop a significant microglial response using Griffonia simplicifolia lectin or phosphotyrosine probe to identify microglia Both Griffonia simplicifolia lectin and phosphotyrosine staining showed increased numbers of intensely labeled, often enlarged microglia clustered in and around plaques, consistent with microglial activation related to beta-amyloid formation. Using quantitative image analysis of coronal phosphotyrosine-immunostained sections, transgene-positive 10- to 16-month-old, hemizygous, hybrid Tg2576 (APPsw) animals showed significantly increased microglial density and size in plaque-forming areas of hippocampus and frontal, entorhinal, and occipital cortex. Quantitative analysis of microglia as a function of distance from the center of plaques (double labeled for A beta peptide and microglia) revealed highly significant, two- to fivefold elevations in microglial number and area within plaques compared with neighboring regions. Tg2576 beta-amyloid-plaque-forming mice should be a useful system for assessing the consequences of the microglial-mediated inflammatory response to beta-amyloid and developing anti-inflammatory therapeutic strategies for Alzheimer's disease. These results provide the first quantitative link between beta-amyloid plaque formation and microglial activation in an animal model with neuritic plaques and memory deficits. Images Figure 1 Figure 2 PMID:9422548

  17. Metal plaque on reeds from an Acid mine drainage site.

    PubMed

    Guo, Lin; Cutright, Teresa J

    2015-05-01

    Studies were conducted to investigate the interactions among rhizosphere microorganisms, plaque formation, and metal accumulation in reeds [ (Cav.) Trin. ex Steud.] grown in an acid mine drainage-contaminated field. We found that Fe(II)-oxidizing bacteria (Fe(II)OB] played a key role in Fe plaque formation and pH decrease. The kinetics of Fe plaque formation were related to the abundance of rhizosphere Fe(II)OB, which mediated 66.0 to 93.3% Fe(II) oxidation. The Fe(II) concentration decreased from 14.24 to 0.94 mg L in nonsterile samples, with the most abundant Fe(II)OB activity (5.64 ± 3.83 × 10 colony-forming units g) after 2 d, and pH decreased from 2.91 to 2.50. The amount of metal plaque was also positively correlated with metal levels in soil. No significant correlations were found between Fe, Mn, and Al concentration in the plaque. Reeds sequestered Al in the aboveground tissues, and Mn and Al were stored in the roots and rhizomes. Metal plaque did not affect the Mn uptake but inhibited the translocation of Fe and Al in reeds. To increase the phytoremediation efficiency of Fe, Mn, and Al from the acid mine drainage-contaminated site, further research may be needed to inhibit the Fe(II)OB growth and reduce the metal plaque formation, thereby increasing the metal accumulation in reeds. PMID:26024266

  18. CD44 Targeting Magnetic Glyconanoparticles for Atherosclerotic Plaque Imaging

    PubMed Central

    El-Dakdouki, Mohammad H.; El-Boubbou, Kheireddine; Kamat, Medha; Huang, Ruiping; Abela, George S.; Kiupel, Matti; Zhu, David C.; Huang, Xuefei

    2013-01-01

    Purpose The cell surface adhesion molecule CD44 plays important roles in the initiation and development of atherosclerotic plaques. We aim to develop nanoparticles that can selectively target CD44 for the non-invasive detection of atherosclerotic plaques by magnetic resonance imaging. Methods Magnetic glyco-nanoparticles with hyaluronan immobilized on the surface have been prepared. The binding of these nanoparticles with CD44 in vitro was evaluated by enzyme linked immunosorbent assay, flow cytometry and confocal microscopy. In vivo magnetic resonance imaging of plaques was performed on an atherosclerotic rabbit model. Results The magnetic glyconanoparticles can selectively bind CD44. In T2* weighted magnetic resonance images acquired in vivo, significant contrast changes in aorta walls were observed with a very low dose of the magnetic nanoparticles, allowing the detection of atherosclerotic plaques. Furthermore, imaging could be performed without significant delay after probe administration. The selectivity of hyaluronan nanoparticles in plaque imaging was established by several control experiments. Conclusions Magnetic nanoparticles bearing surface hyaluronan enabled the imaging of atherosclerotic plaques in vivo by magnetic resonance imaging. The low dose of nanoparticles required, the possibility to image without much delay and the high biocompatibility are the advantages of these nanoparticles as contrast agents for plaque imaging. PMID:23568520

  19. Systematic review of pleural plaques and lung function

    PubMed Central

    Kerper, Laura E.; Lynch, Heather N.; Zu, Ke; Tao, Ge; Utell, Mark J.

    2015-01-01

    Abstract Context US EPA proposed a Reference Concentration for Libby amphibole asbestos based on the premise that pleural plaques are adverse and cause lung function deficits. Objective We conducted a systematic review to evaluate whether there is an association between pleural plaques and lung function and ascertain whether results were dependent on the method used to identify plaques. Methods Using the PubMed database, we identified studies that evaluated pleural plaques and lung function. We assessed each study for quality, then integrated evidence and assessed associations based on the Bradford Hill guidelines. We also compared the results of HRCT studies to those of X-ray studies. Results We identified 16 HRCT and 36 X-ray studies. We rated six HRCT and 16 X-ray studies as higher quality based on a risk-of-bias analysis. Half of the higher quality studies reported small but statistically significant mean lung function decrements associated with plaques. None of the differences were clinically significant. Many studies had limitations, such as inappropriate controls and/or insufficient adjustment for confounders. There was little consistency in the direction of effect for the most commonly reported measurements. X-ray results were more variable than HRCT results. Pleural plaques were not associated with changes in lung function over time in longitudinal studies. Conclusion The weight of evidence indicates that pleural plaques do not impact lung function. Observed associations are most likely due to unidentified abnormalities or other factors. PMID:25518994

  20. Factors Contributing to Multi-Segment Rupture in the 2010 M7.1 Darfield, New Zealand, Earthquake

    NASA Astrophysics Data System (ADS)

    Aagaard, B.; Williams, C. A.; Fry, B.

    2014-12-01

    We use dynamic prescribed slip (kinematic) modeling to examine the factors contributing to multi-segment rupture in the 2010 M7.1 Darfield earthquake. We consider fault geometry and slip distributions from inversions by Beavan et al. (2012) based on geodetic observations and by Elliott et al. (2012) based on geodetic and teleseismic observations. We invert for subevent origin times using strong-motion records and find complex rupture propagation across multiple fault segments. Our inversions suggest that the rupture began on one or two secondary faults with reverse/oblique slip near the hypocenter, consistent with the GNS first motion mechanism. The primary bilateral strike-slip rupture of the Greendale fault, consistent with centroid moment tensor solutions, occurred about 9-10 seconds after the origin time. The strong-motion records provide poor constraints on the timing of rupture of the reverse Hororata fault, which may have occurred about 16-17 seconds after the origin time. Denser strong-motion instrumentation would have provided stronger constraints on the timing of the complex rupture. The relative orientation of the regional stress field and the faulting regime explain the sense of motion and loading of these fault segments. Additionally, dynamic stress changes also created favorable conditions for triggering of the main rupture on the Greendale fault. Current work focuses on evaluating how well the UCERF3 (USGS Open File Report 2013-1165) criteria for forecasting multi-segment ruptures in California apply to this complex rupture in New Zealand.

  1. Spontaneous rupture of the spleen operated in gynecological unit mistaken for ruptured hemorrhagic ovarian cyst: total splenectomy

    PubMed Central

    Eko, Filbert Eko; Fouelifack, Florent Ymele; de Paul, Elanga Vincent

    2014-01-01

    Spontaneous splenic rupture is always neglected when consulting acute abdominal pains in gynecological emergencies. It constitutes about 1% of all splenic ruptures and can be managed by abstention, surgery or embolization. We present the case of a young lady who was diagnosed of spontaneous rupture during surgery that was mistaken for ruptured hemorrhagic ovarian cyst and finally treated by total splenectomy. The pre-operative work up was absolute for a rupturred hemorrhagic cyst and secondariy for a ruptured ectopic gestation. PMID:25918564

  2. Changes in atherosclerotic plaques induced by inhalation of diesel exhaust

    PubMed Central

    Bai, Ni; Kido, Takashi; Suzuki, Hisashi; Yang, Grace; Kavanagh, Terrance J.; Kaufman, Joel D.; Rosenfeld, Michael E.; van Breemen, Cornelis; van Eeden, Stephan F.

    2015-01-01

    Objective Exposure to particulate matter air pollution may be an independent risk factor for cardiovascular morbidity and mortality; however, the biological mechanisms are unclear. We hypothesize that exposure to diesel exhaust (DE), an important source of traffic-related particulate air pollution, promotes changes of atherosclerotic plaque component that may lead to plaque vulnerability. Methods and results 30-week old ApoE knockout mice fed with regular chow inhaled DE (at 200 ?g/m3 of particulate) or filtered-air (control) for 7 weeks (6 h/day, 5 days/week) (12 mice/group). Total number of alveolar macrophages (p < 0.01) and alveolar macrophages positive for particles (p < 0.0001) were more than 8-fold higher after DE inhalation than the control. DE inhalation caused 1.5 to 3-fold increases in plaque lipid content (p<0.02), cellularity (p<0.02), foam cell formation (p<0.04), and smooth muscle cell content (p<0.05). The expression of oxidative stress markers, iNOS, CD36, and nitrotyrosine was significantly increased by 1.5 to 2-fold in plaques, with enhanced systemic lipid and DNA oxidation (p<0.02). Increased foam cells and the expression of iNOS (R2 = 0.72, p = 0.0081) and CD36 (R2 = 0.49, p = 0.015) in plaques were positively correlated with the magnitude of DE exposure. Conclusions Exposure to DE promotes changes in atherosclerotic plaques characteristic of unstable vulnerable plaques. Increased systemic and plaque oxidative stress markers suggest that these changes in plaques could be due to DE-induced oxidative stress. PMID:21435644

  3. Cloacal exstrophy: prenatal diagnosis before rupture of the cloacal membrane.

    PubMed

    Langer, J C; Brennan, B; Lappalainen, R E; Caco, C C; Winthrop, A L; Hollenberg, R D; Paes, B A

    1992-10-01

    Embryologically, cloacal exstrophy is thought to result from persistence and subsequent rupture of the infraumbilical cloacal membrane during the fifth embryonic week. We report a case of cloacal exstrophy in which a prenatal diagnosis was made prior to rupture of the cloacal membrane. A routine ultrasound at 17 weeks' gestation demonstrated monoamniotic twins. One twin was normal, but the other was found to have a sacral myelomeningocele, "rocker-bottom" feet, splaying of the pubic rami, and a large cystic mass protruding from the infraumbilical anterior abdominal wall. A repeat ultrasound was performed at 22 weeks, with the same findings. At 26 weeks, further examination showed disappearance of the abdominal cyst, a small omphalocele, no demonstrable bladder, and the suggestion of prolapsed bowel inferior to the umbilical cord insertion. After delivery at 34 weeks, the abnormal twin was found to have the typical findings of cloacal exstrophy, myelomeningocele, bilateral lower limb anomalies, and extremely foreshortened small bowel. Rupture of the presumed cloacal membrane after 22 weeks in this case is inconsistent with our current understanding of the embryology of this anomaly, and should stimulate a reexamination of the current concepts. If the characteristic features are recognized, cloacal exstrophy can be diagnosed by prenatal ultrasound, permitting prenatal counseling and appropriate perinatal management. PMID:1403521

  4. Rupture Risk Prediction of Abdominal Aortic Aneurysms (AAAs)

    NASA Astrophysics Data System (ADS)

    Tang, Rubing; Geindreau, Christian; Lasheras, Juan

    2007-11-01

    Currently there is no reliable method to predict the risk of rupture of AAAs. Our study seeks to improve the capabilities of biomedical techniques to better monitor the rupture risk of these aneurysms by quantifying the spatial and temporal distribution of mechanical stresses acting on the vessel walls. Specifically it aims at providing improved guidelines for surgical or endovascular intervention. Numerical simulations has been performed to calculate the wall stress distribution based on the peak blood pressure (static analysis) in both idealized and patient specific models of AAAs, using finite element method. Pulsatile blood flows were also simulated for idealized models with different parameters. Our results have shown that, in addition to the maximum AAA diameter, eccentricity and the presence of thrombus are also significant factors affecting the wall stress distribution, flow characteristics and hemodynamic forces in AAAs. Therefore, we confirmed that current criterion based solely on maximum diameter obtained from population-based statistics is not appropriate for the clinical management of AAA rupture, and other factors such as AAA shape and the presence of ILT should also be considered for a better assessment.

  5. Quantification of coronary arterial plaque volume using 3D reconstructions formed by fusing intravascular ultrasound and biplane angiography

    NASA Astrophysics Data System (ADS)

    Klingensmith, Jon D.; Vince, David G.; Shekhar, Raj; Kuban, Barry D.; Tuzcu, E. M.; Cornhill, J. Fredrick

    1999-05-01

    This paper, through plaque quantification, demonstrates the use of three-dimensional (3D) reconstructions of coronary arteries to assess compensatory enlargement. The lumen and medial-adventitial border are segmented from intravascular ultrasound (IVUS) images using a novel 3D method called active surfaces and the segmented data is used to calculate the cross-sectional area of the lumen and vessel, respectively. The area of plaque for each slice is the difference of the two. Information about the distance between path points, located using a calibrated biplane angiography system, is used for the calculation of plaque volume. This quantification system can be used to track the progression or regression of atherosclerosis and is currently being used to document compensatory enlargement, a physiological phenomenon in which the overall vessel cross-sectional area increases with an increase in plaque area with little or no decrease in luminal cross-sectional area. Four ex-vivo cases have been quantified, all demonstrating this remodeling mechanism, shown by strong positive correlation between plaque area and vessel area over the reconstructed length of the vessel (R equals 0.98, R equals 0.93, R equals 0.98, R equals 0.68).

  6. Association of Plaque Composition and Vessel Remodeling in Atherosclerotic Renal Artery Stenosis

    PubMed Central

    Kataoka, Tetsuro; Mathew, Verghese; Rubinshtein, Ronen; Rihal, Charanjit S.; Lennon, Ryan; Lerman, Lilach O.; Lerman, Amir

    2010-01-01

    OBJECTIVES The current study was designed to investigate the relationship between renal arterial structure and vessel remodeling in patients with atherosclerotic renal artery stenosis (RAS), compared with that seen in coronary artery disease (CAD). BACKGROUND The nature and the tissue characterization of atherosclerotic RAS lesions have not been fully explored. METHODS Gray scale and virtual histology (VH) intravascular ultrasound imaging was used to assess 23 lesions in 14 consecutive RAS patients and 20 left main trunk lesions in age-matched CAD patients. Analysis included assessment of vessel area and atherosclerotic plaque area of the main renal artery or left main trunk. Plaque was characterized as fibrous tissue, fibro-fatty tissue, necrotic core, and dense calcium. Remodeling was assessed by means of the remodeling index (RI). RESULTS Positive remodeling (defined as RI ?1.05) was present in 15 RAS and 9 CAD lesions, whereas intermediate/negative remodeling (RI <1.05) was present in 8 RAS and 11 CAD lesions. VH showed that the fibrous tissue was the most prominent plaque composition, followed by fibro-fatty, necrotic core, and dense calcium in both vascular beds. Greater vascular adaptive enlargement was observed in slices with plaque burden ?40% compared with plaque burden >40% (p < 0.001 for all). Vessel area had a positive association with the area of all VH components (p < 0.001, for all). VH analysis shows that the most powerful determinant of adaptive vessel enlargement is dense calcium in RAS (p < 0.001), while that is necrotic core in CAD (p < 0.001). Necrotic core and dense calcium areas were greater in lesions with positive remodeling compared with intermediate/negative remodeling (p = 0.03, p = 0.03, respectively, in RAS; p = 0.005, p = 0.03, respectively, in CAD). CONCLUSIONS The current study demonstrates in humans that plaque composition as assessed by VH intravascular ultrasound has an important role of adaptive vessel enlargement, and it is related to renal artery remodeling in RAS in a pattern similar to CAD. PMID:19356579

  7. Dynamic Interface Rupture in Extremely Heterogeneous Media

    NASA Astrophysics Data System (ADS)

    Uenishi, K.; Tsuji, K.

    2007-12-01

    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. u.ac.jp/~uenishi/

  8. Metrics for comparing dynamic earthquake rupture simulations

    USGS Publications Warehouse

    Barall, Michael; Harris, Ruth A.

    2014-01-01

    Earthquakes are complex events that involve a myriad of interactions among multiple geologic features and processes. One of the tools that is available to assist with their study is computer simulation, particularly dynamic rupture simulation. A dynamic rupture simulation is a numerical model of the physical processes that occur during an earthquake. Starting with the fault geometry, friction constitutive law, initial stress conditions, and assumptions about the condition and response of the near?fault rocks, a dynamic earthquake rupture simulation calculates the evolution of fault slip and stress over time as part of the elastodynamic numerical solution (? see the simulation description in the electronic supplement to this article). The complexity of the computations in a dynamic rupture simulation make it challenging to verify that the computer code is operating as intended, because there are no exact analytic solutions against which these codes’ results can be directly compared. One approach for checking if dynamic rupture computer codes are working satisfactorily is to compare each code’s results with the results of other dynamic rupture codes running the same earthquake simulation benchmark. To perform such a comparison consistently, it is necessary to have quantitative metrics. In this paper, we present a new method for quantitatively comparing the results of dynamic earthquake rupture computer simulation codes.

  9. Acrochordonous plaques in two Bulldogs and a Pug dog.

    PubMed

    Bidaut, A P; Gross, T L; Noli, C; Welle, M; Suter, M M

    2003-06-01

    Acrochordons or fibroepithelial polyps are exophytic to pedunculated tumour-like lesions of the skin reported to occur in humans and animals. We report here a new and unusual presentation of numerous, closely associated acrochordons forming a plaque, preferentially located at the dorsal neck of two Bulldogs and a Pug dog. Histopathologically these plaques were characterized by oedematous to fibrous cores enclosed by normal to moderately hyperplastic epidermis. We propose the name acrochordonous plaque to reflect the clinical lesion and the histopathological appearance of numerous, closely spaced acrochordons. Although the aetiology of these lesions remains unclear, there may be a breed predisposition for Bulldog-like breeds. PMID:12791052

  10. Age at intracranial aneurysm rupture among generations

    PubMed Central

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

    2009-01-01

    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

  11. Intraneuronal tau aggregation precedes diffuse plaque deposition, but amyloid-β changes occur before increases of tau in cerebrospinal fluid.

    PubMed

    Braak, Heiko; Zetterberg, Henrik; Del Tredici, Kelly; Blennow, Kaj

    2013-11-01

    In comparison to the levels in age and gender-matched controls, reduced levels of pathological amyloid-β protein in cerebrospinal fluid routinely precede the onset of Alzheimer's disease-related symptoms by several years, whereas elevated soluble abnormal tau fractions (phosphorylated tau, total tau protein) in cerebrospinal fluid are detectable only with the onset and progression of clinical symptoms. This sequence of events in cerebrospinal fluid (amyloid-β changes detectable prior to abnormal tau changes) contrasts with that in which both proteins develop in the brain, where intraneuronal tau inclusions (pretangles, neurofibrillary tangles, neuropil threads) appear decades before the deposition of amyloid-β plaques (diffuse plaques, neuritic plaques). This viewpoint attempts to address questions arising in connection with this apparent sequential discrepancy-questions and issues for which there are currently no clear-cut answers. PMID:23756600

  12. CT diagnosis of ruptured abdominal aortic aneurysm

    SciTech Connect

    Rosen, A.; Korobkin, M.; Silverman, P.M.; Moore, A.V. Jr.; Dunnick, N.R.

    1984-08-01

    Abdominal computed tomography was performed in six patients with suspected ruptured abdominal aortic aneurysm but in whom an alternate clinical diagnosis was seriously considered. In each patient, a large aortic aneurysm was demonstrated in association with a retroperitoneal accumulation of high-density blood. The retroperitoneal blood was primarily confined to the extracapsular perinephric space. In four of the six patients, a focal area of the aortic wall was indistinct on the side of the retroperitoneal hemorrhage at the presumed site of rupture. Five of the six patients underwent emergency surgery, which confirmed the site of aneurysm, presence of rupture and the location of fresh retroperitoneal blood.

  13. Gastric rupture after the Heimlich maneuver.

    PubMed

    Bintz, M; Cogbill, T H

    1996-01-01

    Since 1975, the Heimlich maneuver has been widely applied to relieve upper airway obstruction caused by aspirated material. Life-threatening complications have been documented following this simple procedure. We report two cases of gastric rupture after use of the Heimlich maneuver. Both patients experienced pulmonary and abdominal symptoms. The diagnosis was confirmed in each case by the demonstration of free intraperitoneal air on an upright chest roentgenogram. Full-thickness gastric rupture along the lesser curvature of the stomach was repaired in both patients; one patient died. Abdominal pain or persistent abdominal distention despite nasogastric suction after the Heimlich maneuver should prompt evaluation for possible gastric rupture. PMID:8576987

  14. Prolidase activity in chronic plaque psoriasis patients

    PubMed Central

    Aksoy, Nurten; Ozgöztas, Orhan; Sezen, Hatice; Yesilova, Yavuz; Turan, Enver

    2015-01-01

    Introduction Psoriasis is a chronic, inflammatory, T-cell-mediated and hyperproliferative skin disease characterized by erythematous, squamous, sharply circumscribed and infiltrated plaques. The metabolisms of the collagen proteins undergo considerable changes due to the acceleration of their turnovers as a result of increased prolidase activity in psoriasis patients. Aim To determine the level of prolidase activity in psoriasis patients and evaluate its relationship with the oxidative system. Material and methods The serum prolidase enzyme activity, total antioxidant levels and total oxidant levels of 40 psoriasis patients and a control group including 47 healthy individuals were analyzed by using their serum samples, and their oxidative stress indices were calculated. Results The prolidase levels (p < 0.01), total oxidant levels (p < 0.01) and oxidative stress index levels (p < 0.001) of the patient group were higher than the corresponding parameters in the control group. The total antioxidant level was low (p < 0.01). Although a positive correlation was found between the prolidase and total antioxidant levels and the total oxidant level, no correlation was found between prolidase and the oxidative stress index. Conclusions It has been determined that the activity of the prolidase enzyme increases due to the increased collage turnover in psoriasis patients. Increased serum oxidant levels and oxidative stress indices values may play a role in the pathogenesis of psoriasis. PMID:26015776

  15. Creep-rupture reliability analysis

    NASA Technical Reports Server (NTRS)

    Peralta-Duran, A.; Wirsching, P. H.

    1985-01-01

    A probabilistic approach to the correlation and extrapolation of creep-rupture data is presented. Time temperature parameters (TTP) are used to correlate the data, and an analytical expression for the master curve is developed. The expression provides a simple model for the statistical distribution of strength and fits neatly into a probabilistic design format. The analysis focuses on the Larson-Miller and on the Manson-Haferd parameters, but it can be applied to any of the TTP's. A method is developed for evaluating material dependent constants for TTP's. It is shown that optimized constants can provide a significant improvement in the correlation of the data, thereby reducing modelling error. Attempts were made to quantify the performance of the proposed method in predicting long term behavior. Uncertainty in predicting long term behavior from short term tests was derived for several sets of data. Examples are presented which illustrate the theory and demonstrate the application of state of the art reliability methods to the design of components under creep.

  16. Creep-rupture reliability analysis

    NASA Technical Reports Server (NTRS)

    Peralta-Duran, A.; Wirsching, P. H.

    1984-01-01

    A probabilistic approach to the correlation and extrapolation of creep-rupture data is presented. Time temperature parameters (TTP) are used to correlate the data, and an analytical expression for the master curve is developed. The expression provides a simple model for the statistical distribution of strength and fits neatly into a probabilistic design format. The analysis focuses on the Larson-Miller and on the Manson-Haferd parameters, but it can be applied to any of the TTP's. A method is developed for evaluating material dependent constants for TTP's. It is shown that optimized constants can provide a significant improvement in the correlation of the data, thereby reducing modelling error. Attempts were made to quantify the performance of the proposed method in predicting long term behavior. Uncertainty in predicting long term behavior from short term tests was derived for several sets of data. Examples are presented which illustrate the theory and demonstrate the application of state of the art reliability methods to the design of components under creep.

  17. 8. DETAIL OF EAST FRONT, SHOWING COMPANY NAME PLAQUE AND ...

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

    8. DETAIL OF EAST FRONT, SHOWING COMPANY NAME PLAQUE AND PARAPET. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Carr, Ryder & Adams Company, Powerhouse, Tenth & Jackson Streets, Dubuque, Dubuque County, IA

  18. 6. WEST FRONT DETAIL, SHOWING COMPANY NAME PLAQUE AND UPPER ...

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

    6. WEST FRONT DETAIL, SHOWING COMPANY NAME PLAQUE AND UPPER FLOOR FENESTRATION. VIEW TO EAST. - Commercial & Industrial Buildings, Becker-Hazelton Company Warehouse, 280 Iowa Street, Dubuque, Dubuque County, IA

  19. Aggregative Behavior of Bacteria Isolated from Canine Dental Plaque

    PubMed Central

    Elliott, David R.; Wilson, Michael; Buckley, Catherine M. F.; Spratt, David A.

    2006-01-01

    Interbacterial adhesion of bacteria isolated from canine dental plaque was assessed by performing a visual coaggregation assay. Using conditions mimicking those likely to be encountered in vivo, the entire cultivable plaque microbiota from a single dog was assessed, and eight (6.7%) unique coaggregation interactions were detected for 120 crosses. Transmission electron microscopy was used to visualize several of the bacteria in isolation and as coaggregates, which revealed surface structures that may be involved in adhesion and coaggregation. The results of this study indicate that the prevalence of coaggregating pairs of dental plaque bacteria in dogs is similar to the prevalence of coaggregating pairs of dental plaque bacteria reported in humans. In addition, genera found in both hosts generally exhibited similar coaggregation reactions; however, autoaggregation was found to be more common among oral bacteria isolated from dogs. PMID:16885267

  20. Elevation view of dedication plaque on east wall of south ...

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

    Elevation view of dedication plaque on east wall of south lobby - National Home for Disabled Volunteer Soldiers, Pacific Branch, Main Mental Health Building, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA

  1. Clathrin and Cx43 gap junction plaque endoexocytosis

    SciTech Connect

    Nickel, Beth M.; DeFranco, B. Hewa; Gay, Vernon L.; Murray, Sandra A.

    2008-10-03

    In earlier transmission electron microscopic studies, we have described pentilaminar gap junctional membrane invaginations and annular gap junction vesicles coated with short, electron-dense bristles. The similarity between these electron-dense bristles and the material surrounding clathrin-coated pits led us to suggest that the dense bristles associated with gap junction structures might be clathrin. To confirm that clathrin is indeed associated with annular gap junction vesicles and gap junction plaques, quantum dot immuno-electron microscopic techniques were used. We report here that clathrin associates with both connexin 43 (Cx43) gap junction plaques and pentilaminar gap junction vesicles. An important finding was the preferential localization of clathrin to the cytoplasmic surface of the annular or of the gap junction plaque membrane of one of the two contacting cells. This is consistent with the possibility that the direction of gap junction plaque internalization into one of two contacting cells is regulated by clathrin.

  2. 6. VIEW OF COMMEMORATIVE PLAQUE, EAST APPROACH GUARDRAIL, WHICH STATES ...

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

    6. VIEW OF COMMEMORATIVE PLAQUE, EAST APPROACH GUARDRAIL, WHICH STATES 'SALINE RIVER; ARK. GENERAL CONST. CO.; CONTRACTOR; ARKANSAS; STATE HIGHWAY DEPARTMENT; 1928, BRIDGE NO. __.' - Saline River Bridge, County Highway 365 across Saline River, Benton, Saline County, AR

  3. 33. HISTORIC PLAQUE MARKING WHERE JOHNSTON DIED, ADJACENT TO PATHWAY ...

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

    33. HISTORIC PLAQUE MARKING WHERE JOHNSTON DIED, ADJACENT TO PATHWAY WITH CONCRETE CULVERT LEADING NORTH OUT OF RAVINE TOWARD JOHNSTON MEMORIAL SITE. VIEW NW. - Shiloh National Military Park Tour Roads, Shiloh, Hardin County, TN

  4. 5. DETAIL VIEW, LOOKING WEST, SHOWING STONE PLAQUE INSCRIBED 'USRA, ...

    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

  5. A helical microwave antenna for welding plaque during balloon angioplasty

    SciTech Connect

    Liu, P.; Rappaport, C.M.

    1996-10-01

    A catheter-based microwave helix antenna has been developed in an attempt to improve the long-term success of balloon angioplasty treatment of arteriosclerosis. When the balloon is inflated to widen vessels obstructed with plaque, microwave power is deposited in the plaque, heating it, and thereby fixing it in place. By optimizing the helix pitch angle and excitation frequency, the antenna radiation pattern can be adjusted to deposit microwave power preferentially in the plaque while avoiding overheating the healthy artery. The optimal power deposition patterns of helical antennas are analytically computed for four-layered concentric and four-layered nonconcentric cylindrical geometries, which model symmetric and asymmetric occluded arteries. Experiments were performed on occluded artery phantom models with a prototype antenna for both symmetric and asymmetric models, which matched the theoretical predictions well, indicating almost complete power absorption in the low-water-content simulated plaque.

  6. HISTORIC IMAGE: VIEW OF MEIGS LODGE, WITH PLAQUE IN FOREGROUND. ...

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

    HISTORIC IMAGE: VIEW OF MEIGS LODGE, WITH PLAQUE IN FOREGROUND. PHOTOGRAPH CA. 1930S. CEMETERY MAINTENANCE LEDGER, NCA HISTORY COLLECTION. - Alexandria National Cemetery, 1450 Wilkes Street, Alexandria, Independent City, VA

  7. 32. STUDIO VIEW OF PLAQUE PLACED ON MILL HOUSE AT ...

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

    32. STUDIO VIEW OF PLAQUE PLACED ON MILL HOUSE AT TIME OF COMPLETION, COMMEMORATING EDWARD J. LUKE (SEE TEXT) - Sperry Corn Elevator Complex, Weber Avenue (North side), West of Edison Street, Stockton, San Joaquin County, CA

  8. PORT HUDSON NATIONAL CEMETERY PLAQUE, FORMERLY MOUNTED AT BASE OF ...

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

    PORT HUDSON NATIONAL CEMETERY PLAQUE, FORMERLY MOUNTED AT BASE OF FLAGPOLE, PRESENTLY STORED IN SERVICE BUILDING. VIEW TO WEST. - Port Hudson National Cemetery, 20978 Port Hickey Road, Zachary, East Baton Rouge Parish, LA

  9. Detail of aluminum plaque attached to the top of the ...

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

    Detail of aluminum plaque attached to the top of the northwest pilaster, facing west. - Oakland Avenue Viaduct, Oakland Avenue spanning U.S. Route 62 (State Route 2302) & Pine Run, Sharon, Mercer County, PA

  10. GETTYSBURG ADDRESS AND NATIONAL REGISTER PLAQUES, WITH HEADSTONES IN BACKGROUND. ...

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

    GETTYSBURG ADDRESS AND NATIONAL REGISTER PLAQUES, WITH HEADSTONES IN BACKGROUND. VIEW TO NORTHEAST. - Hot Springs National Cemetery, Virginia Medical Center 500 North Fifth Street, Hot Springs, Fall River County, SD

  11. 38. 100 foot through truss bridge original identification plaque ...

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

    38. 100 foot through truss - bridge original identification plaque located on the top of the north portal entrance. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  12. Dynamic Rupture Through Branched Fault Configurations With Off-fault Inelastic Response

    NASA Astrophysics Data System (ADS)

    Templeton, E. L.; Bhat, H. S.; Dmowska, R.; Rice, J. R.

    2008-12-01

    We analyze the propagation of shear ruptures along branched fault paths, allowing for elastic-plastic deformation in damaged fault-bordering zones. Geometric complexities (step-overs, bends and branches) along faults can control earthquake rupture propagation and in many cases confine propagation extent. Multiple numerical investigations have focused on such complexities during rupture (Harris and Day, 1991, 1993; Aochi et al., 2000; Kame et al., 2003) and, separately, on the role of inelastic off- fault material response during rupture (Andrews, 2005, 2007; Shi and Ben-Zion, 2006; Templeton and Rice, 2008; Viesca et al., 2008; Duan, 2008). Those inelastic studies use pressure-dependent elastic-plastic material descriptions such as Mohr-Coulomb or Drucker-Prager, which are standard models for describing plastic deformation in granulated or cracked materials like expected in damaged fault-bordering zones. We first summarize current understanding of rupture path selection at fault branching junctions, as supported by field and laboratory comparisons with modeling, including previous studies in our group based on boundary integral equation implementations of slip-weakening rupture, but with assumption of elastic off-fault response (Poliakov et al., 2002; Kame et al., 2003; Bhat et al., 2004, 2007; Fliss et al., 2005). We then show through dynamic finite element modeling how inelastic deformation in damaged fault-bordering zones contributes to path selection, and how branch activation affects seismic radiation. We assess dynamic path selection for a variety of branch angles and pre-stress directions, considering both sub-Rayleigh and supershear propagation speeds at the branching junction, and compare results for incohesive elastic-plastic off-fault response with those for elastic response. In particular, we have modeled rupture through possible fault branches along Solitario Canyon Fault (SCF) in the hanging wall, a normal fault bordering Yucca Mountain, NV. We find that (incohesive) inelastic response during rupture slightly increases the range of branch angles activated during dynamic rupture for supershear rupture speeds, but decreases the range of angles for sub-Rayleigh speeds. The inelastic response significantly reduces seismically generated ground accelerations at the proposed repository site, approximately 300 m below the crest of Yucca Mountain. We also address the energy partitioning during rupture, and find that branch activation can decrease the plastic energy dissipation during rupture compared with the no-branch case.

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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, Tdur. Tdur can be related to the critical parameters rupture length (L), depth (z), and shear modulus (?) while Tdur may be related to wide (W), slip (D), z or ?. 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/?, 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 Tdur is proportional L and greater Mo/?. Because Mo/? 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.

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

    SciTech Connect

    Madlazim

    2012-06-20

    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.

  15. Spontaneous rupture of ovarian cystadenocarcinoma: pre- and post-rupture computed tomography evaluation*

    PubMed Central

    Salvadori, Priscila Silveira; Bomfim, Lucas Novais; von Atzingen, Augusto Castelli; D’Ippolito, Giuseppe

    2015-01-01

    Epithelial ovarian tumors are the most common malignant ovarian neoplasms and, in most cases, eventual rupture of such tumors is associated with a surgical procedure. The authors report the case of a 54-year-old woman who presented with spontaneous rupture of ovarian cystadenocarcinoma documented by computed tomography, both before and after the event. In such cases, a post-rupture staging tends to be less favorable, compromising the prognosis. PMID:26543286

  16. Achilles tendon rupture in atypical patient populations.

    PubMed

    Kingsley, Peter

    2016-03-01

    Rupture of the Achilles tendon is a significant injury, and the likelihood of a good recovery is directly associated with early diagnosis and appropriate referral. Such injuries are commonly assessed and identified by practitioners working in 'minors' areas of emergency departments or urgent care settings. The literature frequently describes rupture of the Achilles tendon as 'typically sport-related' affecting 'middle-aged weekend warriors', but this aetiology accounts for only about 70% of such injuries. Factors such as the natural ageing process, obesity and use of some commonly prescribed medications, can increase the risk of developing a tendinopathy and subsequent rupture, often from a seemingly insignificant incident. However, research suggests that injuries in this patient population are more likely be missed on first examination. This article describes risk factors that should alert clinicians to the possibility of Achilles tendon rupture in 'atypical' patient populations. PMID:26948227

  17. Pregnancy-related rupture of arterial aneurysms.

    PubMed

    Barrett, J M; Van Hooydonk, J E; Boehm, F H

    1982-09-01

    Over 50 per cent of ruptured arterial aneurysms in women under the age of 40 are pregnancy-related. The hemodynamic and endocrine changes of pregnancy appear to be the cause of arterial alterations which may lead to new aneurysm formation and/or weakening of preexisting aneurysms. The most commonly reported arteries to have aneurysms rupture during pregnancy are the aorta, cerebral arteries, splenic artery, renal artery, coronary artery, and ovarian artery. In many instances, the rupture of an arterial aneurysm will initially simulate other less serious disease processes, thus delaying the correct diagnosis until a catastrophic event occurs. Early diagnosis and treatment of a ruptured arterial aneurysm are imperative in order to give optimal chances of survival to the mother and fetus. PMID:6752786

  18. Ruptured celiac artery aneurysm mimicking Boerhaave syndrome.

    PubMed

    Liu, Chien-Yu; Yang, Kai-Wei; Chen, Wei-Kung; Huang, Chen-Hsiung

    2013-09-01

    Ruptured celiac artery aneurysm is a rare cause for epigastric pain and is usually detected incidentally. Atypical presentation with postemetic epigastralgia and pleural effusion usually leads physicians to make the diagnosis of Boerhaave syndrome. Herein, we report a 32-year-old woman who was diagnosed with Boerhaave syndrome initially after presenting with acute postemetic epigastralgia and predominant left side pleural effusion. Diagnostic left thoracentesis yielded bloody fluid with similar amylase level to serum. The chest computed tomographic scan showed no evidence of esophageal rupture. However, a ruptured celiac artery aneurysm with retroperitoneal hematoma extending to the posterior mediastinum and bilateral pleural space was found incidentally. Although ruptured celiac artery aneurysm is an uncommon cause for postemetic epigastralgia, acute vascular events such as the previously stated cause should be the first impression rather than Boerhaave syndrome if the patient also presents with isolated pleural effusion containing unelevated amylase. PMID:23773770

  19. [Left Ventricular Rupture following Mitral Valve Replacement].

    PubMed

    Yamaguchi, Atsushi

    2015-07-01

    Left ventricular rupture is a rare but lethal complication after mitral valve replacement (MVR). Between 1989 and 2014, of 850 patients who underwent MVR, 6 developed left ventricular rupture in Saitama Medical Center, Jichi Medical University. Treasure type I rupture occurred in 5 patients and Miller type III in 1. Four cases developed ventricular rupture right after declamping of the ascending aorta, and the remaining 2 after the transfer to the intensive care unit( ICU). Prompt surgical therapy was achieved for the instant closure of the muscular wall defect under the cardiopulmonary bypass and cardiac arrest, however, leading to the disappointing result of 66.7% of hospital death. It is the most important to relieving the stress of the posterior wall of the left ventricle during mitral surgery by using the modification techniques with the preservation of posterior mitral leaflet and avoiding pre and afterload of the left ventricle right after the MVR. PMID:26197900

  20. Acute Iliac Artery Rupture: Endovascular Treatment

    SciTech Connect

    Chatziioannou, A.; Mourikis, D.; Katsimilis, J.; Skiadas, V. Koutoulidis, V.; Katsenis, K.; Vlahos, L.

    2007-04-15

    The authors present 7 patients who suffered iliac artery rupture over a 2 year period. In 5 patients, the rupture was iatrogenic: 4 cases were secondary to balloon angioplasty for iliac artery stenosis and 1 occurred during coronary angioplasty. In the last 2 patients, the rupture was secondary to iliac artery mycotic aneurysm. Direct placement of a stent-graft was performed in all cases, which was dilated until extravasation was controlled. Placement of the stent-graft was successful in all the cases, without any complications. The techniques used, results, and mid-term follow-up are presented. In conclusion, endovascular placement of a stent-graft is a quick, minimally invasive, efficient, and safe method for emergency treatment of acute iliac artery rupture, with satisfactory short- and mid-term results.

  1. Methotrexate toxicity presenting as cutaneous ulcerations on psoriatic plaques.

    PubMed

    Koçak, Asl?han Yonca; Koçak, O?uzhan; Aslan, Figen; Tekta?, Mustafa

    2013-10-01

    Methotrexate (MTX) is an effective but potentially toxic treatment for psoriasis. We describe a patient who administered 20?mg daily of MTX for 5?d and presented with ulcerated and necrotic lesions on the psoriatic plaques, mouth erosions and hair loss. However, his psoriatic plaques and ulcerations totally healed rapidly within two weeks and no recurrence has been observed for the 6 months of follow up. PMID:23537374

  2. Urease and Dental Plaque Microbial Profiles in Children

    PubMed Central

    Morou-Bermudez, Evangelia; Rodriguez, Selena; Bello, Angel S.; Dominguez-Bello, Maria G.

    2015-01-01

    Objective Urease enzymes produced by oral bacteria generate ammonia, which can have a significant impact on the oral ecology and, consequently, on oral health. To evaluate the relationship of urease with dental plaque microbial profiles in children as it relates to dental caries, and to identify the main contributors to this activity. Methods 82 supragingival plaque samples were collected from 44 children at baseline and one year later, as part of a longitudinal study on urease and caries in children. DNA was extracted; the V3–V5 region of the 16S rRNA gene was amplified and sequenced using 454 pyrosequencing. Urease activity was measured using a spectrophotometric assay. Data were analyzed with Qiime. Results Plaque urease activity was significantly associated with the composition of the microbial communities of the dental plaque (Baseline P = 0.027, One Year P = 0.012). The bacterial taxa whose proportion in dental plaque exhibited significant variation by plaque urease levels in both visits were the family Pasteurellaceae (Baseline P<0.001; One Year P = 0.0148), especially Haemophilus parainfluenzae. No association was observed between these bacteria and dental caries. Bacteria in the genus Leptotrichia were negatively associated with urease and positively associated with dental caries (Bonferroni P<0.001). Conclusions Alkali production by urease enzymes primarily from species in the family Pasteurellaceae can be an important ecological determinant in children’s dental plaque. Further studies are needed to establish the role of urease-associated bacteria in the acid/base homeostasis of the dental plaque, and in the development and prediction of dental caries in children. PMID:26418220

  3. Effect of rinse with calcium enriched milk on plaque fluid.

    PubMed

    Tanaka, M; Matsunaga, K; Kadoma, Y

    1999-09-01

    Previous research has shown that rinsing the mouth with milk significantly diminished the pH in dental plaque fluid; however, the degree of saturation with respect to the dental enamel (DS) was not significantly decreased because of an increase in the calcium ion concentration in plaque fluid. The aim of this study was to investigate the cariostatic effect of adding calcium to milk on the DS value of the plaque fluid after rinsing. Plaque samples were collected from 8 Japanese male dental students. Prior to plaque collection, all subjects refrained from practicing oral hygiene for 48 hr and fasted overnight. Supragingival plaque samples were collected from one side of the mouth of each subject, and then collected from the other side, following a 30-second rinse with 15 mL of calcium-enriched milk, which was prepared by adding calcium carbonate to ordinary milk, and a 10-minute waiting period. The samples were cleared by centrifugation, and the plaque fluid was analyzed for inorganic ions and pH, using an ion chromatograph and pH microelectrode, respectively. The calcium ion concentration of the milk was 6.4 mM, which was about 36% higher than that of ordinary milk. The pH decreased significantly (p<5%) from 6.4 to 6.1 following the rinse with calcium enriched milk, as tested by the paired t-test. The decrease in pH might have caused a reduction of the DS value; however, it was compensated for by a significant (p<0.5%) increase in the calcium ion concentration of plaque fluid. PMID:12160258

  4. Plaque retention on elastomeric ligatures. An in vivo study

    PubMed Central

    CONDÒ, R.; CASAGLIA, A.; CONDÒ, S.G.; CERRONI, L.

    2013-01-01

    SUMMARY Fixed orthodontic appliances make it difficult to maintain the oral hygiene, resulting in plaque accumulation. Retention of bacterial plaque, represents a risk for white spot lesions and development of periodontal disease. Aim Purpose of this study was to determine in vivo the retention of plaque on three different elastic ligatures, in comparison with stainless steel ligature, to determine a possible association between type of ligatures and accumulation of microorganisms. Material and Methods three elastic ligation systems were analyzed for plaque retention: ring-shape, clear, latex ligatures (Leone® Spa), ring-shape, grey, polyurethane ligatures (Micerium® Spa) and grey, polyurethane, Slide low-friction ligatures (Leone® Spa), compared with stainless steel ligatures (Leone® Spa) used as control. Forthy orthodontic patients undergoing fixed orthodontic therapy were selected. A sample for each type of ligature were applied inside the oral cavity of each subject. Samples were kept in the oral cavity for 28 days, ligating 0.16 X 0.22 stainless steel archwire to stainless steel orthodontic premolars brackets. The presence of bacterical slime was quantified by spectrophotometric method (crystal violet-Bouin’s fixative) and morphological observations was evaluated by Scanning Electron Microscopy (SEM). Results From analysis of bacterical slime emerges that all the elastics showed a low plaque retention, especially if compared to the group of steinless steel ligatures, that presented a greater plaque adhesion, statistically significant compared to the Slide group (r<0.0002) and the two elastic groups (r<0.0001). This study reported no significant difference between the Slide ligatures and the traditional elastic ligatures as regards the retention of plaque. SEM images showed presence of cocci, rods and few filamentous organisms and an interbacterial matrix in all observed samples. Conclusion Elastomeric ligatures showed a significant lower susceptibility to plaque adhesion, in comparison to the stainless steel of the metallic ligatures. No statistically significant difference was observed among the elastic devices. PMID:23741603

  5. 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

  6. Adiponectin-coated nanoparticles for enhanced imaging of atherosclerotic plaques

    PubMed Central

    Almer, Gunter; Wernig, Karin; Saba-Lepek, Matthias; Haj-Yahya, Samih; Rattenberger, Johannes; Wagner, Julian; Gradauer, Kerstin; Frascione, Daniela; Pabst, Georg; Leitinger, Gerd; Mangge, Harald; Zimmer, Andreas; Prassl, Ruth

    2011-01-01

    Background: Atherosclerosis is a leading cause of mortality in the Western world, and plaque diagnosis is still a challenge in cardiovascular medicine. The main focus of this study was to make atherosclerotic plaques visible using targeted nanoparticles for improved imaging. Today various biomarkers are known to be involved in the pathophysiologic scenario of atherosclerotic plaques. One promising new candidate is the globular domain of the adipocytokine adiponectin (gAd), which was used as a targeting sequence in this study. Methods: gAd was coupled to two different types of nanoparticles, namely protamine-oligonucleotide nanoparticles, known as proticles, and sterically stabilized liposomes. Both gAd-targeted nanoparticles were investigated for their potency to characterize critical scenarios within early and advanced atherosclerotic plaque lesions using an atherosclerotic mouse model. Aortic tissue from wild type and apolipoprotein E-deficient mice, both fed a high-fat diet, were stained with either fluorescent-labeled gAd or gAd-coupled nanoparticles. Ex vivo imaging was performed using confocal laser scanning microscopy. Results: gAd-targeted sterically stabilized liposomes generated a strong signal by accumulating at the surface of atherosclerotic plaques, while gAd-targeted proticles became internalized and showed more spotted plaque staining. Conclusion: Our results offer a promising perspective for enhanced in vivo imaging using gAd-targeted nanoparticles. By means of nanoparticles, a higher payload of signal emitting molecules could be transported to atherosclerotic plaques. Additionally, the opportunity is opened up to visualize different regions in the plaque scenario, depending on the nature of the nanoparticle used. PMID:21753879

  7. A Fault Evolution Model Including the Rupture Dynamic Simulation

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Chen, X.

    2011-12-01

    We perform a preliminary numerical simulation of seismicity and stress evolution along a strike-slip fault in a 3D elastic half space. Following work of Ben-Zion (1996), the fault geometry is devised as a vertical plane which is about 70 km long and 17 km wide, comparable to the size of San Andreas Fault around Parkfield. The loading mechanism is described by "backslip" method. The fault failure is governed by a static/kinetic friction law, and induced stress transfer is calculated with Okada's static solution. In order to track the rupture propagation in detail, we allow induced stress to propagate through the medium at the shear wave velocity by introducing a distance-dependent time delay to responses to stress changes. Current simulation indicates small to moderate earthquakes following the Gutenberg-Richter law and quasi-periodical characteristic large earthquakes, which are consistent with previous work by others. Next we will consider introducing a more realistic friction law, namely, the laboratory-derived rate- and state- dependent law, which can simulate more realistic and complicated sliding behavior such as the stable and unstable slip, the aseismic sliding and the slip nucleation process. In addition, the long duration of aftershocks is expected to be reproduced due to this time-dependent friction law, which is not available in current seismicity simulation. The other difference from previous work is that we are trying to include the dynamic ruptures in this study. Most previous study on seismicity simulation is based on the static solution when dealing with failure induced stress changes. However, studies of numerical simulation of rupture dynamics have revealed lots of important details which are missing in the quasi-static/quasi- dynamic simulation. For example, dynamic simulations indicate that the slip on the ground surface becomes larger if the dynamic rupture process reaches the free surface. The concentration of stress on the propagating crack tip keeps the rupture continuing easily. Therefore, comparing with the current simulation, we expect a different stress evolution after a large earthquake in a short time scale, which is very essential for the short-term prediction. Once the model is successfully constructed, we intend to apply it to the San Andreas Fault at Parkfield segment. We try to simulate the seismicity evolution and the distribution of coseismic and postseismic slip and interseismic creep in the past decades. We expect to reproduce some specific events and slip distributions.

  8. Dynamic rupture activation of backthrust fault branching

    NASA Astrophysics Data System (ADS)

    Xu, Shiqing; Fukuyama, Eiichi; Ben-Zion, Yehuda; Ampuero, Jean-Paul

    2015-03-01

    We perform dynamic rupture simulations to investigate the possible reactivation of backthrust branches triggered by ruptures along a main thrust fault. Simulations with slip-weakening fault friction and uniform initial stress show that fast propagation speed or long propagation distance of the main rupture promotes reactivation of backthrust over a range of branch angles. The latter condition may occur separately from the former if rupture speed is limited by an increasing slip-weakening distance towards the junction direction. The results suggest a trade-off between the amplitude and duration of the dynamic stress near the main rupture front for backthrust reactivation. Termination of the main rupture by a barrier can provide enhanced loading amplitude and duration along a backthrust rooted near the barrier, facilitating its reactivation especially with a high frictional resistance. The free surface and depth-dependent initial stress can have several additional effects. The sign of the triggered motion along the backthrust can be reversed from thrust to normal if a deeply nucleated main rupture breaks the free surface, while it is preserved as thrust if the main rupture is terminated by a barrier at depth. The numerical results are discussed in relation to several recent megathrust earthquakes in Sumatra, Chile, and Japan, and related topics such as branch feedbacks to the main fault. The dynamic view on backthrust fault branching provided by the study fills a gap not covered by quasi-static models or observations. A specific examined case of antithetic fault branching may be useful for indicating a barrier-like behavior along the main fault.

  9. Biomechanical rupture risk assessment of abdominal aortic aneurysms based on a novel probabilistic rupture risk index.

    PubMed

    Polzer, Stanislav; Gasser, T Christian

    2015-12-01

    A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach. PMID:26631334

  10. Preliminary study of the detectability of coronary plaque with PET

    NASA Astrophysics Data System (ADS)

    Delso, G.; Martinez-Möller, A.; Bundschuh, R. A.; Nekolla, S. G.; Ziegler, S. I.; Schwaiger, M.

    2011-04-01

    The evaluation of coronary plaque vulnerability could be of great diagnostic value in cardiology. Positron emission tomography (PET) is a good candidate due to its ability to quantify micromolar concentrations of targeted drugs. However, the detectability of sub-voxel targets such as coronary plaque is limited by partial volume effects and by cardiorespiratory motion. The goal of this paper is to investigate the impact of these factors in the detectability of plaque uptake. Radioactive markers were implanted on the epicardium of a pig and in vivo scans were performed. This was complemented with phantom measurements to determine the minimum detectable uptake as a function of background activity. Simulations were used to evaluate the effect of cardiorespiratory motion on the reconstructed lesions. Despite cardiorespiratory motion of up to 7 mm, the markers were detectable in the in vivo scans even after the injection of background. A lower limit of 250 Bq was found for a target to be detectable. Motion reduced the contrast of the reconstructed lesions to 23% of their static counterpart. Respiratory gating improved this to 49% of the static value. The results suggest that coronary plaque evaluation with PET is possible, provided that sufficient plaque-to-myocardium uptake contrast (50 to 100) can be achieved. This requirement increases exponentially for lesions with uptake below 250 Bq. The described experiments provide a means of estimating the minimum uptake and contrast required to ensure the detectability of plaque lesions.

  11. Isolation of Helicobacter pylori from dental plaque: A microbiological study

    PubMed Central

    Sudhakar, Uma; Anusuya, C. N.; Ramakrishnan, T.; Vijayalakshmi, R.

    2008-01-01

    Aim The aim of our study was to isolate H. pylori from dental plaque in gastric and duodenal ulcer patients and compare it with dental plaque of healthy subjects. Materials and Methods Fifty patients in the age range of 25-50 years who were endoscopically proven cases of duodenal and gastric ulcer were chosen. H. pylorus was isolated from the dental plaque of these patients using culture method and rapid urease test (RUT). It was compared with the dental plaque from control group (25 students). The specificity and sensitivity of RUT was compared with culture method. The oral hygiene index (OHI) score and plaque index were assessed. Results Ten percent positivity was observed in the study group by culture. Though RUT showed 70% positive isolation it is neither a specific test nor a conclusive test as compared to culture. The result correlates with oral hygiene in study population. Conclusion Further, more studies are needed to compare RUT and culture, with serology and polymerase chain reactions. The ability to detect H. pylori from dental plaque using these methods offer the potential for the noninvasive test for infection and would aid in support of oral transmission of H. pylori. PMID:20142948

  12. Visfatin Destabilizes Atherosclerotic Plaques in Apolipoprotein E–Deficient Mice

    PubMed Central

    Meng, Bin; Wang, Jitao; Qi, Tianjun; Zhang, Hui; Li, Tao; Zhao, Peiqing; Sun, Hui; Xu, Jia; Song, Haibo; Dong, Zhe; An, Fengshuang

    2016-01-01

    Objectives Although there is evidence that visfatin is associated with atherogenesis, the effect of visfatin on plaque stability has not yet been explored. Methods In vivo, vulnerable plaques were established by carotid collar placement in apolipoprotein E–deficient (ApoE−/−) mice, and lentivirus expressing visfatin (lenti-visfatin) was locally infused in the carotid artery. The lipid, macrophage, smooth muscle cell (SMC) and collagen levels were evaluated, and the vulnerability index was calculated. In vitro, RAW264.7 cells were stimulated with visfatin, and the MMPs expressions were assessed by western blot and immunofluorescence. And the mechanism that involved in visfatin-induced MMP-8 production was investigated. Results Transfection with lenti-visfatin significantly promoted the expression of visfatin which mainly expressed in macrophages in the plaque. Lenti-visfatin transfection significantly promoted the accumulation of lipids and macrophages, modulated the phenotypes of smooth muscle cells and decreased the collagen levels in the plaques, which significantly decreased the plaque stability. Simultaneously, transfection with lenti-visfatin significantly up-regulated the expression of MMP-8 in vivo, as well as MMP-1, MMP-2 and MMP-9. Recombinant visfatin dose- and time-dependently up-regulated the in vitro expression of MMP-8 in macrophages. Visfatin promoted the translocation of NF-κB, and inhibition of NF-κB significantly reduced visfatin-induced MMP-8 production. Conclusions Visfatin increased MMP-8 expression, promoted collagen degradation and increased the plaques vulnerability index. PMID:26848572

  13. Dosimetry for 125I seed (model 6711) in eye plaques.

    PubMed

    Chiu-Tsao, S T; Anderson, L L; O'Brien, K; Stabile, L; Liu, J C

    1993-01-01

    The effect of eye plaque materials (gold backing and silastic seed-carrier insert) on the dose distribution around a single 125I seed has been measured, using cubic lithium fluoride thermoluminescent dosimeters (TLDs) 1 mm on an edge, in a solid water eye phantom embedded in a solid water head phantom. With an 125I seed (model 6711) positioned in the center slot of the silastic insert for a 20-mm plaque of the design used in the collaborative ocular melanoma study (COMS), dose was measured at 2-mm intervals along the plaque central axis (the seed's transverse axis) and at various off-axis points, both with and without the COMS gold backing placed over the insert. Monte Carlo calculations (MORSE code) were performed, as well, for these configurations and closely the same geometry but assuming a large natural water phantom. Additional Monte Carlo calculations treated the case, both for 20- and 12-mm gold plaques, where the silastic insert is replaced by natural water. Relative to previous measurements taken in homogeneous medium of the same material (without the eye plaque), the dose reduction found by both Monte Carlo and TLD methods was greater at points farther from the seed along the central axis and, for a given central-axis depth, at larger off-axis distances. Removal of the gold backing from the plaque did not make measurable difference in the dose reduction results (10% at 1 cm). PMID:8497229

  14. Describing Soils: Calibration Tool for Teaching Soil Rupture Resistance

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  15. Describing Soils: Calibration Tool for Teaching Soil Rupture Resistance

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  16. Yield Stress Effects on Mucus Plug Rupture

    NASA Astrophysics Data System (ADS)

    Hu, Yingying; Bian, Shiyao; Grotberg, John C.; Takayama, Shuichi; Grotberg, James B.

    2012-11-01

    Mucus plugs can obstruct airways, resulting in lost gas exchange and inflammation. Yield stress, one of the significant rheological properties of mucus, plays a significant role in plug rupture. We use carbopol 940 gels as mucus simulants to study dynamics of mucus plug rupture in experiments. Yield stress increases with gel concentration increasing (0.1% ~0.3%). The yield stress of the 0.2% gel is about 530 dyn/cm2, which can simulate normal mucus. A 2D PDMS channel is used to simulate a collapsed airway of the 12th generation in a human lung. Plug rupture is driven by a pressure drop of 1.6 ×104 ~ 2.0 ×104 dyn/cm2. Initial plug length varies from half to two times the half channel width. A micro-PIV technique is used to acquire velocity fields during rupture, from which wall shear stress is derived. Plug shortening velocity increases with the pressure drop, but decreases with yield stress or the initial plug length. Wall shear stress increases with yield stress, which indicates more potential damage may occur to epithelial cells when pathologic mucus has a high yield stress. Near the rupture moment, a wall shear stress peak appears at the front of the film deposited by the plug during rupture. This work is supported by NIH: HL84370 and HL85156.

  17. The Rupture Behaviour Of Woven Fabrics Containing Kevlar Fibres

    NASA Astrophysics Data System (ADS)

    Mao, N.; Qu, J.; Darley, M.; Lingard, S.

    2012-07-01

    Woven fabrics containing high performance fibres are frequently used in spacecraft structures and the rupture behaviour of these fabrics heavily influences the performance of its final products. However, the initiation and propagation of a ruptured fracture in the woven fabrics is not clear and the interpretation of the results from different tear testing methods varies. Currently there is a lack of knowledge about both the characteristics of tear propagation woven fabrics containing high performance fibres such as Kevlar and the influence of the fabric structural parameters on the rupture behaviour of the fabrics; this knowledge gap creates difficulties for the engineering design and selection of suitable fabric materials to meet specific requirements in each application case involving such woven fabrics. In this paper, the tear propagations in a polyurethane-coated woven fabric containing Kevlar fibres based on two different tear testing standards are examined; the mechanism of tear propagation in woven fabrics and the influences of tear testing design on the interpretation of the results from different tear testing methods are discussed. It is expected that the results will guide both the engineering design of Kevlar woven fabric structures and the evaluation of the fabric performance.

  18. THE TRANSCRIPTIONAL SIGNATURES OF CELLS FROM THE HUMAN PEYRONIE'S DISEASE PLAQUE AND THE ABILITY OF THESE CELLS TO GENERATE A PLAQUE IN A RAT MODEL SUGGEST POTENTIAL THERAPEUTIC TARGETS

    PubMed Central

    Gelfand, R; Vernet, D; Kovanecz, I; Rajfer, J; Gonzalez-Cadavid, NF

    2015-01-01

    Introduction The success of medical therapies for Peyronie's disease (PD) has not been optimal, possibly because many of them went directly to clinical application without sufficient preclinical scientific research. Previous studies revealed cellular and molecular pathways involved in the formation of the PD plaque, and in particular the role of the myofibroblast. Aims The current work aimed to determine under normal and fibrotic conditions what differentiates PD cells from tunica albuginea (TA) and corpora cavernosa (CC) cells, by defining their global transcriptional signatures and testing in vivo whether PD cells can generate a PD like plaque Main Outcomes Measures Fibroproliferative features of PD cells and identification of related key genes as novel targets to reduce plaque size Methods Human TA, PD, and CC cells were grown with TGF?1 (TA+, PD+, CC+) or without it (TA?, PD?, CC?) and assayed by: a) immunofluorescence, western blot and RT/PCR for myofibroblast, smooth muscle cell and stem cell markers; b) collagen content; and c) DNA microarray analysis. The ability of PD+ cells to induce a PD like plaque in an immuno-suppressed rat model was assessed by Masson trichrome and Picrosirius Red. Results Upon TGF?1stimulation, collagen levels were increased by myofibroblasts in the PD+ but not in the CC+ cells. The transcriptional signature of the PD? cells identified fibroproliferative, myogenic (myofibroblasts), inflammatory, and collagen turnover genes, that differentiate them from TA? or CC? cells, and respond to TGF?1 with a PD+ fibrotic phenotype, by upregulation of IGF1, ACTG2, MYF5, ACTC1, PSTN, COL III, MMP3, and others. The PD+ cells injected into the TA of the rat induce a PD like plaque. Conclusions This suggests a novel combination therapy to eliminate a PD plaque, by targeting the identified genes to: a) improve collagenase action by stimulating endogenous MMPs specific to key collagen types, and b) counteract fibromatosis by inhibiting myofibroblast generation, proliferation and/or apoptosis. PMID:25496134

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

    SciTech Connect

    Gagne, Nolan L.; Leonard, Kara L.; Rivard, Mark J.

    2012-06-15

    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.

  20. Management of hepatocellular carcinoma rupture in the caudate lobe

    PubMed Central

    Hong, De-Fei; Liu, Ying-Bin; Peng, Shu-You; Pang, Jin-Zhong; Wang, Zhi-Fei; Cheng, Jian; Shen, Guo-Liang; Zhang, Yuan-Biao

    2015-01-01

    AIM: To demonstrate that caudate lobectomy is a valid treatment in cases of hepatocellular carcinoma (HCC) rupture in the caudate lobe based on our experience with the largest case series reported to date. METHODS: A retrospective study of eight patients presenting with spontaneous rupture and hemorrhage of HCC in the caudate lobe was conducted. Two patients underwent ineffective transarterial embolization preoperatively. Caudate lobectomy was performed in all eight patients. Bilateral approach was taken in seven cases for isolated complete caudate lobectomy. Left-sided approach was employed in one case for isolated partial caudate lobectomy. Transarterial chemoembolization was performed postoperatively in all patients. RESULTS: Caudate lobectomy was successfully completed in all eight cases. The median time delay from the diagnosis to operation was 5 d (range: 0.25-9). Median operating time was 200 min (range: 120-310) with a median blood loss of 900 mL (range: 300-1500). Five patient remained in long-term follow-up, with one patient becoming lost to follow-up at 3 years and two patients currently alive at 7 and 19 mo. One patient required reoperation due to recurrence. Gamma knife intervention was performed for brain metastasis in another case. Two patients survived for 10 and 84 mo postoperatively, ultimately succumbing to multiple organ metastases. CONCLUSION: Caudate lobectomy is the salvage choice for HCC rupture in the caudate lobe. Local anatomy and physiologic features of the disease render caudate lobectomy a technically difficult operation. Postponement of surgical intervention is thus recommended while the rupture remains hemodynamically stable until an experienced surgeon becomes available. Prognosis is confounded by numerous factors, but long-term survival can be expected in the majority of cases. PMID:26185390

  1. Altered microglial response to A? plaques in APPPS1-21 mice heterozygous for TREM2

    PubMed Central

    2014-01-01

    Background Recent genome-wide association studies linked variants in TREM2 to a strong increase in the odds of developing Alzheimer’s disease. The mechanism by which TREM2 influences the susceptibility to Alzheimer’s disease is currently unknown. TREM2 is expressed by microglia and is thought to regulate phagocytic and inflammatory microglial responses to brain pathology. Given that a single allele of variant TREM2, likely resulting in a loss of function, conferred an increased risk of developing Alzheimer’s disease, we tested whether loss of one functional trem2 allele would affect A? plaque deposition or the microglial response to A? pathology in APPPS1-21 mice. Results There was no significant difference in A? deposition in 3-month old or 7-month old APPPS1-21 mice expressing one or two copies of trem2. However, 3-month old mice with one copy of trem2 exhibited a marked decrease in the number and size of plaque-associated microglia. While there were no statistically significant differences in cytokine levels or markers of microglial activation in 3- or 7-month old animals, there were trends towards decreased expression of NOS2, C1qa, and IL1a in 3-month old TREM2+/? vs. TREM2+/+ mice. Conclusions Loss of a single copy of trem2 had no effect on A? pathology, but altered the morphological phenotype of plaque-associated microglia. These data suggest that TREM2 is important for the microglial response to A? deposition but that a 50% decrease inTREM2 expression does not affect A? plaque burden. PMID:24893973

  2. Insulin inhibits inflammation and promotes atherosclerotic plaque stability via PI3K-Akt pathway activation.

    PubMed

    Yan, Hao; Ma, Ying; Li, Yan; Zheng, Xiaohui; Lv, Ping; Zhang, Yuan; Li, Jia; Ma, Meijuan; Zhang, Le; Li, Congye; Zhang, Rongqing; Gao, Feng; Wang, Haichang; Tao, Ling

    2016-02-01

    Toll-like receptor (TLR) 4 induced inflammation was reported to play an important role in atherosclerotic plaque stability. Recent studies indicated that insulin could inhibit inflammation by activating phosphatidylinositol 3-kinase-Akt-dependent (PI3K-Akt) signaling pathway. In the current study, we hypothesized that insulin would inhibit TLR4 induced inflammation via promoting PI3K-Akt activation, thus enhancing the stabilization of atherosclerotic plaques. In order to mimic the process of plaque formation, monocyte-macrophage lineage RAW264.7 were cultured and induced to form foam cells by oxidized LDL (ox-LDL). Oil red O staining results showed that insulin significantly restrained ox-LDL-induced foam cell formation. Analysis of inflammatory reaction during foam cell formation indicated that insulin significantly down-regulated the expression of tumor necrosis factor (TNF)-?, interleukin (IL)-6 levels, inhibited TLR4, myeloid differentiation primary response gene (MyD) 88 and nuclear factor (NF)-?B. Further mechanism analysis showed that pretreating with the PI3K blocker, wortmannin dramatically dampened the insulin-induced up-regulation of pAkt expression. Additionally, blockade of PI3K-Akt signaling also dampened the immunosuppression effect brought by insulin. Following the construction of a rodent atherosclerosis model, pretreatment of insulin resulted in an evident decrease in lipid deposition of the blood vessel wall, serum levels of TNF-? and IL-6, and numbers of infiltrated macrophages and foam cells. Taken together, these results suggested that insulin might inhibit inflammation and promote atherosclerotic plaque stability via the PI3K-Akt pathway by targeting TLR4-MyD88-NF-?B signaling. Our findings may provide a potential target for the prevention of cardiovascular disease. PMID:26681144

  3. Spontaneous uterine rupture in the 35th week of gestation after laparoscopic adenomyomectomy

    PubMed Central

    Nagao, Yukari; Osato, Kazuhiro; Kubo, Michiko; Kawamura, Takuya; Ikeda, Tomoaki; Yamawaki, Takaharu

    2016-01-01

    Uterine rupture rarely occurs during pregnancy, but it is a critical situation if so. It is already known that a history of uterine surgeries, such as cesarean section or myomectomy, is a risk factor for uterine rupture. Currently, the laparoscopic adenomyomectomy is a widely performed procedure, but associated risks have not been defined. We observed a case of spontaneous uterine rupture in a patient during the 35th week of gestation, after a laparoscopic adenomyomectomy. A 42-year-old, gravida 2, para 0 woman became pregnant after a laparoscopic adenomyomectomy and her pregnancy was conventional. At a scheduled date in the 35th week of gestation, after combined spinal epidural anesthesia and frequent uterine contractions, a weak pain suddenly ensued. After 13 minutes of uterine contractions, vaginal bleeding was evident. A cesarean section was performed, and the uterine rupture was found in the scar. After a laparoscopic adenomyomectomy, a pregnant uterus can easily rupture by rather weak and short uterine contractions, and is characterized by vaginal bleeding. When uterine bleeding is observed in pregnant women that have a history of adenomyomectomy, one should consider uterine rupture. PMID:26719729

  4. Perioperative Variables Contributing to the Rupture of Intracranial Aneurysm: An Update

    PubMed Central

    Cappellani, Ronald B.; Sandu, Nora; Daya, Jayesh

    2013-01-01

    Background. Perioperative aneurysm rupture (PAR) is one of the most dreaded complications of intracranial aneurysms, and approximately 80% of nontraumatic SAHs are related to such PAR aneurysms. The literature is currently scant and even controversial regarding the issues of various contributory factors on different phases of perioperative period. Thus this paper highlights the current understanding of various risk factors, variables, and outcomes in relation to PAR and try to summarize the current knowledge. Method. We have performed a PubMed search (1 January 1991–31 December 2012) using search terms including “cerebral aneurysm,” “intracranial aneurysm,” and “intraoperative/perioperative rupture.” Results. Various risk factors are summarized in relation to different phases of perioperative period and their relationship with outcome is also highlighted. There exist many well-known preoperative variables which are responsible for the highest percentage of PAR. The role of other variables in the intraoperative/postoperative period is not well known; however, these factors may have important contributory roles in aneurysm rupture. Preoperative variables mainly include natural course (age, gender, and familial history) as well as the pathophysiological factors (size, type, location, comorbidities, and procedure). Previously ruptured aneurysm is associated with rupture in all the phases of perioperative period. On the other hand intraoperative/postoperative variables usually depend upon anesthesia and surgery related factors. Intraoperative rupture during predissection phase is associated with poor outcome while intraoperative rupture at any step during embolization procedure imposes poor outcome. Conclusion. We have tried to create such an initial categorization but know that we cannot scale according to its clinical importance. Thorough understanding of various risk factors and other variables associated with PAR will assist in better clinical management as well as patient care in this group and will give insight into the development and prevention of such a catastrophic complication in these patients. PMID:24324371

  5. Can anti-erosion dentifrices also provide effective plaque control?

    PubMed Central

    Bellamy, PG; Prendergast, M; Strand, R; Yu, Z; Day, TN; Barker, ML; Mussett, AJ

    2011-01-01

    Objective: While gingivitis and caries continue to be prevalent issues, there is growing concern about dental erosion induced by dietary acids. An oral hygiene product that protects against all these conditions would be beneficial. This study investigated the potential of two anti-erosion dentifrices to inhibit plaque. Methods: This was a randomized, three-period, two-treatment, double-blind, crossover study evaluating a stannous chloride/sodium fluoride dentifrice (SnCl2/NaF, blend-a-med® Pro Expert) and a popular anti-erosion dentifrice (NaF, Sensodyne® ProNamel™). During Period 3, subjects were randomized to repeat one treatment to evaluate any product carryover effects. Each treatment period was 17 days. Test dentifrices were used with a standard manual toothbrush. Digital plaque image analysis (DPIA) was employed at the end of each period to evaluate plaque levels (i) overnight (am prebrush); (ii) post-brushing with the test product (am post-brush); and (iii) mid-afternoon (pm). Analysis was conducted via an objective computer algorithm, which calculated total area of visible plaque. Results: Twenty-seven subjects completed the study. At all time points, subjects had statistically significantly (P ≤ 0.0001) lower plaque levels after using the SnCl2/NaF dentifrice than the NaF dentifrice. The antiplaque benefit for the SnCl2/NaF dentifrice versus the NaF dentifrice was: am prebrush = 26.0%; am post-brushing = 27.9%; pm = 25.7%. Conclusions: The SnCl2/NaF dentifrice provided significantly greater daytime and overnight plaque inhibition than the NaF toothpaste. When recommending dentifrice to patients susceptible to dental erosion, clinicians can consider one that also inhibits plaque. PMID:21356021

  6. Fluorescence immunoassay for detecting periodontal bacterial pathogens in plaque.

    PubMed Central

    Wolff, L F; Anderson, L; Sandberg, G P; Aeppli, D M; Shelburne, C E

    1991-01-01

    A particle concentration fluorescence immunoassay has been modified into a bacterial concentration fluorescence immunoassay (BCFIA) to rapidly detect periodontopathic bacteria in human plaque samples. The BCFIA utilizes fluorescently tagged monoclonal antibodies (MAbs) directed against the lipopolysaccharide of selected gram-negative plaque bacteria. Microorganisms closely associated with periodontal disease that can be identified in plaque with the BCFIA include Porphyromonas gingivalis, Bacteroides intermedius, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Eikenella corrodens. Briefly, the procedure involved mixing a patient's plaque sample or other bacterial preparation with a species-specific fluorescein isothiocyanate-labeled MAb in a specialized microtiter plate. This mixture was incubated to allow binding of the MAb to its homologous bacteria. The bound and unbound fluorescent tagged MAbs were separated by filtration in the modified microtiter plate, and the total bacterial bound fluorescence was determined with a fluorimeter. The number of a specific bacterial species in a given plaque sample or other bacterial suspension was estimated by reference to a primary standard carried through the BCFIA. The lower detection limit of the BCFIA was 10(3) to 10(4) bacterial cells from single cultures of bacteria or 10(4) bacterial cells in mixed cultures. The coefficient of variation within and between plates for each of the five bacterium-specific MAbs in screening plaque for the periodontal pathogens was less than 10%. These results demonstrate that microbes in plaque can be used as the solid phase in the BCFIA to detect and quantitate MAbs associated with specific bacteria quickly and reliably. PMID:1761686

  7. Acid production in dental plaque after exposure to probiotic bacteria

    PubMed Central

    2012-01-01

    Background The increasing interest in probiotic lactobacilli in health maintenance has raised the question of potential risks. One possible side effect could be an increased acidogenicity in dental plaque. The aim of this study was to investigate the effect of probiotic lactobacilli on plaque lactic acid (LA) production in vitro and in vivo. Methods In the first part (A), suspensions of two lactobacilli strains (L. reuteri DSM 17938, L. plantarum 299v) were added to suspensions of supragingival dental plaque collected from healthy young adults (n=25). LA production after fermentation with either xylitol or fructose was analyzed. In the second part (B), subjects (n=18) were given lozenges with probiotic lactobacilli (L. reuteri DSM 17938 and ATCC PTA 5289) or placebo for two weeks in a double-blinded, randomized cross-over trial. The concentration of LA in supragingival plaque samples was determined at baseline and after 2 weeks. Salivary counts of mutans streptococci (MS) and lactobacilli were estimated with chair-side methods. Results Plaque suspensions with L. reuteri DSM 17938 produced significantly less LA compared with L. plantarum 299v or controls (p<0.05). Fructose gave higher LA concentrations than xylitol. In part B, there were no significant differences in LA production between baseline and follow up in any of the groups and no differences between test and placebo were displayed. The salivary MS counts were not significantly altered during the intervention but the lactobacilli counts increased significantly in the test group (p<0.05). Conclusion Lactic acid production in suspensions of plaque and probiotic lactobacilli was strain-dependant and the present study provides no evidence of an increase in plaque acidity by the supply of selected probiotic lactobacilli when challenged by fructose or xylitol. The study protocol was approved by The Danish National Committee on Biomedical Research Ethics (protocol no H-2-2010-112). Trial registration NCT01700712 PMID:23092239

  8. Fast in vivo imaging of amyloid plaques using μ-MRI Gd-staining combined with ultrasound-induced blood-brain barrier opening.

    PubMed

    Santin, Mathieu D; Debeir, Thomas; Bridal, S Lori; Rooney, Thomas; Dhenain, Marc

    2013-10-01

    Amyloid plaques are one of the major microscopic lesions that characterize Alzheimer's disease. Current approaches to detect amyloid plaques by using magnetic resonance imaging (MRI) contrast agents require invasive procedures to penetrate the blood-brain barrier (BBB) and to deliver the contrast agent into the vicinity of amyloid plaques. Here we have developed a new protocol (US-Gd-staining) that enables the detection of amyloid plaques in the brain of an APP/PS1 transgenic mouse model of amyloidosis after intra-venous injection of a non-targeted, clinically approved MRI contrast agent (Gd-DOTA, Dotarem®) by transiently opening the BBB with unfocused ultrasound (1 MHz) and clinically approved microbubbles (Sonovue®, Bracco). This US-Gd-staining protocol can detect amyloid plaques with a short imaging time (32 min) and high in-plane resolution (29 μm). The sensitivity and resolution obtained is at least equal to that provided by MRI protocols using intra-cerebro-ventricular injection of contrast agents, a reference method used to penetrate the BBB. To our knowledge this is the first study to demonstrate the ability of MR imaging to detect amyloid plaques by using a peripheral intra-venous injection of a clinically approved NMR contrast agent. PMID:23660031

  9. A direct vulnerable atherosclerotic plaque elasticity reconstruction method based on an original material-finite element formulation: theoretical framework

    PubMed Central

    Bouvier, Adeline; Deleaval, Flavien; Doyley, Marvin M; Yazdani, Saami K; Finet, Gérard; Le Floc'h, Simon; Cloutier, Guy; Pettigrew, Roderic I; Ohayon, Jacques

    2016-01-01

    The peak cap stress (PCS) amplitude is recognized as a biomechanical predictor of vulnerable plaque (VP) rupture. However, quantifying PCS in vivo remains a challenge since the stress depends on the plaque mechanical properties. In response, an iterative material finite element (FE) elasticity reconstruction method using strain measurements has been implemented for the solution of these inverse problems. Although this approach could resolve the mechanical characterization of VPs, it suffers from major limitations since (i) it is not adapted to characterize VPs exhibiting high material discontinuities between inclusions, and (ii) does not permit real time elasticity reconstruction for clinical use. The present theoretical study was therefore designed to develop a direct material-FE algorithm for elasticity reconstruction problems which accounts for material heterogeneities. We originally modified and adapted the extended FE method (Xfem), used mainly in crack analysis, to model material heterogeneities. This new algorithm was successfully applied to six coronary lesions of patients imaged in vivo with intravascular ultrasound. The results demonstrated that the mean relative absolute errors of the reconstructed Young's moduli obtained for the arterial wall, fibrosis, necrotic core, and calcified regions of the VPs decreased from 95.3±15.56%, 98.85±72.42%, 103.29±111.86% and 95.3±10.49%, respectively, to values smaller than 2.6 × 10?8±5.7 × 10?8% (i.e. close to the exact solutions) when including modified-Xfem method into our direct elasticity reconstruction method. PMID:24240392

  10. Elevated Uptake of Plasma Macromolecules by Regions of Arterial Wall Predisposed to Plaque Instability in a Mouse Model

    PubMed Central

    Mohri, Zahra; Rowland, Ethan M.; Clarke, Lindsey A.; De Luca, Amalia; Peiffer, Véronique; Krams, Rob; Sherwin, Spencer J.; Weinberg, Peter D.

    2014-01-01

    Atherosclerosis may be triggered by an elevated net transport of lipid-carrying macromolecules from plasma into the arterial wall. We hypothesised that whether lesions are of the thin-cap fibroatheroma (TCFA) type or are less fatty and more fibrous depends on the degree of elevation of transport, with greater uptake leading to the former. We further hypothesised that the degree of elevation can depend on haemodynamic wall shear stress characteristics and nitric oxide synthesis. Placing a tapered cuff around the carotid artery of apolipoprotein E -/- mice modifies patterns of shear stress and eNOS expression, and triggers lesion development at the upstream and downstream cuff margins; upstream but not downstream lesions resemble the TCFA. We measured wall uptake of a macromolecular tracer in the carotid artery of C57bl/6 mice after cuff placement. Uptake was elevated in the regions that develop lesions in hyperlipidaemic mice and was significantly more elevated where plaques of the TCFA type develop. Computational simulations and effects of reversing the cuff orientation indicated a role for solid as well as fluid mechanical stresses. Inhibiting NO synthesis abolished the difference in uptake between the upstream and downstream sites. The data support the hypothesis that excessively elevated wall uptake of plasma macromolecules initiates the development of the TCFA, suggest that such uptake can result from solid and fluid mechanical stresses, and are consistent with a role for NO synthesis. Modification of wall transport properties might form the basis of novel methods for reducing plaque rupture. PMID:25531765

  11. A direct vulnerable atherosclerotic plaque elasticity reconstruction method based on an original material-finite element formulation: theoretical framework

    NASA Astrophysics Data System (ADS)

    Bouvier, Adeline; Deleaval, Flavien; Doyley, Marvin M.; Yazdani, Saami K.; Finet, Gérard; Le Floc'h, Simon; Cloutier, Guy; Pettigrew, Roderic I.; Ohayon, Jacques

    2013-12-01

    The peak cap stress (PCS) amplitude is recognized as a biomechanical predictor of vulnerable plaque (VP) rupture. However, quantifying PCS in vivo remains a challenge since the stress depends on the plaque mechanical properties. In response, an iterative material finite element (FE) elasticity reconstruction method using strain measurements has been implemented for the solution of these inverse problems. Although this approach could resolve the mechanical characterization of VPs, it suffers from major limitations since (i) it is not adapted to characterize VPs exhibiting high material discontinuities between inclusions, and (ii) does not permit real time elasticity reconstruction for clinical use. The present theoretical study was therefore designed to develop a direct material-FE algorithm for elasticity reconstruction problems which accounts for material heterogeneities. We originally modified and adapted the extended FE method (Xfem), used mainly in crack analysis, to model material heterogeneities. This new algorithm was successfully applied to six coronary lesions of patients imaged in vivo with intravascular ultrasound. The results demonstrated that the mean relative absolute errors of the reconstructed Young's moduli obtained for the arterial wall, fibrosis, necrotic core, and calcified regions of the VPs decreased from 95.3±15.56%, 98.85±72.42%, 103.29±111.86% and 95.3±10.49%, respectively, to values smaller than 2.6 × 10-8±5.7 × 10-8% (i.e. close to the exact solutions) when including modified-Xfem method into our direct elasticity reconstruction method.

  12. Ultraviolet Phototherapy Management of Moderate-to-Severe Plaque Psoriasis

    PubMed Central

    2009-01-01

    Executive Summary Objective The purpose of this evidence based analysis was to determine the effectiveness and safety of ultraviolet phototherapy for moderate-to-severe plaque psoriasis. Research Questions The specific research questions for the evidence review were as follows: What is the safety of ultraviolet phototherapy for moderate-to-severe plaque psoriasis? What is the effectiveness of ultraviolet phototherapy for moderate-to-severe plaque psoriasis? Clinical Need: Target Population and Condition Psoriasis is a common chronic, systemic inflammatory disease affecting the skin, nails and occasionally the joints and has a lifelong waning and waxing course. It has a worldwide occurrence with a prevalence of at least 2% of the general population, making it one of the most common systemic inflammatory diseases. The immune-mediated disease has several clinical presentations with the most common (85% - 90%) being plaque psoriasis. Characteristic features of psoriasis include scaling, redness, and elevation of the skin. Patients with psoriasis may also present with a range of disabling symptoms such as pruritus (itching), pain, bleeding, or burning associated with plaque lesions and up to 30% are classified as having moderate-to-severe disease. Further, some psoriasis patients can be complex medical cases in which diabetes, inflammatory bowel disease, and hypertension are more likely to be present than in control populations and 10% also suffer from arthritis (psoriatic arthritis). The etiology of psoriasis is unknown but is thought to result from complex interactions between the environment and predisposing genes. Management of psoriasis is related to the extent of the skin involvement, although its presence on the hands, feet, face or genitalia can present challenges. Moderate-to-severe psoriasis is managed by phototherapy and a range of systemic agents including traditional immunosuppressants such as methotrexate and cyclospsorin. Treatment with modern immunosuppressant agents known as biologicals, which more specifically target the immune defects of the disease, is usually reserved for patients with contraindications and those failing or unresponsive to treatments with traditional immunosuppressants or phototherapy. Treatment plans are based on a long-term approach to managing the disease, patient’s expectations, individual responses and risk of complications. The treatment goals are several fold but primarily to: 1) improve physical signs and secondary psychological effects, 2) reduce inflammation and control skin shedding, 3) control physical signs as long as possible, and to 4) avoid factors that can aggravate the condition. Approaches are generally individualized because of the variable presentation, quality of life implications, co-existent medical conditions, and triggering factors (e.g. stress, infections and medications). Individual responses and commitments to therapy also present possible limitations. Phototherapy Ultraviolet phototherapy units have been licensed since February 1993 as a class 2 device in Canada. Units are available as hand held devices, hand and foot devices, full-body panel, and booth styles for institutional and home use. Units are also available with a range of ultraviolet A, broad and narrow band ultraviolet B (BB-UVB and NB-UVB) lamps. After establishing appropriate ultraviolet doses, three-times weekly treatment schedules for 20 to 25 treatments are generally needed to control symptoms. Evidence-Based Analysis Methods The literature search strategy employed keywords and subject headings to capture the concepts of 1) phototherapy and 2) psoriasis. The search involved runs in the following databases: Ovid MEDLINE (1996 to March Week 3 2009), OVID MEDLINE In-Process and Other Non-Indexed Citations, EMBASE (1980 to 2009 Week 13), the Wiley Cochrane Library, and the Centre for Reviews and Dissemination/International Agency for Health Technology Assessment. Parallel search strategies were developed for the remaining databases. Search results were limited to human and English-language published between January 1999 and March 31, 2009. Search alerts were generated and reviewed for relevant literature up until May 31, 2009. Inclusion Criteria Exclusion Criteria English language reports and human studies Ultraviolet phototherapy interventions for plaque-type psoriasis Reports involving efficacy and/or safety outcome studies Original reports with defined study methodology Standardized measurements on outcome events such as technical success, safety, effectiveness, durability, quality of life or patient satisfaction Non-systematic reviews, letters, comments and editorials Randomized trials involving side-to-side or half body comparisons Randomized trials not involving ultraviolet phototherapy intervention for plaque-type psoriasis Trials involving dosing studies, pilot feasibility studies or lacking control groups Summary of Findings A 2000 health technology evidence report on the overall management of psoriasis by The National Institute Health Research (NIHR) Health Technology Assessment Program of the UK was identified in the MAS evidence-based review. The report included 109 RCT studies published between 1966 and June 1999 involving four major treatment approaches – 51 on phototherapy, 32 on oral retinoids, 18 on cyclosporin and five on fumarates.. The absence of RCTs on methotrexate was noted as original studies with this agent had been performed prior to 1966. Of the 51 RCT studies involving phototherapy, 22 involved UVA, 21 involved UVB, five involved both UVA and UVB and three involved natural light as a source of UV. The RCT studies included comparisons of treatment schedules, ultraviolet source, addition of adjuvant therapies, and comparisons between phototherapy and topical treatment schedules. Because of heterogeneity, no synthesis or meta-analysis could be performed. Overall, the reviewers concluded that the efficacy of only five therapies could be supported from the RCT-based evidence review: photochemotherapy or phototherapy, cyclosporin, systemic retinoids, combination topical vitamin D3 analogues (calcipotriol) and corticosteroids in combination with phototherapy and fumarates. Although there was no RCT evidence supporting methotrexate, it’s efficacy for psoriasis is well known and it continues to be a treatment mainstay. The conclusion of the NIHR evidence review was that both photochemotherapy and phototherapy were effective treatments for clearing psoriasis, although their comparative effectiveness was unknown. Despite the conclusions on efficacy, a number of issues were identified in the evidence review and several areas for future research were discussed to address these limitations. Trials focusing on comparative effectiveness, either between ultraviolet sources or between classes of treatment such as methotrexate versus phototherapy, were recommended to refine treatment algorithms. The need for better assessment of cost-effectiveness of therapies to consider systemic drug costs and costs of surveillance, as well as drug efficacy, were also noted. Overall, the authors concluded that phototherapy and photochemotherapy had important roles in psoriasis management and were standard therapeutic options for psoriasis offered in dermatology practices. The MAS evidence-based review focusing on the RCT trial evidence for ultraviolet phototherapy management of moderate-to-severe plaque psoriasis was performed as an update to the NIHR 2000 systemic review on treatments for severe psoriasis. In this review, an additional 26 RCT reports examining phototherapy or photochemotherapy for psoriasis were identified. Among the studies were two RCTs comparing ultraviolet wavelength sources, five RCTs comparing different forms of phototherapy, four RCTs combining phototherapy with prior spa saline bathing, nine RCTs combining phototherapy with topical agents, two RCTs combining phototherapy with the systemic immunosuppressive agents methotrexate or alefacept, one RCT comparing phototherapy with an additional light source (the excimer laser), and one comparing a combination therapy with phototherapy and psychological intervention involving simultaneous audiotape sessions on mindfulness and stress reduction. Two trials also examined the effect of treatment setting on effectiveness of phototherapy, one on inpatient versus outpatient therapy and one on outpatient clinic versus home-based phototherapy. Conclusions The conclusions of the MAS evidence-based review are outlined in Table ES1. In summary, phototherapy provides good control of clinical symptoms in the short term for patients with moderate-to-severe plaque-type psoriasis that have failed or are unresponsive to management with topical agents. However, many of the evidence gaps identified in the NIHR 2000 evidence review on psoriasis management persisted. In particular, the lack of evidence on the comparative effectiveness and/or cost-effectiveness between the major treatment options for moderate-to-severe psoriasis remained. The evidence on effectiveness and safety of longer term strategies for disease management has also not been addressed. Evidence for the safety, effectiveness, or cost-effectiveness of phototherapy delivered in various settings is emerging but is limited. In addition, because all available treatments for psoriasis – a disease with a high prevalence, chronicity, and cost – are palliative rather than curative, strategies for disease control and improvements in self-efficacy employed in other chronic disease management strategies should be investigated. Table ES1: RCT Evidence for Ultraviolet Phototherapy Treatment of Moderate-To-Severe Plaque Psoriasis Conclusion Evidence Level Phototherapy is an effective treatment for moderate-to-severe plaque psoriasis Moderate quality and adequate study evidence Narrow band PT is more effective than broad band PT for moderate-to-severe plaque psoriasis High quality but limited study evidence Oral-PUVA has a greater clinical response, requires less treatments and has a greater cumulative UV irradiation dose than UVB to achieve treatment effects for moderate-to-severe plaque psoriasis High quality and adequate study evidence Spa salt water baths prior to phototherapy did increase short term clinical response of moderate-to-severe plaque psoriasis but did not decrease cumulative UV irradiation dose High quality and adequate study evidence Addition of topical agents (vitamin D3 calcipotriol) to NB-UVB did not increase mean clinical response or decrease treatments or cumulative UV irradiation dose High quality and adequate study evidence Methotrexate prior to NB-UVB in high need psoriasis patients did significantly increase clinical response, decrease number of treatment sessions and decrease cumulative UV irradiation dose High quality study but limited study evidence Phototherapy following alefacept did increase early clinical response in moderate-to-severe plaque psoriasis Inadequate study evidence Effectiveness and safety of home NB-UVB phototherapy was not inferior to NB-UVB phototherapy provided in a clinic to patients with psoriasis referred for phototherapy. Treatment burden was lower and patient satisfaction was higher with home therapy and patients in both groups preferred future phototherapy treatments at home High quality study but limited study evidence Ontario Health System Considerations A 2006 survey of ultraviolet phototherapy services in Canada identified 26 phototherapy clinics in Ontario for a population of over 12 million. At that time, there were 177 dermatologists and 50 geographic regions in which 28% (14/50) provided phototherapy services. The majority of the phototherapy services were reported to be located in densely populated areas; relatively few patients living in rural communities had access to these services. The inconvenience of multiple weekly visits for optimal phototherapy treatment effects poses additional burdens to those with travel difficulties related to health, job, or family-related responsibilities. Physician OHIP billing for phototherapy services totaled 117,216 billings in 2007, representing approximately 1,800 patients in the province treated in private clinics. The number of patients treated in hospitals is difficult to estimate as physician costs are not billed directly to OHIP in this setting. Instead, phototherapy units and services provided in hospitals are funded by hospitals’ global budgets. Some hospitals in the province, however, have divested their phototherapy services, so the number of phototherapy clinics and their total capacity is currently unknown. Technological advances have enabled changes in phototherapy treatment regimens from lengthy hospital inpatient stays to outpatient clinic visits and, more recently, to an at-home basis. When combined with a telemedicine follow-up, home phototherapy may provide an alternative strategy for improved access to service and follow-up care, particularly for those with geographic or mobility barriers. Safety and effectiveness have, however, so far been evaluated for only one phototherapy home-based delivery model. Alternate care models and settings could potentially increase service options and access, but the broader consequences of the varying cost structures and incentives that either increase or decrease phototherapy services are unknown. Economic Analyses The focus of the current economic analysis was to characterize the costs associated with the provision of NB-UVB phototherapy for plaque-type, moderate-to-severe psoriasis in different clinical settings, including home therapy. A literature review was conducted and no cost-effectiveness (cost-utility) economic analyses were published in this area. Hospital, Clinic, and Home Costs of Phototherapy Costs for NB-UVB phototherapy were based on consultations with equipment manufacturers and dermatologists. Device costs applicable to the provision of NB-UVB phototherapy in hospitals, private clinics and at a patient’s home were estimated. These costs included capital costs of purchasing NB-UVB devices (amortized over 15-20 years), maintenance costs of replacing equipment bulbs, physician costs of phototherapy treatment in private clinics ($7.85 per phototherapy treatment), and medication and laboratory costs associated with treatment of moderate-to-severe psoriasis. NB-UVB phototherapy services provided in a hospital setting were paid for by hospitals directly. Phototherapy services in private clinic and home settings were paid for by the clinic and patient, respectively, except for physician services covered by OHIP. Indirect funding was provided to hospitals as part of global budgeting and resource allocation. Home therapy services for NB-UVB phototherapy were not covered by the MOHLTC. Coverage for home-based phototherapy however, was in some cases provided by third party insurers. Device costs for NB-UVB phototherapy were estimated for two types of phototherapy units: a “booth unit” consisting of 48 bulbs used in hospitals and clinics, and a “panel unit” consisting of 10 bulbs for home use. The device costs of the booth and panel units were estimated at approximately $18,600 and $2,900, respectively; simple amortization over 15 and 20 years implied yearly costs of approximately $2,500 and $150, respectively. Replacement cost for individual bulbs was about $120 resulting in total annual cost of maintenance of about $8,640 and $120 for booth and panel units, respectively. Estimated Total Costs for Ontario Average annual cost per patient for NB-UVB phototherapy provided in the hospital, private clinic or at home was estimated to be $292, $810 and $365 respectively. For comparison purposes, treatment of moderate-to-severe psoriasis with methotrexate and cyclosporin amounted to $712 and $3,407 annually per patient respectively; yearly costs for biological drugs were estimated to be $18,700 for alefacept and $20,300 for etanercept-based treatments. Total annual costs of NB-UVB phototherapy were estimated by applying average costs to an estimated proportion of the population (age 18 or older) eligible for phototherapy treatment. The prevalence of psoriasis was estimated to be approximately 2% of the population, of which about 85% was of plaque-type psoriasis and approximately 20% to 30% was considered moderate-to-severe in disease severity. An estimate of 25% for moderate-to-severe psoriasis cases was used in the current economic analysis resulting in a range of 29,400 to 44,200 cases. Approximately 21% of these patients were estimated to be using NB-UVB phototherapy for treatment resulting in a number of cases in the range between 6,200 and 9,300 cases. The average (7,700) number of cases was used to calculate associated costs for Ontario by treatment setting. Total annual costs were as follows: $2.3 million in a hospital setting, $6.3 million in a private clinic setting, and $2.8 million for home phototherapy. Costs for phototherapy services provided in private clinics were greater ($810 per patient annually; total of $6.3 million annually) and differed from the same services provided in the hospital setting only in terms of additional physician costs associated with phototherapy OHIP fees. Keywords Psoriasis, ultraviolet radiation, phototherapy, photochemotherapy, NB-UVB, BB-UVB PUVA PMID:23074532

  13. Pericardial rupture from blunt chest trauma

    PubMed Central

    Borrie, J.; Lichter, I.

    1974-01-01

    Borrie, J. and Lichter, I. (1974).Thorax, 29, 329-337. Pericardial rupture from blunt chest trauma. Pericardial rupture may occur in two distinct anatomical sites, namely the diaphragmatic pericardium and the pleuropericardium. They may be combined. The problems in each type are different. In ruptured diaphragmatic pericardium the rent may involve the pericardial cavity alone, or may extend into one or both adjoining pleural cavities. Upward herniation of abdominal viscera can occur, with or without strangulation. The presence of a pericardial rent may be suggested by diagnostic pneumoperitoneum, and chest films showing displaced abdominal viscera; its extent may be fully revealed only by thoracotomy. If the rent involves only the diaphragmatic pericardium without lateral spread into a pleural cavity, the presence of a rent may be revealed only by exploratory thoracotomy with pericardiotomy. In ruptured pleuropericardium the rent is usually vertical and may occur on either side, more usually on the left. It may be recognized on chest films in its early stages by the presence of intrapericardial air arising from associated lung trauma. There is serious risk of heart dislocation with or without strangulation. The defect must be surgically repaired and, because of pericardial retraction, it may require a fabric patch. Teflon fabric has proved to be a long-term satisfactory pericardial substitute. Two cases of each type of pericardial rupture are described and illustrate these points. Images PMID:4853582

  14. Restriction of bacteriophage plaque formation in Streptomyces spp.

    PubMed Central

    Cox, K L; Baltz, R H

    1984-01-01

    Several Streptomyces species that produce restriction endonucleases were characterized for their ability to propagate 10 different broad host range bacteriophages. Each species displayed a different pattern of plaque formation. A restrictionless mutant of S. albus G allowed plaque formation by all 10 phages, whereas the wild-type strain showed plaques with only 2 phages. DNA isolated from three of the phages was analyzed for the presence of restriction sites for Streptomyces species-encoded enzymes, and a very strong correlation was established between the failure to form plaques on Streptomyces species that produced particular restriction enzymes and the presence of the corresponding restriction sites in the phage DNA. Also, the phages that lacked restriction sites in their DNA generally formed plaques on the corresponding restriction endonuclease-producing hosts at high efficiency. The DNAs from the three phages analyzed also generally contained either many or no restriction sites for the Streptomyces species-produced enzymes, suggesting a strong evolutionary trend to either eliminate all or tolerate many restriction sites. The data indicate that restriction plays a major role in host range determination for Streptomyces phages. Analysis of bacteriophage host ranges of many other uncharacterized Streptomyces hosts has identified four relatively nonrestricting hosts, at least two of which may be suitable hosts for gene cloning. The data also suggest that several restriction systems remain to be identified in the genus Streptomyces. PMID:6086574

  15. Low copper and high manganese levels in prion protein plaques

    USGS Publications Warehouse

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

    2013-01-01

    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.

  16. Radiolabeled probes for imaging Alzheimer’s plaques

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    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.

  17. Statins, atherosclerosis regression and HDL: Insights from within the plaque.

    PubMed

    Feig, Jonathan E; Feig, Jessica L; Kini, Annapoorna S

    2015-06-15

    The idea that atheroma can regress is no longer a dream. We and others have discovered that decreasing the lipid content can directly lead to macrophage egress and plaque healing. The question, however, has remained as to how to translate these findings to the bedside. Taking advantage of imaging modalities such as intravascular ultrasound (IVUS) and near infrared spectroscopy (NIRS), we demonstrated in the YELLOW (Reduction in Yellow Plaque by Intensive Lipid Lowering Therapy) trial that short term treatment of high dose rosuvastatin treatment can lead to a decrease in lipid content in plaques. It is important to note that optical coherence tomography (OCT), a high resolution imaging modality, was not performed during the first study and therefore, only a very limited assessment of the effect of statin therapy on measures of plaque stabilization could be made. The YELLOW II trial is the first to our knowledge to determine whether these data can be extrapolated and how it relates to HDL function, alterations in macrophage gene expression, and plaque morphology. While tremendous progress has been made, our research serves as a reminder that angiography is simply luminography and it is features such as thin cap fibroatheroma and lipid burden, for example, that likely modulate the syndromes seen in clinical practice. Ongoing studies such as ours may provide novel pathways for diagnosis and therapy, with the ultimate goal of reducing the burden of cardiovascular disease. PMID:25897898

  18. ROPES eye plaque dosimetry: commissioning and verification of an ophthalmic brachytherapy treatment planning system

    NASA Astrophysics Data System (ADS)

    Poder, J.; Annabell, N.; Geso, M.; Alqathami, M.; Corde, S.

    2013-06-01

    In this study, the Plaque SimulatorTM eye plaque brachytherapy planning system was commissioned for ROPES eye plaques and Amersham Health model 6711 Iodine 125 seeds, using TG43-UI data. The brachytherapy module of the RADCALC® independent checking program was configured to allow verification of the accuracy of the dose calculated by Plaque SimulatorTM. Central axis depth dose distributions were compared and observed to agree to within 2% for all ROPES plaque models and depths of interest. Experimental measurements were performed with a customized PRESAGEm 3-D type dosimeter to validate the calculated depth dose distributions. Preliminary results have shown the effect of the stainless steel plaque backing decreases the measured fluorescence intensity by up to 25%, and 40% for the 15 mm and 10 mm diameter ROPES plaques respectively. This effect, once fully quantified should be accounted for in the Plaque SimulatorTM eye plaque brachytherapy planning system.

  19. 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)

    PubMed Central

    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

    2014-01-01

    Association between clinical factors and high-risk plaque features such as thin or ruptured cap, intra-plaque hemorrhage (IPH), 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 AIM-HIGH. A total of 214 subjects underwent carotid MRI and had acceptable image quality for assessment of plaque burden, tissue contents and MRI-modified AHA lesion type by a Core Lab. We found that 77% of subjects had carotid plaques, 52% had lipid-containing plaques, and 11% had advanced, AHA type-VI lesions with possible surface defect, IPH or mural thrombus. Type-VI lesions were associated with older age (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 %wall volume (%WV; 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 male gender (OR=3.2, p=0.02) and %WV (OR=3.8 per 1 SD, p<0.001), but, was negatively associated with diabetes (OR=0.4, p=0.02) and HDL-C levels (OR=0.7 per 1 SD, p=0.02). Increased %LRNC was associated with %WV (regression coefficient=0.36, p<0.001) and negatively associated with ApoA1 levels (regression coefficient=?0.20, p=0.03). In conclusions, older age, male gender, history of cerebrovascular disease, larger plaque burden, higher Lp(a), and lower HDL-C or ApoA1 have statistically significant associations with high-risk plaque features. Metabolic syndrome and diabetes showed negative associations in this population. PMID:25245415

  20. Acoustic levels of heavy truck tire ruptures.

    PubMed

    Wood, Matthew; Woodruff, William

    2013-05-01

    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

  1. On the rupture of DNA molecule

    NASA Astrophysics Data System (ADS)

    Mishra, R. K.; Modi, T.; Giri, D.; Kumar, S.

    2015-05-01

    Using Langevin dynamics simulations, we study effects of the shear force on the rupture of a double stranded DNA molecule. The model studied here contains two single diblock copolymers interacting with each other. The elastic constants of individual segments of diblock copolymer are considered to be different. We showed that the magnitude of the rupture force depends on whether the force is applied at 3' - 3' - ends or 5' - 5' - ends. Distributions of extension in hydrogen bonds and covalent bonds along the chain show the striking differences. Motivated by recent experiments, we have also calculated the variation of rupture force for different chain lengths. Results obtained from simulations have been validated with the analytical calculation based on the ladder model of DNA.

  2. Right ventricular hydatid cyst ruptured to pericardium.

    PubMed

    Sabzi, Feridoun; Vaziri, Siavoosh; Faraji, Reza

    2015-01-01

    Cardiac hydatidosis is rare presentation of body hydatidosis. Incidence of cardiac involvements range from 5% to 5% of patients with hydatid disease. Most common site of hydatid cyst in heart is interventricular septum and left ventricular free wall. Right ventricular free wall involvement by cyst that ruptured to pericardial cavity is very rare presentation of hydatid cyst. Cardiac involvement may have serious consequences such as rupture to blood steam or pericardial cavity. Both the disease and its surgical treatment carry a high complication rate, including rupture leading to cardiac tamponade, anaphylaxis and also death. In the present report, a 43-year-old man with constrictive pericarditis secondary to a pericardial hydatid cyst is described. PMID:26139761

  3. Postmyomectomic Uterine Rupture Despite Cesarean Section.

    PubMed

    Kacperczyk, Joanna; Bartnik, Paweł; Romejko-Wolniewicz, Ewa; Dobrowolska-Redo, Agnieszka

    2016-03-01

    Uterine fibroids (leiomyomas) are benign smooth muscle tumors of the uterus. Fibroids can develop anywhere within the muscular wall. Leiomyomas may be associated with infertility. Laparoscopic myomectomy is often used to remove symptomatic intramural or subserosal fibroids. Advantages of the procedure include short recovery time and minimal perioperative morbidity. At the same time, the multilayer suture technique is more complicated during laparoscopy. A rare but serious complication of laparoscopic myomectomies is uterine rupture. A brief review of the literature and a clinical example of a 33-year-old woman with history of infertility, laparoscopic myomectomies and uterine rupture followed by peripartum hemorrhage is presented. The treatment of leiomyomas is a challenge not only because of possible recurrence but also due to long-term consequences following successful myomectomy. Management of patients with uterine scars should include careful planning of the route of delivery, as the risk of rupture may be increased. PMID:26976991

  4. Component external leakage and rupture frequency estimates

    SciTech Connect

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

    1991-11-01

    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.

  5. Progression of abdominal aortic aneurysm towards rupture - refining clinical risk assessment using a fully coupled fluid-structure interaction method

    PubMed Central

    Xenos, Michalis; Labropoulos, Nicos; Rambhia, Suraj; Alemu, Yared; Einav, Shmuel; Tassiopoulos, Apostolos; Sakalihasan, Natzi; Bluestein, Danny

    2014-01-01

    Rupture of abdominal aortic aneurysm (AAA) is associated with high mortality rates. Risk of rupture is multi-factorial involving AAA geometric configuration, vessel tortuosity, and the presence of intraluminal pathology. Fluid structure interaction (FSI) simulations were conducted in Patient based computed tomography (CT) scans reconstructed geometries in order to monitor aneurysmal disease progression from normal aortas to non-ruptured and contained ruptured AAA (rAAA), and the AAA risk of rupture was assessed. Three groups of 8 subjects each were studied: 8 normal and 16 pathological (8 non-ruptured and 8 ruptured AAA). The AAA anatomical structures segmented included the blood lumen, intraluminal thrombus (ILT), vessel wall, and embedded calcifications. The vessel wall was described with anisotropic material model that was matched to experimental measurements of AAA tissue specimens. A statistical model for estimating the local wall strength distribution was employed to generate a map of a rupture potential index (RPI), representing the ratio between the local stress and local strength distribution. The FSI simulations followed a clear trend of increasing wall stresses from normal to pathological cases. The maximal stresses were observed in the areas where the ILT was not present, indicating a potential protective effect of the ILT. Statistically significant differences was observed between the peak systolic stress (PSS) and the peak stress at the mean arterial pressure (MAP) between the three groups. For the ruptured aneurysms, where the geometry of intact aneurysm was reconstructed, results of the FSI simulations clearly depicted maximum wall stress at the a-priori known location of rupture. The RPI mapping indicated several distinct regions of high RPI coinciding with the actual location of rupture. The FSI methodology demonstrates that the aneurysmal disease can be described by numerical simulations, as indicated by a clear trend of increasing aortic wall stresses in the studied groups, (normal aortas, AAAs and ruptured AAAs). Ultimately, the results demonstrate that FSI wall stress mapping and RPI can be used as a tool for predicting the potential rupture of an AAA by predicting the actual rupture location, complementing current clinical practice by offering a predictive diagnostic tool for deciding whether to intervene surgically or spare the patient from an unnecessary risky operation. PMID:25527320

  6. Assessment of neovascularization within carotid plaques in patients with ischemic stroke

    PubMed Central

    Huang, Pin-Tong; Chen, Cheng-Chun; Aronow, Wilbert S; Wang, Xiao-Tong; Nair, Chandra K; Xue, Nian-Yu; Shen, Xuedong; Li, Si-Yan; Huang, Fu-Guang; Cosgrove, David

    2010-01-01

    AIM: To assess neovascularization within human carotid atherosclerotic soft plaques in patients with ischemic stroke. METHODS: Eighty-one patients with ischemic stroke and 95 patients without stroke who had soft atherosclerotic plaques in the internal carotid artery were studied. The thickest soft plaque in each patient was examined using contrast-enhanced ultrasound. Time-intensity curves were collected from 5 s to 3 min after contrast injection. The neovascularization within the plaques in the internal carotid artery was evaluated using the ACQ software built into the scanner by 2 of the experienced investigators who were blinded to the clinical history of the patients. RESULTS: Ischemic stroke was present in 7 of 33 patients (21%) with grade?I?plaque, in 14 of 51 patients (28%) with grade II plaque, in 26 of 43 patients (61%) with grade III plaque, and in 34 of 49 patients (69%) with grade IV plaque (P < 0.001 comparing grade IV plaque with grade I plaque and with grade II plaque and P = 0.001 comparing grade III plaque with grade?I?plaque and with grade II plaque). Analysis of the time intensity curves revealed that patients with ischemic stroke had a significantly higher intensity of enhancement (IE) than those without ischemic stroke (P < 0.01). The wash-in time (WT) of plaque was significantly shorter in stroke patients (P < 0.05). The sensitivity and specificity for IE in the plaque were 82% and 80%, respectively, and for WT were 68% and 74%, respectively. There was no significant difference in the peak intensity or time to peak between the 2 groups. CONCLUSION: This study shows that the higher the grade of plaque enhancement, the higher the risk of ischemic stroke. The data suggest that the presence of neovascularization is a marker for unstable plaque. PMID:21160703

  7. Rupture Following Biceps-to-Triceps Tendon Transfer in Adolescents and Young Adults With Spinal Cord Injury:

    PubMed Central

    Merenda, Lisa A.; Rutter, Laure; Curran, Kimberly; Kozin, Scott H.

    2012-01-01

    Background: Tendon transfer surgery can restore elbow extension in approximately 70% of persons with tetraplegia and often results in antigravity elbow extension strength. However, we have noted an almost 15% rupture/attenuation rate. Objective: This investigation was conducted to analyze potential causes in adolescents/young adults with spinal cord injury (SCI) who experienced tendon rupture or attenuation after biceps-to-triceps transfer. Methods: Medical charts of young adults with SCI who underwent biceps-to-triceps transfer and experienced tendon rupture or attenuation were reviewed. Data collected by retrospective chart review included general demographics, surgical procedure(s), use and duration of antibiotic treatment, time from tendon transfer surgery to rupture/attenuation, and method of diagnosis. Results: Twelve subjects with tetraplegia (mean age, 19 years) who underwent biceps-to-triceps reconstruction with subsequent tendon rupture or attenuation were evaluated. Mean age at time of tendon transfer was 18 years (range, 14-21 years). A fluoroquinolone was prescribed for 42% (n=5) of subjects. Tendon rupture was noted in 67% (n=8), and attenuation was noted in 33% (n=4). Average length of time from surgery to tendon rupture/attenuation was 5.7 months (range, 3-10 months). Conclusion: Potential contributing causes of tendon rupture/attenuation after transfer include surgical technique, rehabilitation, co-contraction of the transfer, poor patient compliance, and medications. In this cohort, 5 subjects were prescribed fluoroquinolones that have a US Food and Drug Administration black box concerning tendon ruptures. Currently, all candidates for upper extremity tendon transfer reconstruction are counseled on the effects of fluoroquinolones and the potential risk for tendon rupture. PMID:23459326

  8. The association of hemoglobin A1c and high risk plaque and plaque extent assessed by coronary computed tomography angiography.

    PubMed

    Tomizawa, Nobuo; Inoh, Shinichi; Nojo, Takeshi; Nakamura, Sunao

    2016-03-01

    The objective of this study was to investigate the relationship of Hemoglobin A1c (HbA1c) and plaque characteristics including high risk plaque and plaque extent. We retrospectively examined 1079 consecutive coronary computed tomography (CT) angiography scans and the HbA1c results. We divided the patients into four groups by the HbA1c status: non-diabetic, ?6.0; borderline, 6.1-6.4; diabetic low, 6.5-7.1; diabetic high, >7.1. We determined segment involvement score >4 as extensive disease. High risk plaque was defined as two feature positive (FP) plaque which consists of positive remodeling (remodeling index >1.1) and low attenuation (<30 HU). Univariate and multivariate analysis including conventional cardiovascular risk factors, symptoms and medication was performed. Univariate analysis showed that diabetic patients as well as borderline patients were significantly related with 2FP plaque and extensive disease. Although the relationship of borderline patients and 2FP plaque was marginal in multivariate analysis [odds ratio (OR) 1.53, 95 % confidence interval (CI) 0.95-2.40, p = 0.07], the elevation of HbA1c was strongly associated with 2FP plaque (diabetic low, OR 2.19, 95 % CI 1.37-3.45, p < 0.005; diabetic high, OR 4.14, 95 % CI 2.57-6.67, p < 0.0005). The association of HbA1c elevation and extensive disease was quite similar between borderline and diabetic patients (borderline, OR 1.96, 95 % CI 1.29-2.95, p < 0.005; diabetic low, OR 1.94, 95 % CI 1.25-3.01, p < 0.005; diabetic high, OR 2.19, 95 % CI 1.39-3.43, p < 0.005). Patients with elevated HbA1c of >6.0 are potentially at risk for future cardiovascular events due to increased high risk plaque and extensive disease, even below the diabetic level of 6.5. Coronary CT could be used for risk stratification of these patients. PMID:26463885

  9. Prognostic factors of spontaneously ruptured hepatocellular carcinoma

    PubMed Central

    Han, Xiang-Jun; Su, Hong-Ying; Shao, Hai-Bo; Xu, Ke

    2015-01-01

    AIM: To evaluate the prognostic factors in patients with spontaneously ruptured hepatocellular carcinoma (HCC). METHODS: Seventy-nine patients experiencing spontaneous rupture of HCC between April 2004 and August 2014 were enrolled in this study. The clinical features, treatment modalities and outcomes were reviewed. The statistical methods used in this work included univariate analysis, Kaplan-Meier survival analysis with log-rank tests, and multivariate analysis using a Cox regression hazard model. RESULTS: Of the 79 patients with HCC rupture, 17 (21.5%) underwent surgery, 32 (40.5%) underwent transarterial embolization (TAE), and 30 (38%) received conservative treatment. The median survival time was 125 d, and the mortality rate at 30 d was 27.8%. Multivariate analysis revealed that lesion length (HR = 1.46, P < 0.001), lesion number (HR = 1.37, P = 0.042), treatment before tumor rupture (HR = 4.36, P = 0.019), alanine transaminase levels (HR = 1.0, P = 0.011), bicarbonate levels (HR = 1.18, P < 0.001), age (HR = 0.96, P = 0.026), anti-tumor therapy during the follow-up period (HR = 0.21, P = 0.008), and albumin levels (HR = 0.89, P = 0.010) were independent prognostic factors of survival after HCC rupture. The Barcelona-Clinic Liver Cancer (BCLC) stage was also an important prognostic factor; the median survival times for BCLC stages A, B and C were 251, 175 and 40 d, respectively (P < 0.001). CONCLUSION: Anti-tumor therapy during the follow-up period, without a history of anti-tumor therapy prior to HCC rupture, small tumor length and number, and early BCLC stage are the most crucial predictors associated with satisfactory overall survival. Other factors play only a small role in overall survival. PMID:26139994

  10. Linguine sign in musculoskeletal imaging: calf silicone implant rupture.

    PubMed

    Duryea, Dennis; Petscavage-Thomas, Jonelle; Frauenhoffer, Elizabeth E; Walker, Eric A

    2015-08-01

    Imaging findings of breast silicone implant rupture are well described in the literature. On MRI, the linguine sign indicates intracapsular rupture, while the presence of silicone particles outside the fibrous capsule indicates extracapsular rupture. The linguine sign is described as the thin, wavy hypodense wall of the implant within the hyperintense silicone on T2-weighted images indicative of rupture of the implant within the naturally formed fibrous capsule. Hyperintense T2 signal outside of the fibrous capsule is indicative of an extracapsular rupture with silicone granuloma formation. We present a rare case of a patient with a silicone calf implant rupture and discuss the MRI findings associated with this condition. PMID:25577259

  11. Radiation regression patterns after cobalt plaque insertion for retinoblastoma

    SciTech Connect

    Buys, R.J.; Abramson, D.H.; Ellsworth, R.M.; Haik, B.

    1983-08-01

    An analysis of 31 eyes of 30 patients who had been treated with cobalt plaques for retinoblastoma disclosed that a type I radiation regression pattern developed in 15 patients; type II, in one patient, and type III, in five patients. Nine patients had a regression pattern characterized by complete destruction of the tumor, the surrounding choroid, and all of the vessels in the area into which the plaque was inserted. This resulting white scar, corresponding to the sclerae only, was classified as a type IV radiation regression pattern. There was no evidence of tumor recurrence in patients with type IV regression patterns, with an average follow-up of 6.5 years, after receiving cobalt plaque therapy. Twenty-nine of these 30 patients had been unsuccessfully treated with at least one other modality (ie, light coagulation, cryotherapy, external beam radiation, or chemotherapy).

  12. Proton MR spectroscopy of gadolinium-enhanced multiple sclerosis plaques.

    PubMed

    Narayana, P A; Wolinsky, J S; Jackson, E F; McCarthy, M

    1992-01-01

    Magnetic resonance (MR) imaging and proton MR spectroscopy were performed in 14 patients with clinically definite multiple sclerosis (MS). Prominent resonances in the 0.5-2.0-ppm region were seen in the spectra of six of nine gadopentetate dimeglumine-enhanced plaques in seven patients. These resonances were presumed to originate in lipids and other myelin breakdown products. Similar resonances were detected in only seven of 21 unenhancing plaques. The more frequent presence of such signals in the gadolinium-enhanced regions indicates that myelin breakdown is often associated with the inflammation that occurs in early stages of MS plaque evolution. It remains uncertain, however, whether active inflammation as indicated by gadolinium enhancement is a necessary precursor of myelin breakdown as detected at MR spectroscopy. Quantitative spectral analysis did not indicate statistically significant differences in N-acetyl aspartate and choline levels relative to creatine plus phosphocreatine between healthy volunteers and MS patients. PMID:1627860

  13. Gastric rupture after bag-mask-ventilation

    PubMed Central

    Bednarz, Stephan; Filipovic, Miodrag; Schoch, Otto; Mauermann, Eckhard

    2015-01-01

    A 42 year old woman underwent bronchoscopy with procedural propofol sedation. During the procedure, the patient suffered respiratory arrest, and bag-mask ventilation was initiated. During forced mask ventilation, abdominal distention occurred. Even after correct placement of an endotracheal and a nasogastric tube, high inspiratory pressures persisted. The abdominal CT scan revealed a high amount of intraperitoneal free air. An emergent laparotomy confirmed a stomach rupture. Immediately after opening of the peritoneal cavity, peak ventilatory pressures decreased. In this case forceful bag-mask ventilation led to air insufflation into the stomach, increasing gastric pressure, and consecutive stomach rupture. PMID:26744639

  14. COMPARISON OF CLADDING CREEP RUPTURE MODELS

    SciTech Connect

    P. Macheret

    2000-06-12

    The objective of this calculation is to compare several creep rupture correlations for use in calculating creep strain accrued by the Zircaloy cladding of spent nuclear fuel when it has been emplaced in the repository. These correlations are used to calculate creep strain values that are then compared to a large set of experimentally measured creep strain data, taken from four different research articles, making it possible to determine the best fitting correlation. The scope of the calculation extends to six different creep rupture correlations.

  15. Thoracic Outlet Syndrome Following Breast Implant Rupture

    PubMed Central

    Caplash, Yugesh; Giri, Pratyush; Kearney, Daniel; Wagstaff, Marcus

    2015-01-01

    Summary: We present a patient with bilateral breast implant rupture who developed severe locoregional silicone granulomatous lymphadenopathy. Poly Implant Prothese silicone implants had been used for bilateral breast augmentation 5 years prior. Extracapsular implant rupture and bilateral axillary lymphadenopathy indicated explantation, capsulectomy, and selective lymph node excision. Histology demonstrated silicone lymphadenopathy with no evidence of malignancy. Over the subsequent 12 months, she developed progressive locoregional lymphadenopathy involving bilateral cervical, axillary, and internal mammary groups, resulting in bilateral thoracic outlet syndrome. We report the unusual presentation, progression, and the ultimate surgical management of this patient. PMID:25878942

  16. Tendon ruptures: mallet, flexor digitorum profundus.

    PubMed

    Yeh, Peter C; Shin, Steven S

    2012-08-01

    Mallet injuries are the most common closed tendon injury in the athlete. Flexor digitorum profundus ruptures are rare in baseball, but are common injuries in contact sports. The diagnosis for each condition is based on clinical examination, although radiographs should be evaluated for a possible bony component. Treatment for mallet injury depends on the athlete's goals of competition and understanding of the consequences of any treatment chosen. Gripping, throwing, and catching would be restricted or impossible with the injured finger immobilized. Treatment of FDP ruptures is almost always surgical and requires reattachment of the torn tendon to the distal phalanx. PMID:22883898

  17. Rupture energy of a pendular liquid bridge

    NASA Astrophysics Data System (ADS)

    Pitois, O.; Moucheront, P.; Chateau, X.

    2001-09-01

    We propose a simple expression for the rupture energy of a pendular liquid bridge between two spheres, taking into account capillary and viscous (lubrication) forces. In the case of capillary forces only, the results are in accordance with curve fitting expressions proposed by Simons et al. [2] and Willett et al. [5]. We performed accurate measurements of the force exerted by liquid bridges between two spheres. Experimental results are found to be close to theoretical values. A reasonable agreement is also found in the presence of viscous forces. Finally, for small bridge volumes, the rupture criterion given by Lian et al. [10] is modified, taking into account additional viscous effects.

  18. Spontaneous Achilles tendon rupture in alkaptonuria.

    PubMed

    Alajoulin, Omar A; Alsbou, Mohammed S; Ja'afreh, Somayya O; Kalbouneh, Heba M

    2015-12-01

    Alkaptonuria (AKU) is a rare inborn metabolic disease characterized by accumulation of homogentisic acid (HGA). Excretion of HGA in urine causes darkening of urine and its deposition in connective tissues causes dark pigmentation (ochronosis), early degeneration of articular cartilage, weakening of the tendons, and subsequent rupture. In this case report, we present a rare case of a patient presented with unilateral spontaneous rupture of Achilles tendon due to AKU. The patient developed most of the orthopedic manifestations of the disease earlier than typical presentations. Alkaptonuria patients should avoid strenuous exercises and foot straining especially in patients developing early orthopedic manifestations. PMID:26620992

  19. Spontaneous Achilles tendon rupture in alkaptonuria

    PubMed Central

    Alajoulin, Omar A.; Alsbou, Mohammed S.; Ja’afreh, Somayya O.; Kalbouneh, Heba M.

    2015-01-01

    Alkaptonuria (AKU) is a rare inborn metabolic disease characterized by accumulation of homogentisic acid (HGA). Excretion of HGA in urine causes darkening of urine and its deposition in connective tissues causes dark pigmentation (ochronosis), early degeneration of articular cartilage, weakening of the tendons, and subsequent rupture. In this case report, we present a rare case of a patient presented with unilateral spontaneous rupture of Achilles tendon due to AKU. The patient developed most of the orthopedic manifestations of the disease earlier than typical presentations. Alkaptonuria patients should avoid strenuous exercises and foot straining especially in patients developing early orthopedic manifestations. PMID:26620992

  20. Pectoralis major tendon rupture. Surgical procedures review.

    PubMed Central

    Merolla, Giovanni; Paladini, Paolo; Campi, Fabrizio; Porcellini, Giuseppe

    2012-01-01

    Summary Pectoralis major (PM) muscle is the powerful dynamic stabiliser of the shoulder that acts as a flexor, adductor and internal rotator. The rupture of the PM tendon is a relatively rare injury that was firstly described in a French boy by Patissier in 1822 and later, in 1861, by Letenneur who reported another similiar case. To date, over 200 cases have been published. In this article we describe the clinical anatomy and the mechanism of injuries of PM and we review the surgical procedures for acute and chronic ruptures. PMID:23738281

  1. Bifurcation analysis of a model for atherosclerotic plaque evolution

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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 (σ). 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.

  2. Effects of plaque lengths on stent surface roughness.

    PubMed

    Syaifudin, Achmad; Takeda, Ryo; Sasaki, Katsuhiko

    2015-01-01

    The physical properties of the stent surface influence the effectiveness of vascular disease treatment after stent deployment. During the expanding process, the stent acquires high-level deformation that could alter either its microstructure or the magnitude of surface roughness. This paper constructed a finite element simulation to observe the changes in surface roughness during the stenting process. Structural transient dynamic analysis was performed using ANSYS, to identify the deformation after the stent is placed in a blood vessel. Two types of bare metal stents are studied: a Palmaz type and a Sinusoidal type. The relationship between plaque length and the changes in surface roughness was investigated by utilizing three different length of plaque; plaque length longer than the stent, shorter than the stent and the same length as the stent. In order to reduce computational time, 3D cyclical and translational symmetry was implemented into the FE model. The material models used was defined as a multilinear isotropic for stent and hyperelastic for the balloon, plaque and vessel wall. The correlation between the plastic deformation and the changes in surface roughness was obtained by intermittent pure tensile test using specimen whose chemical composition was similar to that of actual stent material. As the plastic strain is achieved from FE simulation, the surface roughness can be assessed thoroughly. The study found that the plaque size relative to stent length significantly influenced the critical changes in surface roughness. It was found that the length of stent which is equal to the plaque length was preferable due to the fact that it generated only moderate change in surface roughness. This effect was less influential to the Sinusoidal stent. PMID:25813957

  3. Earthquake Stress Drop in Rupture Patches and Rupture Barriers on Gofar Transform Fault, East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Moyer, P. A.; Boettcher, M. S.; McGuire, J. J.; Collins, J. A.

    2014-12-01

    The largest earthquakes on mid-ocean ridge transform faults (RTFs) exhibit the most systematic behaviors known in seismology. On the fast slipping Gofar transform fault on the East Pacific Rise (EPR), Mw ~6.0 earthquakes occur every ~5 years and repeatedly rupture the same asperities (fault patches), suggesting that the intervening fault segments (rupture barriers) stop the propagation of the largest earthquakes. In 2008, an ocean bottom seismometer (OBS) deployment captured the end of a seismic cycle on Gofar transform fault [McGuire et al., 2012]. We determine stress drop for earthquakes recorded during this experiment to investigate how the source properties of moderate sized earthquakes (3.0 < Mw < 5.5) differ between the rupture patch and rupture barrier fault segments. The OBS experiment on Gofar transform fault recorded an extensive foreshock sequence localized within a 10 km rupture barrier, the Mw 6.0 mainshock and its aftershocks that occurred in a ~10 km rupture patch, and an earthquake swarm that was located in a second rupture barrier adjacent to the ridge-transform intersection. Using waveforms recorded with a sample rate of 50 Hz on the OBS accelerometers, we calculate stress drop using the Madariaga [1976] circular crack model, with the corner frequency derived from an empirical Green's function (EGF) method, and seismic moment obtained by fitting an omega-squared source model to the low frequency amplitude of individual event spectra. Results for ~300 earthquakes in the foreshock, aftershock, and swarm zones have a range of stress drops from 0.2 to 50 MPa. Values for the best constrained 10% of earthquakes show a weighted average stress drop in the aftershock zone that is more than twice the weighted average stress drop in the foreshock zone (3.5 MPa and 1.1 MPa, respectively). These variations in earthquake stress drop reflect systematic differences in along strike fault zone properties between rupture patches and rupture barriers on Gofar transform fault.

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

    PubMed Central

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

    2016-01-01

    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, which reconstructs elasticity maps (or modulograms) of atheroma plaques from the estimation of strain fields. In the present in vitro experimental study, conducted on PVA-C 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 values and sensitivities 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. PMID:20826899

  5. 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)

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

    2010-10-01

    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.

  6. DETAIL OF PLAQUE COMMEMORATING THE JULY/ AUGUST 1958 VOYAGE OF ...

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

    DETAIL OF PLAQUE COMMEMORATING THE JULY/ AUGUST 1958 VOYAGE OF THE USS NAUTILUS (SSN-571) TO THE NORTH POLE. NOTE: THIS PLAQUE IS NOT LOCATED AT WHARFS S13-S19; IT IS AT THE SUBMARINE MEMORIAL PARK, ABOUT 1,000' SOUTH OF THE WHARFS. THE LOCATION AND ORIENTATION OF THIS PHOTO IS NOT SHOWN ON THE PHOTO KEY MAP - U.S. Naval Base, Pearl Harbor, Additional Piers and Quay Walls, S13 to S19, Northeast end of Magazine Loch, Pearl City, Honolulu County, HI

  7. Dosimetric study of the 15 mm ROPES eye plaque

    SciTech Connect

    Granero, D.; Perez-Calatayud, J.; Ballester, F.; Casal, E.; Frutos, J.M. de

    2004-12-01

    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.

  8. Multispectral optoacoustic tomography resolves smart probe activation in vulnerable plaques

    NASA Astrophysics Data System (ADS)

    Razansky, Daniel; Harlaar, Niels J.; Hillebrands, Jan-Luuk; Taruttis, Adrian; Herzog, Eva; Zeebregts, Clark; van Dam, Goitzen; Ntziachristos, Vasilis

    2011-03-01

    In this work, we show, for the first time to our knowledge, that multispectral optoacoustic tomography (MSOT) can deliver high resolution images of activatable molecular probe's distribution, sensitive to matrix metalloproteinases (MMP), deep within optically scattering human carotid specimen. It is further demonstrated that this method can be used in order to provide accurate maps of vulnerable plaque formations in atherosclerotic disease. Moreover, optoacoustic images can simultaneously show the underlining plaque morphology for accurate localization of MMP activity in three dimensions. This performance directly relates to small animal screening applications and to clinical potential as well.

  9. Method of making a light weight battery plaque

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    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%.

  10. [Papillary Muscle Rupture after Repair of Ischemic Left Ventricular Free Wall Rupture; Report of a Case].

    PubMed

    Kurumisawa, Soki; Kaminishi, Yuichirou; Akutsu, Hirohiko; Takazawa, Ippei; Aizawa, Kei; Misawa, Yoshio

    2015-11-01

    A 67-year-old man experienced acute inferior myocardial infarction. Echocardiography and computed tomography showed massive pericardial effusion. He underwent emergency operation for ischemic ventricular free wall rupture. During the operation, an oozing type rupture was found on the inferior wall and the bleeding was completely controlled by applying fibrin glue sheets. On the 5th day after the operation, ventricular tachycardia appeared with hemodynamic deterioration. Echocardiography showed a ruptured posteromedial papillary muscle with massive mitral regurgitation. Intra-aortic balloon pumping was introduced and emergency repair operation was performed. The mitral valve was replaced with a bioprosthetic valve. The postoperative course was uneventful. PMID:26555919

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

    PubMed Central

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

    2008-01-01

    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

  12. Feasibility of diagnosing unstable plaque in patients with acute coronary syndrome using iMap-IVUS*

    PubMed Central

    LIU, Jian; WANG, Zhao; WANG, Wei-min; LI, Qi; MA, Yu-liang; LIU, Chuan-fen; LU, Ming-yu; ZHAO, Hong

    2015-01-01

    Objective: To compare the plaque composition between stable and unstable plaques, characterize unstable plaque by using iMap-intravascular ultrasound (IVUS), and quantify the diagnostic criteria for unstable plaque. Methods: Thirty-three acute coronary syndrome (ACS) patients who had undergone coronary angiography and IVUS from February 19, 2014 to December 19, 2014 at Peking University People’s Hospital were enrolled in the study. Baseline data were collected. The patients were divided into two groups according to their gray-scale IVUS imaging, stable plaque and unstable plaque. A difference-in-difference evaluation was performed using the baseline data and off-line iMap imaging results between the two groups. A receiver operating characteristic (ROC) curve was constructed to obtain the optimal cut-off value to diagnose unstable plaque. Results: Percentages of fibrotic and necrotic tissues, absolute values of lipidic, necrotic, and calcified tissues, and plaque burden were independent predictors for unstable plaque. Absolute necrotic area was the best predictor and exhibited the highest diagnostic value for plaque vulnerability (area under the curve (AUC)=0.806, P=0.000, 95% CI (0.718, 0.894)). The cut-off score for predicting unstable plaque was 4.0 mm2. Conclusions: This study attempted to propose a cut-off value based on absolute necrotic area using iMap-IVUS to predict plaque vulnerability in patients with ACS. This score might provide a valuable reference for diagnosing unstable plaque. PMID:26537210

  13. Effects of extracellular plaque components on the chlorhexidine sensitivity of strains of Streptococcus mutans and human dental plaque

    SciTech Connect

    Wolinsky, L.E.; Hume, W.R.

    1985-08-01

    An in vitro study was undertaken to determine the effects of sucrose-derived extracellular plaque components on the sensitivity of selected oral bacteria to chlorhexidine (CX). Cultures of Streptococcus mutans HS-6, OMZ-176, Ingbritt C, 6715-wt13, and pooled human plaque were grown in trypticase soy media with or without 1% sucrose. The sensitivity to CX of bacteria grown in each medium was determined by fixed-time exposure to CX and subsequent measurement of /sup 3/H-thymidine uptake. One-hour exposure to CX at concentrations of 10(-4) M (0.01% w/v) or greater substantially inhibited subsequent cellular division among all the S. mutans strains and human plaque samples tested. An IC50 (the CX concentration which depressed /sup 3/H-thymidine incorporation to 50% of control level) of close to 10(-4) M was noted for S. mutans strains HS-6, OMZ-176, and 6715-wt13 when grown in the presence of sucrose. The same strains grown in cultures without added sucrose showed about a ten-fold greater sensitivity to CX (IC50 close to 10(-5) M). A three-fold difference was noted for S. mutans Ingbritt C. Only a slight increase in the IC50 was noted for the plaque samples cultured in sucrose-containing media, but their threshold for depression of /sup 3/H-thymidine uptake by CX was lower than that for the sucrose-free plaque samples. The study showed that extracellular products confer some protection against CX to the bacteria examined, and provided an explanation for the disparity between clinically-recommended concentrations for plaque suppression and data on in vitro susceptibility.

  14. The Inclusion of Arbitrary Load Histories in the Strength Decay Model for Stress Rupture

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2014-01-01

    Stress rupture is a failure mechanism where failures can occur after a period of time, even though the material has seen no increase in load. Carbon/epoxy composite materials have demonstrated the stress rupture failure mechanism. In a previous work, a model was proposed for stress rupture of composite overwrap pressure vessels (COPVs) and similar composite structures based on strength degradation. However, the original model was limited to constant load periods (holds) at constant load. The model was expanded in this paper to address arbitrary loading histories and specifically the inclusions of ramp loadings up to holds and back down. The broadening of the model allows for failures on loading to be treated as any other failure that may occur during testing instead of having to be treated as a special case. The inclusion of ramps can also influence the length of the "safe period" following proof loading that was previously predicted by the model. No stress rupture failures are predicted in a safe period because time is required for strength to decay from above the proof level to the lower level of loading. Although the model can predict failures during the ramp periods, no closed-form solution for the failure times could be derived. Therefore, two suggested solution techniques were proposed. Finally, the model was used to design an experiment that could detect the difference between the strength decay model and a commonly used model for stress rupture. Although these types of models are necessary to help guide experiments for stress rupture, only experimental evidence will determine how well the model may predict actual material response. If the model can be shown to be accurate, current proof loading requirements may result in predicted safe periods as long as 10(13) years. COPVs design requirements for stress rupture may then be relaxed, allowing more efficient designs, while still maintaining an acceptable level of safety.

  15. [Dual source computed tomography in analysis of significance and morphology carotid plaques].

    PubMed

    Witkiewicz, Wojciech; Klimeczek, Piotr; Iwanowski, Wojciech; Pasicka, Bernadetta; Do?ega-Kozierowski, Bartosz; Drelichowski, Stanis?aw; Dy?, Krzysztof; Zaleska-Dorobisz, Urszula

    2013-01-01

    One of the most common causes of stroke is carotid atherosclerosis, stroke affects about 60 thousand Polish people each year and about 27% of them die within a year. About 72%-86% are ischemic strokes, whereas intracerebral or subarachnoid haemorrhages account for about 9-18% of strokes. Stroke is the third most common cause of death worldwide, after heart disease and cancer, and the most often cause of chronic disability in people over 40. Carotid atherosclerosis is one of the most important stroke risk factors. The degree of stenosis is a standard parameter usually used in risk assessment. It was shown that patients with stenosis greater than 70% undergoing endarterectomy achieve the best results in reducing the risk of stroke compared with pharmacotherapy. However, it was found that in the general population of people over 64 the stenosis greater than 70% occurred in 10% of patients, while changes below 70% were very common and appeared in 70% of men and 60% of women. For this reason, the importance of atherosclerotic plaque morphology in the risk assessment is growing. Histopathological and ultrasound (intravascular ultrasound) morphological changes in the composition of the atherosclerotic plaque lead to the creation of the vulnerable plaque concept. Stroke risk seems to be connected with certain morphological features of the plaque, such as thin fibrous cap, lipid core, or ulceration. Ulceration is especially important, as 30% of those patients develop neurological symptoms within 2 years. On the other hand strong plaque calcification, particularly superficial, appears to pose lower risk. Ultrasound imaging of carotid arteries is currently the most widely used non-invasive diagnostic method for detecting and assessing the extent of carotid atherosclerosis. However, apart from undeniable advantages it also has its limitations such as the scope of the imaging and lower sensitivity and specificity in the evaluation of carotid stenosis in relation to magnetic resonance imaging and computed tomography (CT) as showed in metaanalyses from multicenter research (e.g. Chapel et al. metaanalysis). Previous studies using CT demonstrated the suitability of this method in the evaluation of morphology and significance of carotid arteries stenosis. Recent introduction of dual source multidetector computed tomography (DSCT) is a next technological step increasing the usefulness of CT in the assessment of plaque morphology. Due to simultaneous operation of 2 lamps the DSCT uses two concurrent X-ray sources (80 kv and 80 kV or 120 kV or 140 kV) to obtain different radiation absorption coefficients for a given tissue (in Hounsfield units). This allows for better tissue differentiation and advanced image processing, e.g. easy removal of bone parts for better visualization of vascular areas. This method also facilitates more accurate visualization of the lipid core and ulcerations. However, it should be emphasized that still relatively low spatial resolution of this method (0.6 mm) is a serious limitation to an accurate analysis of small structures, such as the components of the atherosclerotic plaque. Therefore, further comparative studies with other invasive diagnostic methods are necessary to improve the imaging protocols. PMID:24003664

  16. D-Zero Cryostat Supplemental Rupture Disc

    SciTech Connect

    Mulholland, G.T.; /Fermilab

    1987-08-03

    The common relief and rupture disc vent line requires a double disc assembly with vented interspace for accurate disc burst pressures. The first disc must take pump and purge vacuum loading, but be set to operate at 110% of the MAWP, 18.3 psig (ASME code). The available solution is 18.3 psig with a burst tolerance of +/- psig. The interspace should be locally vented by a flow limiting vent valve to decouple the vent line backpressure from the vessel rupture disc. The second disc must take the worst case vent line backpressure, the steady state value found in D-Zero engineering note 3740.000-EN-63 with all three cryostats simultaneously venting at the fire condition into the 4-inch x 6-inch and 6-inch x 8-inch sections. This value is less than 2 psid. The maximum rupture value for the second disc must be less than the minimum rupture value for the first disc less 2 psid i.e. < 16.3.

  17. Surgical Management of Spontaneous Ruptured Hepatocellular Adenoma

    PubMed Central

    Ribeiro Junior, Marcelo Augusto Fontenelle; Chaib, Eleazar; Saad, William Abrão; D’Albuquerque, Luiz Augusto Carneiro; Cecconello, Ivan

    2009-01-01

    AIMS Spontaneous ruptured hepatocellular adenoma (SRHA) is a rare life-threatening condition that may require surgical treatment to control hemorrhaging and also stabilize the patient. We report a series of emergency surgeries performed at our institution for this condition. METHODS We reviewed medical records and radiology files of 28 patients (from 1989 to 2006) with a proven diagnosis of hepatocellular adenoma (HA). Three (10.7%) of 28 patients had spontaneous ruptured hepatocellular adenoma, two of which were associated with intrahepatic hemorrhage while one had intraperitoneal bleeding. Two patients were female and one was male. Both female patients had a background history of oral contraceptive use. Sudden abdominal pain associated with hemodynamic instability occurred in all patients who suffered from spontaneous ruptured hepatocellular adenoma. The mean age was 41.6 years old. The preoperative assessment included liver function tests, ultrasonography and computed tomography. RESULTS The surgical approaches were as follows: right hemihepatectomy for controlling intraperitoneal bleeding, and right extended hepatectomy and non-anatomic resection of the liver for intrahepatic hemorrhage. There were no deaths, and the postoperative complications were bile leakage and wound infection (re-operation), as well as intraperitoneal abscess (re-operation) and pleural effusion. CONCLUSION Spontaneous ruptured hepatocellular adenoma may be treated by surgery for controlling hemorrhages and stabilizing the patient, and the decision to operate depends upon both the patient’s condition and the expertise of the surgical team. PMID:19690662

  18. 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...

  19. Surgical resection of ruptured fibrolamellar hepatocellular carcinoma.

    PubMed

    Minutolo, Vincenzo; Licciardello, Alessio; Arena, Manuel; Minutolo, Orazio; Lanteri, Raffaele; Arena, Goffredo

    2013-01-01

    Fibrolamellar hepatocellular carcinoma (FLH) is a rare primary tumor of the liver, which typically arises from noncirrhotic livers and affects patients below the age of 35. We report on a 29-year-old male patient who presented with a ruptured FLH and was treated with surgical resection. Options for treatment and review of the management are described. PMID:23956918

  20. Surgical Resection of Ruptured Fibrolamellar Hepatocellular Carcinoma

    PubMed Central

    Minutolo, Vincenzo; Licciardello, Alessio; Arena, Manuel; Minutolo, Orazio; Lanteri, Raffaele; Arena, Goffredo

    2013-01-01

    Fibrolamellar hepatocellular carcinoma (FLH) is a rare primary tumor of the liver, which typically arises from noncirrhotic livers and affects patients below the age of 35. We report on a 29-year-old male patient who presented with a ruptured FLH and was treated with surgical resection. Options for treatment and review of the management are described. PMID:23956918

  1. Spontaneous splenic rupture resulted from infectious mononucleosis

    PubMed Central

    Won, Andy C.M.; Ethell, Anthony

    2011-01-01

    INTRODUCTION Infectious mononucleosis is common among young adults and teenagers. However, spontaneous rupture of spleen secondary to IM is rare and it is the most frequent cause of death in infectious mononucleosis. PRESENTATION OF CASE A previously healthy 16-year-old girl presented with a one-week history of sore throat, non-productive cough, fever, malaise and a positive Monospot test. Prior to transfer to the hospital, she had two syncopal episodes and a complaint of abdominal pain at home. Clinical examination revealed that she was febrile and mildly tachycardic with an evidence of localised peritonism on her left upper quadrant. Urgent abdominal ultrasound and computed tomography scan showed subcapsular haematoma with a significant amount of complex fluid within the abdominal cavity, especially the left flank. Emergency laparotomy was performed and a moderate amount of haemoperitoneum was evacuated. The spleen was found grossly enlarged with a haematoma identified on the ruptured capsule. Splenectomy was performed and peritoneal cavity was washed out meticulously prior to the closure of the abdominal wall. DISCUSSION Despite the fact that infectious mononucleosis is a self-limiting disease, it may cause serious and lethal complications. The best treatment of splenic rupture secondary to infectious mononucleosis has been controversial but it is mainly based on the haemodynamical status of the patient and the experience of the treating surgeon. CONCLUSION Spontaneous rupture of spleen secondary to IM can be lethal in those patients with high possibility of deterioration with conservative management, thus timely surgical intervention is required. PMID:22288057

  2. Bond-rupture immunosensors--a review.

    PubMed

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

    2008-07-15

    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

  3. [Splenic rupture--a skateboard accident].

    PubMed

    Kruse, P

    1990-03-01

    A 13-year-old boy presented with persisting abdominal pain after a skateboard accident. Primary clinical and laboratory findings disclosed no signs of intra abdominal bleeding. Ultrasound scanning indicated rupture of the spleen which was confirmed by acute exploratory laparotomy. PMID:2321288

  4. Laparoscopic splenectomy for atraumatic splenic rupture.

    PubMed

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

    2011-01-01

    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

  5. Primary gastric rupture in 47 horses (1995–2011)

    PubMed Central

    Winfield, Laramie S.; Dechant, Julie E.

    2015-01-01

    The purpose of this retrospective case-control study was to identify factors associated with primary gastric rupture and to investigate if there were differences between etiologies of primary gastric rupture. Compared to the general colic population, Quarter horses were under-represented and Friesians and draft breeds were over-represented in 47 cases of primary gastric ruptures. Horses with primary gastric rupture typically presented with severe clinical and clinicopathological derangements. There were 24 idiopathic gastric ruptures, 20 gastric impaction associated ruptures, and 3 perforating gastric ulcers. Thoroughbred horses were over-represented in the idiopathic gastric rupture group compared to other breeds and etiologies. This study suggests the presence of important breed predispositions for development of gastric rupture. Further study is necessary to identify if these predispositions are associated with management factors or breed-specific disorders. PMID:26345205

  6. Source rupture process of the 2011 Fukushima-ken Hamadori earthquake: how did the two subparallel faults rupture?

    NASA Astrophysics Data System (ADS)

    Tanaka, Miho; Asano, Kimiyuki; Iwata, Tomotaka; Kubo, Hisahiko

    2014-12-01

    The 2011 Fukushima-ken Hamadori earthquake (MW 6.6) occurred about a month after the 2011 Great Tohoku earthquake (MW 9.0), and it is thought to have been induced by the 2011 Tohoku earthquake. After the 2011 Hamadori earthquake, two subparallel faults (the Itozawa and Yunodake faults) were identified by field surveys. The hypocenter was located nearby the Itozawa fault, and it is probable that the Itozawa fault ruptured before the Yunodake fault rupture. Here, we estimated the source rupture process of the 2011 Hamadori earthquake using a model with two subparallel faults based on strong motion data. The rupture starting point and rupture delay time of the Yunodake fault were determined based on Akaike's Bayesian Information Criterion (ABIC). The results show that the Yunodake fault started to rupture from the northern deep point 4.5 s after the Itozawa fault started to rupture. The estimated slip distribution in the shallow part is consistent with the surface slip distribution identified by field surveys. Time-dependent Coulomb failure function changes (?CFF) were calculated using the stress change from the Itozawa fault rupture in order to evaluate the effect of the rupture on the Yunodake fault. The ?CFF is positive at the rupture starting point of the Yunodake fault 4.5 s after the Itozawa fault started to rupture; therefore, it is concluded that during the 2011 Hamadori earthquake, the Yunodake fault rupture was triggered by the Itozawa fault rupture.

  7. Spontaneous rupture of multifocal hepatocellular carcinoma: case report

    PubMed Central

    Özen, Özkan; Tosun, Alptekin; Akgül, Çi?dem

    2015-01-01

    Hemoperitoneum due to nontraumatic liver rupture is rare. The most common cause of nontraumatic rupture of the liver is hepatocellular carcinoma (HCC). The other causes of nontraumatic liver ruptures are peliosis hepatis, polyarteritis nodosa, systemic lupus erythematosus, preeclampsia, metastatic carcinoma, and other primary liver tumors. In this report, we present the computed tomography findings of spontaneous liver rupture in a 52-year-old male patient due to multifocal HCC, with the diagnosis proven by surgical specimen. PMID:26316825

  8. Rupture of wetting films caused by nanobubbles.

    PubMed

    Stöckelhuber, Klaus Werner; Radoev, Boryan; Wenger, Andreas; Schulzet, Hans Joachim

    2004-01-01

    It is now widely accepted that nanometer sized bubbles, attached at a hydrophobic silica surface, can cause rupture of aqueous wetting films due to the so-called nucleation mechanism. But the knowledge of the existence of such nanobubbles does not give an answer to how the subprocesses of this rupture mechanism operate. The aim of this paper is to describe the steps of the rupture process in detail: (1) During drainage of the wetting film, the apex of the largest nanobubble comes to a distance from the wetting film surface, where surface forces are acting. (2) An aqueous "foam film" in nanoscale size is formed between the bubble and the wetting film surface; in this foam film different Derjaguin-Landau-Verwey-Overbeek (DLVO) forces are acting than in the surrounding wetting film. In the investigated system, hydrophobized silica/water/air, all DLVO forces in the wetting film are repulsive, whereas in the foam film the van der Waals force becomes attractive. (3) The surface forces over and around the apex of the nanobubble lead to a deformation of the film surfaces, which causes an additional capillary pressure in the foam film. An analysis of the pressure balance in the system shows that this additional capillary pressure can destabilize the foam film and leads to rupture of the foam film. (4) If the newly formed hole in the wetting film has a sufficient diameter, the whole wetting film is destabilized and the solid becomes dewetted. Experimental data of rupture thickness and lifetime of wetting films of pure electrolyte and surfactant solutions show that the stabilization of the foam film by surfactants has a crucial effect on the stability of the wetting film. PMID:15745015

  9. Intracellular amyloid and the neuronal origin of Alzheimer neuritic plaques

    PubMed Central

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

    2014-01-01

    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 10 mo 3XTg-AD mice, indicating that this represents misfolded and aggregated protein rather than normally folded APP. At 12 mo, M78 immunoreactivity also accumulates in the nucleus. Neuritic plaques at 12 mo 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

  10. 6. VIEW OF BRIDGE COMMEMORATIVE PLAQUE WHICH STATES '1908, J. ...

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

    6. VIEW OF BRIDGE COMMEMORATIVE PLAQUE WHICH STATES '1908, J. H. CROOKS, ED. ELLIS, A. S. LELAND, COMMISSIONERS. L. E. BRELSFORD, AUDITOR. L. WEST, SURVEYOR. - B. C. GERWICK, DESIGNER. F. E. WITHCOTT, ENG. ON CONST. C. A. WARNER, CONTRACTOR.' - First Street Reinforced Concrete Bridge, Spanning Moxahala Creek at First Street (CR 7), Roseville, Muskingum County, OH

  11. Ultrasound imaging versus morphopathology in cardiovascular diseases. Coronary atherosclerotic plaque

    PubMed Central

    Baroldi, Giorgio; Bigi, Riccardo; Cortigiani, Lauro

    2004-01-01

    This review article is aimed at comparing the results of histopathological and clinical imaging studies to assess coronary atherosclerotic plaques in humans. In particular, the gap between the two techniques and its effect on the understanding of the pathophysiological basis of coronary artery disease is critically discussed. PMID:15598352

  12. 4. VISTA POINT AND INTERPRETIVE PLAQUE AT LEE VINING CANYON. ...

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

    4. VISTA POINT AND INTERPRETIVE PLAQUE AT LEE VINING CANYON. NOTE ROAD CUT ON CANYON WALL. LOOKING NNE. GIS: N-37 56 30.3 / 119 13 44.8 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

  13. 7. VARIABLEANGLE LAUNCHER DEDICATION PLAQUE SHOWING JAMES H. JENNISON (LEFT), ...

    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

  14. Quantification of plaque neovascularization using contrast ultrasound: a histologic validation

    PubMed Central

    Moguillansky, Diego; Leng, Xiaoping; Carson, Andrew; Lavery, Linda; Schwartz, Abigail; Chen, Xucai; Villanueva, Flordeliza S.

    2011-01-01

    Aims The density of vasa vasorum within atherosclerotic plaque correlates with histologic features of plaque vulnerability in post-mortem studies. Imaging methods to non-invasively detect vasa vasorum are limited. We hypothesized that contrast ultrasound (CUS) can quantify vasa vasorum during atherosclerosis progression. Methods and results New Zealand white rabbits received a high-fat diet for 3 weeks, and bilateral femoral artery stenosis was induced by balloon injury. Contrast ultrasound femoral imaging was performed at baseline and 2, 4, and 6 weeks post injury to quantify adventitial videointensity. At each imaging time point 10 vessels were sectioned and stained with haematoxylin and eosin and von-Willebrand factor. Adventitial vasa vasorum density was quantified by counting the number of stained microvessels and their total cross-sectional area. Plaque size (per cent lumen area) progressed over time (P < 0.001), as did adventitial vasa vasorum density (P < 0.001). Plateau peak videointensity also progressed, demonstrating a strong linear correlation with histologic vasa vasorum density (P < 0.001). Receiver operating characteristic analysis indicated that a three-fold increase in median adventitial videointensity had a sensitivity of 100% and specificity of 88% for predicting abnormal neovascularization. Conclusion We have histologically validated that CUS quantifies the development of adventitial vasa vasorum associated with atherosclerosis progression. This imaging technique has the potential for characterizing prognostically significant plaque features. PMID:20581005

  15. Variogram methods for texture classification of atherosclerotic plaque ultrasound images

    NASA Astrophysics Data System (ADS)

    Jeromin, Oliver M.; Pattichis, Marios S.; Pattichis, Constantinos; Kyriacou, Efthyvoulos; Nicolaides, Andrew

    2006-03-01

    Stroke is the third leading cause of death in the western world and the major cause of disability in adults. The type and stenosis of extracranial carotid artery disease is often responsible for ischemic strokes, transient ischemic attacks (TIAs) or amaurosis fugax (AF). The identification and grading of stenosis can be done using gray scale ultrasound scans. The appearance of B-scan pictures containing various granular structures makes the use of texture analysis techniques suitable for computer assisted tissue characterization purposes. The objective of this study is to investigate the usefulness of variogram analysis in the assessment of ultrasound plague morphology. The variogram estimates the variance of random fields, from arbitrary samples in space. We explore stationary random field models based on the variogram, which can be applied in ultrasound plaque imaging leading to a Computer Aided Diagnosis (CAD) system for the early detection of symptomatic atherosclerotic plaques. Non-parametric tests on the variogram coefficients show that the cofficients coming from symptomatic versus asymptomatic plaques come from distinct distributions. Furthermore, we show significant improvement in class separation, when a log point-transformation is applied to the images, prior to variogram estimation. Model fitting using least squares is explored for anisotropic variograms along specific directions. Comparative classification results, show that variogram coefficients can be used for the early detection of symptomatic cases, and also exhibit the largest class distances between symptomatic and asymptomatic plaque images, as compared to over 60 other texture features, used in the literature.

  16. 10. DETAIL VIEW, LOOKING NORTH, SHOWING COMMEMORATIVE PLAQUE ON EAST ...

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

    10. DETAIL VIEW, LOOKING NORTH, SHOWING COMMEMORATIVE PLAQUE ON EAST SIDE OF SOUTH APPROACH WHICH STATES 'EIGHT MILE CREEK; MILLERS GARAGE & CONT. CO.; CONTRACTOR.; ARKANSAS; STATE HIGHWAY COMMISSION.; DWIGHT H. BLACKWOOD, CHAIRMAN.; C.S. CHRISTIAN, ENGINEER.; 1929.; BRIDGE NO.__' - Eight Mile Creek Bridge, Spanning Eight Mile Creek at U.S. Highway 49, Paragould, Greene County, AR

  17. 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

  18. Development of Tc-99m Imaging Agents for Abeta Plaques

    SciTech Connect

    Zhi-Ping, Zhuang; Mei-Ping Kung; Catherihne Hou; Hank F. Kung

    2008-09-26

    Development of SPECT imaging agents based on Tc-99m targeting Aβ plaques is useful for diagnosis of Alzheimer’s disease (AD). A stilbene derivative, [11C]SB-13, showing promise in detecting senile plaques present in AD patients has been reported previously1,2. Based on the 4’-amino-stilbene core structure we have added substituted groups through which a chelating group, N2S2, was conjugated. We report herein a series of Tc-99m labeled stilbene derivative conjugated with a TcO[N2S2] core. The syntheses of stilbenes containing a N2S2 chelating ligand are achieved by a scheme shown. Lipophilic 99mTc stilbene complexes were successfully prepared and purified through HPLC. Preliminary results of in vitro labeling of brain sections from transgenic mice showed very promising plaque labeling. These 99mTc stilbene derivatives are warranted for further evaluations as potential imaging agents targeting amyloid plaques.

  19. Optical coherence tomography for imaging the vulnerable plaque

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

    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.

  20. Interstellar Message Plaques: Application of White-Light Holography

    NASA Astrophysics Data System (ADS)

    Matloff, G. L.

    2002-01-01

    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.

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

    MedlinePLUS

    ... for a fresh feeling! Rinse again. Remember: Food residues, especially sweets, provide nutrients for the germs that ... why it is important to remove all food residues, as well as plaque, from teeth. Remove plaque ...

  2. Head Injuries Tied to Buildup of Alzheimer's Plaques, Small Study Finds

    MedlinePLUS

    ... 157055.html Head Injuries Tied to Buildup of Alzheimer's Plaques, Small Study Finds But it's too soon ... brain injury may lead to a buildup of Alzheimer's-type plaques in the brain, including in regions ...

  3. In Vivo Diagnosis of Plaque Erosion and Calcified Nodule in Patients with Acute Coronary Syndrome by Intravascular Optical Coherence Tomography

    PubMed Central

    Jia, Haibo; Abtahian, Farhad; Aguirre, Aaron D; Lee, Stephen; Chia, Stanley; Lowe, Harry; Kato, Koji; Yonetsu, Taishi; Vergallo, Rocco; Hu, Sining; Tian, Jinwei; Lee, Hang; Park, Seung-Jung; Jang, Yang-Soo; Raffel, Owen C.; Mizuno, Kyoichi; Uemura, Shiro; Itoh, Tomonori; Kakuta, Tsunekazu; Choi, So-Yeon; Dauerman, Harold L.; Prasad, Abhiram; Toma, Catalin; McNulty, Iris; Zhang, Shaosong; Yu, Bo; Fuster, Valentine; Narula, Jagat; Virmani, Renu; Jang, Ik-Kyung

    2013-01-01

    Objectives To characterize the morphological features of plaque erosion and calcified nodule in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT). Background Plaque erosion and calcified nodule have not been systematically investigated in vivo. Methods One hundred and twenty-six patients with ACS who had undergone pre-intervention OCT imaging were included. The culprit lesions were classified as plaque rupture (PR), erosion (OCT-erosion), calcified nodule (OCT-CN), or others using a new set of diagnostic criteria for OCT. Results The incidences of PR, OCT-erosion, and OCT-CN were 43.7%, 31.0%, and 7.9%, respectively. Patients with OCT-erosion were the youngest compared with those with PR and OCT-CN (53.8±13.1 years vs. 60.6±11.5 years, 65.1±5.0 years, p=0.005). Compared with patients with PR, presentation with non-ST-segment elevation ACS (NSTE-ACS) was more common in patients with OCT-erosion (61.5% vs. 29.1%, p=0.008) and OCT-CN (100% vs. 29.1%, p<0.001). OCT-erosion had a lower frequency of lipid plaque (43.6% vs. 100%, p<0.001), thicker fibrous cap (169.3±99.1 ?m vs. 60.4±16.6 ?m, p<0.001), and smaller lipid arc (202.8±73.6° vs. 275.8±60.4°, p<0.001) than PR. The diameter stenosis was least severe in OCT-erosion followed by OCT-CN and PR (55.4±14.7% vs. 66.1±13.5% vs. 68.8±12.9%, p<0.001). Conclusions OCT is a promising modality for identifying OCT-erosion and OCT-CN in vivo. OCT-erosion is a frequent finding in patients with ACS, especially in those with NSTE-ACS and younger patients. OCT-CN is the least common etiology for ACS and is more common in older patients. PMID:23810884

  4. Laboratory Experiments and Theoretical Studies of Rupture Modes and Supershear Transition

    NASA Astrophysics Data System (ADS)

    Lu, X.; Lapusta, N.; Rosakis, A.

    2007-12-01

    Theoretical studies have shown that the issue of rupture modes has important implications for fault constitutive laws, stress conditions on faults, energy partition and heat generation during earthquakes, scaling laws, and spatio-temporal complexity of fault slip. Early theoretical models often treated earthquakes as crack-like ruptures, but seismic inversions indicate that earthquake ruptures may propagate in a self-healing pulse-like mode. A number of explanations for the existence of slip pulses have been proposed, including strong weakening of the interface with sliding rate, interaction of rupture with local heterogeneities, and normal stress variation due to a bimaterial effect. We observe pulse-like and crack-like rupture modes in the experimental configuration of a Homalite plate with inclined interface prestressed both in compression and in shear, similarly to faults in the Earth's crust. Dynamic rupture is initiated by exploding a 0.1 mm nickel wire. Digital high-speed cameras are used to record photoelastic images. Two interferometry-based velocimeters are used to determine the history of relative sliding velocity at one location along the interface. Our results indicate that pulse-like ruptures can exist on such interfaces in the absence of a bimaterial effect or local heterogeneities. For a set of experiments with increasing ratio of shear to normal prestress, which is achieved by increasing the inclination angle of the interface, we observe a change in rupture modes from pulse-like to crack-like. This systematic variation is consistent with the theoretical study of velocity-weakening interfaces by Zheng and Rice (1998). We also establish experimentally, for the first time, that both pulse-like and crack-like rupture modes can transition to supershear speeds. After the supershear transition, both modes have speeds within the open interval \\sqrt{2} Cs to Cp, where Cs and Cp are the S- and P-wave speeds of Homalite, respectively. However, the rupture speed of pulse-like ruptures is lower. These supershear speeds are consistent with the analytical predictions of the velocity-weakening model of Samudrala et al. (2002). The agreement between our experimental observations and models of velocity-weakening faults suggests that velocity-weakening friction plays an important role in dynamic behavior of ruptures and implies that expressing dynamic weakening of friction solely in terms of slip may not be a sufficiently general description. We will also present our current efforts to further analyze the experiments, including the potential effects of rupture initiation procedure. Our preliminary experimental measurements of vertical motion of points close to the interface indicate that there is no opening of the interface during sliding at locations where we determine the rupture mode, although more analysis is need to determine whether there is any significant normal stress variation. We are in the process of including normal stress variations into our existing numerical code to investigate this issue, as well as to study which friction law is most consistent with the experimental observations. We are also working on quantifying the parameters of the explosion and determining the friction properties of Homalite (collaboration with N. Beeler and B. Kilgore (USGS), C. Marone (Penn State), and G. Ravichandran (Caltech)).

  5. Radionuclide diagnosis of splenic rupture in infectious mononucleosis

    SciTech Connect

    Vezina, W.C.; Nicholson, R.L.; Cohen, P.; Chamberlain, M.J.

    1984-06-01

    Spontaneous splenic rupture is a rare but serious complication of infectious mononucleosis. Although radionuclide spleen imaging is a well accepted method for diagnosis of traumatic rupture, interpretation can be difficult in the setting of mononucleosis, as tears may be ill-defined and diagnosis hampered by inhomogeneous splenic uptake. Four proven cases of spontaneous rupture are presented, three of which illustrate these diagnostic problems.

  6. Ruptured rectal duplication with urogenital abnormality: Unusual presentation

    PubMed Central

    Solanki, Shailesh; Babu, M Narendra; Jadhav, Vinay; Shankar, Gowri; Santhanakrishnan, Ramesh

    2015-01-01

    Rectal duplication (RD) accounts for 5% of alimentary tract duplication. A varied presentation and associated anomalies have been described in the literature. Antenatal rupture of the RD is very rare. We present an unusual case of a ruptured RD associated with urogenital abnormalities in newborn male. We are discussing diagnosis, embryology, management and literature review of ruptured RD. PMID:25552833

  7. Ruptured rectal duplication with urogenital abnormality: Unusual presentation.

    PubMed

    Solanki, Shailesh; Babu, M Narendra; Jadhav, Vinay; Shankar, Gowri; Santhanakrishnan, Ramesh

    2015-01-01

    Rectal duplication (RD) accounts for 5% of alimentary tract duplication. A varied presentation and associated anomalies have been described in the literature. Antenatal rupture of the RD is very rare. We present an unusual case of a ruptured RD associated with urogenital abnormalities in newborn male. We are discussing diagnosis, embryology, management and literature review of ruptured RD. PMID:25552833

  8. Derivative spectrophotometric analysis of cerebrospinal fluid for the detection of a ruptured cerebral aneurysm

    NASA Astrophysics Data System (ADS)

    Bhadri, P. R.; Majumder, A.; Morgan, C. J.; Pyne, G. J.; Zuccarello, M.; Jauch, E.; Wagner, K. R.; Clark, J. F.; Caffery, J., Jr.; Beyette, Fred R., Jr.

    2003-11-01

    A cerebral aneurysm is a weakened portion of an artery in the brain. When a cerebral aneurysm ruptures, a specific type of bleeding known as a subarachnoid hemorrhage (SAH) occurs. No test exists currently to screen people for the presence of an aneurysm. The diagnosis of a SAH is made after an aneurysm ruptures, and the literature indicates that nearly one-third of patients with a SAH are initially misdiagnosed and subjected to the risks associated with aneurysm re-rupture. For those individuals with a suspected SAH, a computerized tomography (CT) scan of the brain usually demonstrates evidence of the bleeding. However, in a considerable portion of people, the CT scan is unable to detect the blood that has escaped from the blood vessel. For circumstances when a SAH is suspected despite a normal CT scan, physicians make the diagnosis of SAH by performing a spinal tap. A spinal tap uses a needle to sample the cerebrospinal fluid (CSF) collected from the patient"s back; CSF is tainted with blood after the aneurysm ruptures. To distinguish between a common headache and a SAH, a fast and an effective solution is required. We describe the development of an effective detection system integrating hardware and a powerful software interface solution. Briefly, CSF from the patient is aspirated and excited with an appropriate wavelength of light. The software employs spectrophotometric analysis of the output spectra and lays the foundation for the development of portable and user-friendly equipment for detection of a ruptured cerebral aneurysm.

  9. Potential rupture surface model and its application on probabilistic seismic hazard analysis

    NASA Astrophysics Data System (ADS)

    Xü, Guang-Yin; Gao, Meng-Tan

    2007-05-01

    Potential sources are simplified as point sources or linear sources in current probabilistic seismic hazard analysis (PSHA) methods. Focus size of large earthquakes is considerable, and fault rupture attitudes may have great influence upon the seismic hazard of a site which is near the source. Under this circumstance, it is unreasonable to use the simplified potential source models in the PSHA, so a potential rupture surface model is proposed in this paper. Adopting this model, we analyze the seismic hazard near the Chelungpu fault that generated the Chi-Chi (Jiji) earthquake with magnitude 7.6 and the following conclusions are reached. ? This model is reasonable on the base of focal mechanism, especially for sites near potential earthquakes with large magnitude; ? The attitudes of potential rupture surfaces have great influence on the results of probabilistic seismic hazard analysis and seismic zoning.

  10. Ruptured Pneumococcal Aortic Aneurysm Presenting as ST-Elevation Myocardial Infarction

    PubMed Central

    Guo, Xiaoyue Mona; Bonde, Pramod

    2015-01-01

    Ruptured mycotic aneurysms occur infrequently in current clinical practice, and a pneumococcal etiology is even more rare. This case report describes a patient who initially presented with catheter lab activation for an acute ST-elevation myocardial infarction, receiving a full Plavix load. She was subsequently found to have a ruptured aortic aneurysm and underwent emergency surgical repair, with intraoperative findings of an aorta seeded with Streptococcus pneumonia. A retrospective evaluation of her history revealed clues of a previous upper respiratory infection and long-standing back pain. The subsequent literature review summarizes presentations and outcomes in previously reported, ruptured pneumococcal aneurysms and describes the relatively common occurrence of aortic conditions masquerading as acute myocardial infarctions. We provide recommendations to help approach similar situations in the future. PMID:26798754

  11. An in vitro biofilm model of subgingival plaque

    PubMed Central

    Walker, C.; Sedlacek, M. J.

    2007-01-01

    Introduction: Numerous biofilm models have been described for the study of bacteria associated with the supragingival plaque. However, there are fewer models available for the study of subgingival plaque. The purpose of this study was to develop and validate a model that closely mimicked the composition of the subgingival flora. Methods: The model was developed as follows: calcium hydroxyapatite disks were coated overnight with 10% sterile saliva, placed in flat-bottomed tissue culture plates containing trypticase-soy broth, directly inoculated with a small aliquot of dispersed subgingival plaque, incubated anaerobically, and transferred to fresh medium at 48-h intervals until climax (steady-state) biofilms were formed (?10 days). Results: The model, based on samples from eight periodontitis patients and eight healthy subjects, yielded a multi-species, heterogeneous biofilm, consisting of both gram-positive and gram-negative species, and comprising 15?20 cultivable species associated with the subgingival flora. The species present and their proportions were reflective of the initial cultivable subgingival flora. Comparisons of the initial plaque samples from healthy subjects and the mature biofilms showed 81% similarity in species and 70% similarity in the proportions present. Biofilms formed from samples obtained from periodontally diseased subjects were 69% similar in species and 57% similar in the proportions present. Conclusions: The biofilm model described here closely reproduces the composition of the cultivable subgingival plaque both in the species present and in their relative proportions. Differences existed between biofilms grown from diseased and non-diseased sites with the former being characterized by the presence of periodontal pathogens at microbially significant levels. PMID:17488440

  12. Relationship between thyroid function and carotid artery plaque ulceration.

    PubMed

    Sevuk, Utkan; Bahadir, Mehmet Veysi; Altindag, Rojhat; Baysal, Erkan; Altintas, Bernas; Yaylak, Baris; Adiyaman, Mehmet Sahin; Ay, Nurettin

    2015-12-01

    Carotid artery plaque ulceration (PU) is known to be associated with cerebrovascular events (CVE). Even within euthyroid ranges, thyroid function has been reported to be associated with carotid atherosclerosis. However, the relationship between thyroid function and carotid PU remains unclear. Our aim was to determine the relationship between thyroid function and PU in patients with internal carotid artery stenosis (ICS). Records of patients with CVE were retrospectively reviewed. A total of 250 consecutive patients with ICS who had computed tomography angiography (CTA) of the carotid arteries following hospitalization were included in the study. CTA was used for the evaluation of carotid artery plaque morphology and ulceration. Plaque morphology was classified as fatty, mixed or calcified. Patients were divided into two groups according to the presence or absence of PU. Subclinical hypothyroidism (SCH) and hypothyroidism were significantly more common in patients with PU (p < 0.001 and p = 0.003, respectively). Patients with PU had higher incidence of low-normal FT4 levels (p = 0.02). Compared with patients who had no PU, patients with PU had decreased FT4 levels and elevated TSH levels (p = 0.001 and p = 0.001, respectively). TSH level (OR 1.33, p = 0.001), SCH (OR 4.2, p = 0.001), hypothyroidism (OR 3.15, p = 0.037), fatty plaque (OR 2.16, p = 0.01) and calcified plaque (OR 0.19, p < 0.001) were independently associated with PU. Our results suggest that SCH and hypothyroidism could be a risk factor for PU and subsequent CVE. Thyroid functions may be useful for risk stratification of patients with ICS. PMID:25672265

  13. Megathrust Properties and Large Earthquake Rupture Processes

    NASA Astrophysics Data System (ADS)

    Lay, T.; Ye, L.; Kanamori, H.

    2014-12-01

    Constraining physical controls on seismic rupture of plate boundary megathrust faults is challenging due to observational limitations, but seismic, geodetic, tsunami, electromagnetic, geologic and hydrologic studies are steadily accumulating data that hold potential of advancing our understanding of subduction fault zones. Very shallow (< 15 km deep) megathrust earthquakes are rare, but intermittently occur as large tsunami earthquakes such as the 2010 Mentawai Mw 7.8 event. This rupture occurred up-dip of prior large interplate ruptures in the Sumatra subduction zone in 2007, and rupture extended all the way to the trench, but with patchy large-slip regions that can only be confidently resolved using tsunami observations. The seismic wave radiation from tsunami earthquakes is now established to be distinct from that of ruptures deeper on the megathrust, but the controlling factors are not well-resolved. Smaller events at shallow depths tend to have diverse rupture processes, but some are also anomalously depleted in short-period radiation, suggesting that the shallow environment has variable scale-lengths of frictional heterogeneity. At the other end of the megathrust, large events deeper than about 35 km tend to have modest enhancement of short-period seismic wave radiation, with somewhat lower slope to their short-period source spectra than typical of shallower events. The controlling process are also not well-resolved for this behavior. These depth-variations of megathrust earthquake source spectra are one class of observations that may relate to pressure- and temperature-dependent evolution of the megathrust from the trench to decoupling depths near 45-50 km. Other attributes of seismic sources, such as static stress drop and moment-scaled radiated energy have large variability, but do not show systematic variations with depth on the megathrust, so some attributes of earthquake processes are not strongly influenced by evolving conditions of the plate boundary. We explore these issues based on a recent seismological study of all large interplate earthquakes from 1990-2014 combined with detailed investigations of several recent large and great earthquakes for which we have unprecedented geophysical data sets.

  14. Isolated Total Rupture of Extraocular Muscles

    PubMed Central

    Chen, Jingchang; Kang, Ying; Deng, Daming; Shen, Tao; Yan, Jianhua

    2015-01-01

    Abstract Total rupture of extraocular muscles is an infrequent clinical finding. Here we conducted this retrospective study to evaluate their causes of injury, clinical features, imaging, surgical management, and final outcomes in cases of isolated extraocular muscle rupture at a tertiary center in China. Thirty-six patients were identified (24 men and 12 women). Mean age was 34 years (range 2–60). The right eye was involved in 21 patients and the left 1 in 15. A sharp object or metal hook was the cause of this lesion in 16 patients, sinus surgery in 14 patients, traffic accident in 3 patients, orbital surgery in 2 patients, and conjunctive tumor surgery in 1 patient. The most commonly involved muscles were medial (18 patients) and inferior rectus muscles (13 patients). The function of the ruptured muscles revealed a scale of ?3 to ?4 defect of ocular motility and the amount of deviation in primary position varied from 10 to 140 PD (prism diopter). Computerized tomography (CT) confirmed the presence of ruptured muscles. An end-to-end muscle anastomosis was performed and 3 to 5?mm of muscle was resected in 23 patients. When the posterior border of the injured muscle could not be identified (13 patients), a partial tendon transposition was performed, together with recession of the antagonist in most patients, whereas a recession of the antagonist muscle plus a resection of the involved muscle with or without nasal periosteal fixation was performed in the remaining patients. After an average of 16.42 months of follow-up an excellent result was achieved in 23 patients and results of 13 patients were considered as a failure. In most patients, the posterior border of the ruptured muscle can be identified and an early surgery can be perform