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Sample records for leaflet perfusion patterns

  1. Local intense mosaic pattern at site of flail mitral leaflet: report of a new color Doppler sign.

    PubMed

    Khouzam, Rami N; D'Cruz, Ivan A; Minderman, Daniel; Kaiser, Jacqueline

    2005-10-01

    Color flow Doppler has been useful in diagnosing the presence and severity of mitral regurgitation (MR). We noted a hitherto unreported sign of MR due to flail mitral leaflet: intense local mosaic pattern at the site of the flail leaflet. This sign was seen well in 11 of 14 patients (79%) with the two-dimensional echocardiographic features of flail mitral leaflet, all with moderate or severe MR. In 3 other patients, the sign was absent; two of those had flail mitral leaflet with severe MR. No local mosaic pattern was seen on color Doppler in 20 other patients with MR but no flail mitral leaflet. We speculate that the focal intense mosaic color Doppler morphology may have been caused by intrusion of the flail leaflet into the MR stream, or to a Coanda-like effect of the MR jet "adhering" to the flail leaflet.

  2. Developmental pattern of the right atrioventricular septal valve leaflet and tendinous cords.

    PubMed

    Guzmán, Laura Villavicencio; Mayoral, Pedro Valencia; Valencia, Julio Páez; Pine, Stanislaw Sadowinski; Gómez, Concepción Sánchez

    2010-01-01

    No consensus exists regarding the precise contribution of myocardium and the atrioventricular (AV) cushion mesenchyme to the development of leaflets, tendinous cords (TCs) and papillary muscles. Furthermore, the origin and fate of the myocardium embedded in the immature mesenchyme of the AV cushions at the beginning of AV valvulogenesis is controversial. Some authors have suggested that these cells result from a mesenchyme-to-myocardium transformation. In contrast, other researchers have concluded that they are derived from the myocardial ventricular wall and the interventricular septum (IVS). On the other hand, it has been assumed that the AV mural and septal leaflets have the same pattern of development. However the supporting structures of the two types of leaflets are anatomically different, which could reflect some differences in the pattern of development. We have therefore investigated the morphogenetic processes involved in sculpting and maturation of the right septal leaflet (RSL) and TCs in embryonic and post-hatching chicken hearts. The origin and fate of the myocardium embedded in the immature cushion mesenchyme at the beginning of RSL morphogenesis was also studied. For this purpose, scanning electron microscopic analysis, histological studies and immunohistochemical detection of Nkx2.5 and MEF2C were performed. Our findings indicate that the RSL and TCs present a distinct morphogenetic pattern from that of the mural leaflets. Our results also provide evidence that myocardial recruitment from the IVS, but not mesenchyme-to-myocardium transformation, participates in the development of the muscular region of the TCs adjacent to the IVS.

  3. Differential firing pattern and response to lighting conditions of rat intergeniculate leaflet neurons projecting to suprachiasmatic nucleus or contralateral intergeniculate leaflet.

    PubMed

    Blasiak, T; Lewandowski, M H

    2013-01-03

    The intergeniculate leaflet (IGL) of the lateral geniculate body in the rat is a population of GABAergic neurons that can be divided into two, anatomically and neurochemically distinct populations. One population comprises neuropeptide-Y (NPY)-positive neurons that form the geniculohypothalamic tract innervating the suprachiasmatic nuclei (SCN) and the other population comprises enkephalin-positive (ENK) neurons giving rise to the geniculo-geniculate tract innervating the contralateral IGL (cIGL). Previous electrophysiological studies have observed various patterns of firing and different responses to changes in lighting conditions of IGL neurons in vitro and in vivo. The aim of the present study was to determine if these distinct properties could be ascribed to differentially projecting IGL neurons. Neuron activity was recorded extracellularly in the IGL of anaesthetised rats under different lighting conditions (i.e. light/dark). Antidromic activation was used to identify recorded cells as projecting to the SCN or the contralateral IGL. All IGL neurons identified as projecting to the contralateral IGL displayed infra-slow oscillatory activity (ISO; i.e. slow rhythmic bursts of action potentials). ISO of these neurons was sustained in the light and was diminished in the darkness. In contrast, all IGL neurons identified as projecting to the SCN displayed a low level of firing in the light and a majority of these cells increased firing in the darkness. All IGL neurons projecting to the SCN were characterised by an irregular pattern of firing in the light and dark. These data are the first to demonstrate that differentially projecting rat intergeniculate leaflet neurons are characterised by distinct firing patterns and opposite responses to light and dark conditions.

  4. Perfusion patterns in migraine with aura.

    PubMed

    Förster, Alex; Wenz, Holger; Kerl, Hans U; Brockmann, Marc A; Groden, Christoph

    2014-10-01

    Migraine with aura is a common neurological disorder, and differentiation from transient ischemic attack or stroke based on clinical symptoms may be difficult. From an MRI report database we identified 33 patients with migraine with aura and compared these to 33 age-matched ischemic stroke patients regarding perfusion patterns on perfusion-weighted imaging (PWI)-derived maps: time to peak (TTP), mean transit time (MTT), and cerebral blood flow and volume (CBF, CBV). In 18/33 (54.5%) patients with migraine with aura, TTP showed areas of hypoperfusion, most of these not limited to the territory of a specific artery but affecting two or more vascular territories. In patients with migraine with aura, TTP (1.09 ± 0.05 vs. 1.47 ± 0.40, p < 0.001) and MTT ratios (1.01 ± 0.10 vs. 1.19 ± 0.21, p = 0.003) were significantly lower compared to patients with ischemic stroke. In contrast to this, CBF and CBV ratios did not differ significantly between both groups. Migraine aura is usually associated with a perfusion deficit not limited to a specific vascular territory, and only a moderate increase of TTP. Thus, hypoperfusion restricted to a single vascular territory in combination with a marked increase of TTP or MTT may be regarded as atypical for migraine aura and suggestive of acute ischemic stroke. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  5. Scintigraphic perfusion patterns in patients with diffuse lung disease

    SciTech Connect

    Newman, G.E.; Sullivan, D.C.; Gottschalk, A.; Putman, C.E.

    1982-04-01

    Perfusion scintigrams of 55 patients with radiographic evidence of diffuse lung disease were reviewed. Thirty-nine had acute and/or chronic changes caused by congestive heart failure, and 16 had diffuse reticulonodular disease. A normal or near-normal perfusion pattern was seen in 40/55 (73%), and this finding was equally common in the two groups. The authors conclude that perfusion scintigraphy is useful in excluding pulmonary embolism in patients with radiographic evidence of diffuse, symmetrical lung disease.

  6. Diel growth patterns of young soybean (Glycine max) leaflets are synchronous throughout different positions on a plant.

    PubMed

    Friedli, Michael; Walter, Achim

    2015-03-01

    Leaf growth is controlled by various internal and external factors. Leaves of dicotyledonous plants show pronounced diel (24 h) growth patterns that are controlled by the circadian clock. To date, it is still uncertain whether diel leaf growth patterns remain constant throughout the development of a plant. In this study, we followed growth from the primary leaves to leaflets of the seventh trifoliate leaf of soybean (Glycine max) on the same plants with a recently developed imaging-based method under controlled conditions and at a high temporal resolution. We found that all leaflets displayed a consistent diel growth pattern with maximum growth towards the end of the night. In some leaves, growth maxima occurred somewhat later - at dawn - as long as the leaves were still in a very early developmental stage. Yet, overall, diel growth patterns of leaves from different positions within the canopy were highly synchronous. Therefore, the diel growth pattern of any leaf at a given point in time is representative for the overall diel growth pattern of the plant leaf canopy and a deviation from the normal diel growth pattern can indicate that the plant is currently facing stress.

  7. Calcium-induced patterns of calcium-oxalate crystals in isolated leaflets of Gleditsia triacanthos L. and Albizia julibrissin Durazz.

    PubMed

    Borchert, R

    1985-08-01

    For experimental induction of crystal cells (=crystal idioblasts) containing calcium-oxalate crystals, the lower epidermis was peeled from seedling leaflets of Gleditsia triacanthos L., exposing the crystal-free mesophyll and minor veins to the experimental solutions on which leaflets were floated for up to 10 d under continous light. On 0.3-2.0 mM Ca-acetate, increasing numbers of crystals, appearing 96 h after peeling, were induced. The pattern of crystal distribution changed with Ca(2+)-concentration ([Ca(2+)]): at low [Ca(2+)], crystals formed only in the non-green bundlesheath cells surrounding the veins, believed to have a relatively low Ca(2+)-extrusion capacity; at higher [Ca(2+)], crystals developed in up to 90% of the mesophyll cells, and at supraoptimal [Ca(2+)], large extracellular crystals formed on the tissue surface. By sequential treatments with solutions of different [Ca(2+)], the following three phases were identified in the induction of crystal cells: (1) during the initial 24-h period (adaptive aging), Ca(2+) is not required and crystal induction is not possible; (2) during the following 48 h (induction period), exposure to 1-2 mM Ca-acetate induces the differentiation of mesophyll cells into crystal cells; (3) crystal growth begins 72 h after the start of induction. In intact leaflets of Albizia julibrissin Durazz., calcium-oxalate crystals are found exclusively in the bundle-sheath cells of the veins, but crystals were induced in the mesophyll of peeled leaflets floating on 1 mM Ca-acetate. Exposure to inductive [Ca(2+)] will thus trigger the differentiation of mature leaf cells into crystal cells; the spatial distribution of crystals is determined by the external [Ca(2+)] and by the structural and functional properties of the cells in the tissue.

  8. Opening-closing pattern of four pericardial prostheses: results from an in vitro study of leaflet kinematics.

    PubMed

    Tasca, Giordano; Fiore, Gianfranco Beniamino; Mangini, Andrea; Romagnoni, Claudia; Gamba, Amando; Redaelli, Alberto; Antona, Carlo; Vismara, Riccardo

    2016-12-01

    Pericardial and porcine stented aortic valves have different leaflet kinematics. To study the biomechanics of a prosthesis thoroughly, the in vitro setting is the most appropriate. The aim of our study was to find out whether the prosthesis design in which the pericardial sheet is outside the stent post might influence the opening and closing patterns of the leaflets. Four pericardial prostheses (Magna Ease [MG] 21, Trifecta [TRI] 21, Soprano-Armonia [SA] 20 and Mitroflow [MF] 23) that fitted aortic roots with a native annulus diameter of 2.1 cm were implanted and their leaflet kinematics was studied by a high-speed digital camera. In the opening phase, MG showed the shortest RVOT and the highest RVOVI, with values of 12 ± 2 and 209 ± 17 ms, respectively. The RVOT of MG was significantly shorter than that of MF (p < 0.01), but not than that of TRI (p = 0.286). Both TRI and SA showed similar opening patterns (TRI: RVOT of 15 ± 3 ms and RVOVI of 132 ± 25 ms; SA: 17 ± 2 ms and 126 ± 19 ms), without statistically significant difference. Conversely, MF showed the slowest profile, with an RVOT of 23 ± 3 ms and an RVOVI of 94 ± 8 ms (Table 1; Fig. 3). The opening/closing profile is not influenced by the position of the pericardial leaflets, but depends on other intrinsic structural characteristics related to the material used for the stent and leaflets. Moreover, the kinematics does not affect the valve performance. Table 1 Kinematics and hydrodynamic results, reported as means and standard deviations, evaluated over the tested heart samples TRI SA MG MF ANOVA TRI versus SA TRI versus MG TRI versus MF SA versus MG SA versus MF MG versus MF p Value p Value p Value p Value p Value p Value p Value ET (ms) 1.0 1.0 1.0 1.0 RVOT (ms) 15 ± 3 17 ± 2 12 ± 2 23 ± 3 <0.01 1.0 0.286 <0.01 0.03 <0.01 <0.01 SVCT (ms) 247 ± 14 231 ± 15 256 ± 26 241 ± 11 0.170 0.463 0.853 0.931 0.213 1.0 1.0 RVCT (ms) 35 ± 19 52 ± 13 32

  9. Heart failure diagnostics based on ventilation/perfusion single photon emission computed tomography pattern and quantitative perfusion gradients.

    PubMed

    Jögi, Jonas; Palmer, John; Jonson, Björn; Bajc, Marika

    2008-08-01

    Left heart failure (LHF) is a common and frequently overlooked condition owing to insufficient diagnostic methods. This can potentially delay onset of treatment. Our clinical experience with ventilation/perfusion single photon emission computed tomography (V/P SPECT) indicates that perfusion shows an antigravitational distribution pattern in LHF. The aim of the study was to test the hypothesis that LHF diagnosis can be made on the basis of V/P SPECT, and to develop and perform a first evaluation of objective parameters for LHF diagnostics in terms of perfusion gradients. This retrospective study included 247 consecutive patients with clinical suspicion of pulmonary embolism (PE), who were examined with V/P SPECT. Perfusion gradients were developed and quantified in dorso-ventral and cranio-caudal directions. Quantitative results were compared with visual interpretation of patients with normal and heart failure patterns. Patients with LHF pattern were retrospectively followed up by review of medical records to confirm or discard heart failure diagnosis at the time of V/P SPECT examination. LHF pattern on V/P SPECT was identified in 36 patients (15%), normal ventilation/perfusion pattern was found in 67 patients (27%), and PE in 62 patients (25%). The follow-up confirmed heart failure diagnosis in 32 of the 36 cases with LHF pattern, leading to a positive predictive value of 88% for LHF diagnosis based on V/P SPECT. Dorso-ventral perfusion gradients discriminated normal from LHF patients. In patients with suspected PE, LHF is common. Appropriate V/P SPECT pattern recognition, supported by objectively determined dorso-ventral perfusion gradients, allows the diagnosis of LHF. A positive perfusion gradient in the dorso-ventral direction should lead to consideration of heart failure as a possible explanation for the symptoms in these patients.

  10. Regional ventilation/perfusion mismatch pattern in patient with Swyer James (MacLeod's) syndrome.

    PubMed

    Sager, Sait; Asa, Sertac; Akyel, Reşit; Atahan, Ersan; Kanmaz, Bedii

    2014-09-01

    Swyer James (McLeod's) syndrome (SJMS) is an uncommon disease, which occurs as a result of childhood bronchiolitis obliterans. Patients may not be diagnosed until later in their life. A 46-year-old man underwent ventilation/perfusion scintigraphy for acute onset of dyspnea. The scan showed markedly diminished ventilation and perfusion unilaterally on the right middle and inferior lobes. However, mismatched ventilation-perfusion pattern was shown on the upper right lobe, which was consistent with pulmonary embolism. Unilaterally matched ventilation/perfusion defect can see in SJMS in lung scintigraphy; however, when pulmoner embolism may accompany, scintigraphy should be carefully examined.

  11. Regional ventilation/perfusion mismatch pattern in patient with Swyer James (MacLeod's) syndrome

    PubMed Central

    Sager, Sait; Asa, Sertac; Akyel, Reşit; Atahan, Ersan; Kanmaz, Bedii

    2014-01-01

    Swyer James (McLeod's) syndrome (SJMS) is an uncommon disease, which occurs as a result of childhood bronchiolitis obliterans. Patients may not be diagnosed until later in their life. A 46-year-old man underwent ventilation/perfusion scintigraphy for acute onset of dyspnea. The scan showed markedly diminished ventilation and perfusion unilaterally on the right middle and inferior lobes. However, mismatched ventilation-perfusion pattern was shown on the upper right lobe, which was consistent with pulmonary embolism. Unilaterally matched ventilation/perfusion defect can see in SJMS in lung scintigraphy; however, when pulmoner embolism may accompany, scintigraphy should be carefully examined. PMID:25535507

  12. Motility patterns of ex vivo intestine segments depend on perfusion mode.

    PubMed

    Schreiber, Dominik; Jost, Viktor; Bischof, Michael; Seebach, Kristina; Lammers, Wim Jep; Douglas, Rees; Schäfer, Karl-Herbert

    2014-12-28

    To evaluate and characterize motility patterns from small intestinal gut segments depending on different perfusion media and pressures. Experiments were carried out in a custom designed perfusion chamber system to validate and standardise the perfusion technique used. The perfusion chamber was built with a transparent front wall allowing for optical motility recordings and a custom made fastener to hold the intestinal segments. Experiments with different perfusion and storage media combined with different luminal pressures were carried out to evaluate the effects on rat small intestine motility. Software tools which enable the visualization and characterization of intestinal motility in response to different stimuli were used to evaluate the videotaped experiments. The data collected was presented in so called heatmaps thus providing a concise overview of form and strength of contractility patterns. Furthermore, the effect of different storage media on tissue quality was evaluated. Haematoxylin-Eosin stainings were used to compare tissue quality depending on storage and perfusion mode. Intestinal motility is characterized by different repetitive motility patterns, depending on the actual situation of the gut. Different motility patterns could be recorded and characterized depending on the perfusion pressure and media used. We were able to describe at least three different repetitive patterns of intestinal motility in vitro. Patterns with an oral, anal and oro-anal propagation direction could be recorded. Each type of pattern finalized its movement with or without a subsequent distension of the wavefront. Motility patterns could clearly be distinguished in heatmap diagrams. Furthermore undirected motility could be observed. The quantity of the different patterns varies and is highly dependent on the perfusion medium used. Tissue preservation varies depending on the perfusion medium utilized, therefore media with a simple composition as Tyrode solution can only be

  13. Motility patterns of ex vivo intestine segments depend on perfusion mode

    PubMed Central

    Schreiber, Dominik; Jost, Viktor; Bischof, Michael; Seebach, Kristina; Lammers, Wim JEP; Douglas, Rees; Schäfer, Karl-Herbert

    2014-01-01

    AIM: To evaluate and characterize motility patterns from small intestinal gut segments depending on different perfusion media and pressures. METHODS: Experiments were carried out in a custom designed perfusion chamber system to validate and standardise the perfusion technique used. The perfusion chamber was built with a transparent front wall allowing for optical motility recordings and a custom made fastener to hold the intestinal segments. Experiments with different perfusion and storage media combined with different luminal pressures were carried out to evaluate the effects on rat small intestine motility. Software tools which enable the visualization and characterization of intestinal motility in response to different stimuli were used to evaluate the videotaped experiments. The data collected was presented in so called heatmaps thus providing a concise overview of form and strength of contractility patterns. Furthermore, the effect of different storage media on tissue quality was evaluated. Haematoxylin-Eosin stainings were used to compare tissue quality depending on storage and perfusion mode. RESULTS: Intestinal motility is characterized by different repetitive motility patterns, depending on the actual situation of the gut. Different motility patterns could be recorded and characterized depending on the perfusion pressure and media used. We were able to describe at least three different repetitive patterns of intestinal motility in vitro. Patterns with an oral, anal and oro-anal propagation direction could be recorded. Each type of pattern finalized its movement with or without a subsequent distension of the wavefront. Motility patterns could clearly be distinguished in heatmap diagrams. Furthermore undirected motility could be observed. The quantity of the different patterns varies and is highly dependent on the perfusion medium used. Tissue preservation varies depending on the perfusion medium utilized, therefore media with a simple composition as Tyrode

  14. Distinct cerebral perfusion patterns in FTLD and AD

    PubMed Central

    Hu, W.T.; Wang, Z.; Lee, V.M.-Y.; Trojanowski, J.Q.; Detre, J.A.; Grossman, M.

    2010-01-01

    Objective: We examined the utility of distinguishing between patients with frontotemporal lobar degeneration (FTLD) and Alzheimer disease (AD) using quantitative cerebral blood flow (CBF) imaging with arterial spin labeled (ASL) perfusion MRI. Methods: Forty-two patients with FTLD and 18 patients with AD, defined by autopsy or CSF-derived biomarkers for AD, and 23 matched controls were imaged with a continuous ASL method to quantify CBF maps covering the entire brain. Results: Patients with FTLD and AD showed distinct patterns of hypoperfusion and hyperperfusion. Compared with controls, patients with FTLD showed significant hypoperfusion in regions of the frontal lobe bilaterally, and hyperperfusion in posterior cingulate and medial parietal/precuneus regions. Compared with controls, patients with AD showed significant hypoperfusion in the medial parietal/precuneus and lateral parietal cortex, and hyperperfusion in regions of the frontal lobe. Direct comparison of patient groups showed significant inferior, medial, and dorsolateral frontal hypoperfusion in FTLD, and significant hypoperfusion in bilateral lateral temporal-parietal and medial parietal/precuneus regions in AD. Conclusions: Doubly dissociated areas of hypoperfusion in FTLD and AD are consistent with areas of significant histopathologic burden in these groups. ASL is a potentially useful biomarker for distinguishing patients with these neurodegenerative diseases. GLOSSARY Aβ42 = β-amyloid1-42; AD = Alzheimer disease; ASL = arterial spin labeling; bvFTD = behavioral-variant frontotemporal dementia; cASL = continuous arterial spin labeling; CBS = corticobasal syndrome; CBF = cerebral blood flow; dACC = dorsal anterior cingulate cortex; dlPFC = dorsolateral prefrontal cortex; FDR = false detection rate; FTLD = frontotemporal lobar degeneration; GM = gray matter; iFC = inferior frontal cortex; MCI = mild cognitive impairment; MNI = Montreal Neurological Institute; mTC = middle temporal cortex; OFC

  15. Arterial spin labelling reveals an abnormal cerebral perfusion pattern in Parkinson’s disease

    PubMed Central

    Watts, Richard; MacAskill, Michael R.; Pearson, John F.; Rüeger, Sina; Pitcher, Toni L.; Livingston, Leslie; Graham, Charlotte; Keenan, Ross; Shankaranarayanan, Ajit; Alsop, David C.; Dalrymple-Alford, John C.; Anderson, Tim J.

    2011-01-01

    There is a need for objective imaging markers of Parkinson’s disease status and progression. Positron emission tomography and single photon emission computed tomography studies have suggested patterns of abnormal cerebral perfusion in Parkinson’s disease as potential functional biomarkers. This study aimed to identify an arterial spin labelling magnetic resonance-derived perfusion network as an accessible, non-invasive alternative. We used pseudo-continuous arterial spin labelling to measure cerebral grey matter perfusion in 61 subjects with Parkinson’s disease with a range of motor and cognitive impairment, including patients with dementia and 29 age- and sex-matched controls. Principal component analysis was used to derive a Parkinson’s disease-related perfusion network via logistic regression. Region of interest analysis of absolute perfusion values revealed that the Parkinson’s disease pattern was characterized by decreased perfusion in posterior parieto-occipital cortex, precuneus and cuneus, and middle frontal gyri compared with healthy controls. Perfusion was preserved in globus pallidus, putamen, anterior cingulate and post- and pre-central gyri. Both motor and cognitive statuses were significant factors related to network score. A network approach, supported by arterial spin labelling-derived absolute perfusion values may provide a readily accessible neuroimaging method to characterize and track progression of both motor and cognitive status in Parkinson’s disease. PMID:21310726

  16. Pattern of brain blood perfusion in tinnitus patients using technetium-99m SPECT imaging

    PubMed Central

    Mahmoudian, Saeid; Farhadi, Mohammad; Gholami, Saeid; Saddadi, Fariba; Karimian, Ali Reza; Mirzaei, Mohammad; Ghoreyshi, Esmaeel; Ahmadizadeh, Majid; Lenarz, Thomas

    2012-01-01

    Background and Purpose: Tinnitus is associated with an increased activity in central auditory system as demonstrated by neuroimaging studies. Brain perfusion scanning using single photon emission computed tomography (SPECT) was done to understand the pattern of brain blood perfusion of tinnitus subjects and find the areas which are mostly abnormal in these patients. Materials and Methods: A number of 122 patients with tinnitus were enrolled to this cross-sectional study. They underwent SPECT and magnetic resonance imaging (MRI) of brain, and the images were fused to find the regions with abnormal perfusion. Results: SPECT scan results were abnormal in 101 patients (83%). Most patients had bilateral abnormal perfusion (N = 65, 53.3%), and most subjects had abnormality in middle-temporal gyrus (N = 83, 68%) and temporoparietal cortex (N = 46, 37.7%). Patients with multifocal involvement had the least mean age than other 2 groups (patients with no abnormality and unifocal abnormality) (P value = 0.045). Conclusions: Brain blood perfusion pattern differs in patient with tinnitus than others. These patients have brain perfusion abnormality, mostly in auditory gyrus (middle temporal) and associative cortex (temporoparietal cortex). Multifocal abnormalities might be due to more cognitive and emotional brain centers involvement due to tinnitus or more stress and anxiety of tinnitus in the young patients. PMID:23267375

  17. Parkinson's disease-related perfusion and glucose metabolic brain patterns identified with PCASL-MRI and FDG-PET imaging.

    PubMed

    Teune, Laura K; Renken, Remco J; de Jong, Bauke M; Willemsen, Antoon T; van Osch, Matthias J; Roerdink, Jos B T M; Dierckx, Rudi A; Leenders, Klaus L

    2014-01-01

    Under normal conditions, the spatial distribution of resting cerebral blood flow and cerebral metabolic rate of glucose are closely related. A relatively new magnetic resonance (MR) technique, pseudo-continuous arterial spin labeling (PCASL), can be used to measure regional brain perfusion. We identified a Parkinson's disease (PD)-related perfusion and metabolic covariance pattern in the same patients using PCASL and FDG-PET imaging and assessed (dis)similarities in the disease-related pattern between perfusion and metabolism in PD patients. Nineteen PD patients and seventeen healthy controls underwent [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Of 14 PD patients and all healthy controls PCASL-MRI could be obtained. Data were analyzed using scaled subprofile model/principal component analysis (SSM/PCA). Unique Parkinson's disease-related perfusion and metabolic covariance patterns were identified using PCASL and FDG-PET in the same patients. The PD-related metabolic covariance brain pattern is in high accordance with previously reports. Also our disease-related perfusion pattern is comparable to the earlier described perfusion pattern. The most marked difference between our perfusion and metabolic patterns is the larger perfusion decrease in cortical regions including the insula. We identified PD-related perfusion and metabolic brain patterns using PCASL and FDG-PET in the same patients which were comparable with results of existing research. In this respect, PCASL appears to be a promising addition in the early diagnosis of individual parkinsonian patients.

  18. Parkinson's disease-related perfusion and glucose metabolic brain patterns identified with PCASL-MRI and FDG-PET imaging

    PubMed Central

    Teune, Laura K.; Renken, Remco J.; de Jong, Bauke M.; Willemsen, Antoon T.; van Osch, Matthias J.; Roerdink, Jos B.T.M.; Dierckx, Rudi A.; Leenders, Klaus L.

    2014-01-01

    Introduction Under normal conditions, the spatial distribution of resting cerebral blood flow and cerebral metabolic rate of glucose are closely related. A relatively new magnetic resonance (MR) technique, pseudo-continuous arterial spin labeling (PCASL), can be used to measure regional brain perfusion. We identified a Parkinson's disease (PD)-related perfusion and metabolic covariance pattern in the same patients using PCASL and FDG-PET imaging and assessed (dis)similarities in the disease-related pattern between perfusion and metabolism in PD patients. Methods Nineteen PD patients and seventeen healthy controls underwent [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Of 14 PD patients and all healthy controls PCASL-MRI could be obtained. Data were analyzed using scaled subprofile model/principal component analysis (SSM/PCA). Results Unique Parkinson's disease-related perfusion and metabolic covariance patterns were identified using PCASL and FDG-PET in the same patients. The PD-related metabolic covariance brain pattern is in high accordance with previously reports. Also our disease-related perfusion pattern is comparable to the earlier described perfusion pattern. The most marked difference between our perfusion and metabolic patterns is the larger perfusion decrease in cortical regions including the insula. Conclusion We identified PD-related perfusion and metabolic brain patterns using PCASL and FDG-PET in the same patients which were comparable with results of existing research. In this respect, PCASL appears to be a promising addition in the early diagnosis of individual parkinsonian patients. PMID:25068113

  19. Perfusion-CT of Developmental Venous Anomalies: Typical and Atypical Hemodynamic Patterns

    PubMed Central

    Kroll, Hannes; Soares, Bruno P.; Saloner, David; Dillon, William P.; Wintermark, Max

    2009-01-01

    Summary This article reports perfusion-CT patterns that can be observed in patients with DVAs. In atypical DVAs, an abnormal venous congestion pattern with increased CBV, CBF and MTT can be observed in the vicinity of a DVA, and needs to be recognized and differentiated from other entities such as cerebral neoplasms or stroke. This pattern might help to stratify risks of associated complications such as hemorrhage. PMID:19959233

  20. LEAFLETS ON HISTORICAL LINGUISTICS.

    ERIC Educational Resources Information Center

    National Council of Teachers of English, Champaign, IL.

    THIS PORTFOLIO, PREPARED BY THE NATIONAL COUNCIL OF TEACHERS OF ENGLISH COMMISSION ON THE ENGLISH LANGUAGE, CONTAINS SIX LEAFLETS ON LITERARY WORKS SIGNIFICANT TO THE HISTORY OF THE ENGLISH LANGUAGE--(1) "BEOWULF," (2) "THE PETERBOROUGH CHRONICLE," (3) "CANTERBURY TALES," (4) WILLIAM CAXTON'S "PROLOGUE TO THE BOKE OF ENEYDOS," (5) SECOND QUARTO OF…

  1. LEAFLETS ON HISTORICAL LINGUISTICS.

    ERIC Educational Resources Information Center

    National Council of Teachers of English, Champaign, IL.

    THIS PORTFOLIO, PREPARED BY THE NATIONAL COUNCIL OF TEACHERS OF ENGLISH COMMISSION ON THE ENGLISH LANGUAGE, CONTAINS SIX LEAFLETS ON LITERARY WORKS SIGNIFICANT TO THE HISTORY OF THE ENGLISH LANGUAGE--(1) "BEOWULF," (2) "THE PETERBOROUGH CHRONICLE," (3) "CANTERBURY TALES," (4) WILLIAM CAXTON'S "PROLOGUE TO THE BOKE OF ENEYDOS," (5) SECOND QUARTO OF…

  2. ASSOCIATION BETWEEN RETINAL HEMORRHAGIC PATTERNS AND PERFUSION STATUS IN EYES WITH ACUTE CENTRAL RETINAL VEIN OCCLUSION.

    PubMed

    Muraoka, Yuki; Uji, Akihito; Tsujikawa, Akitaka; Murakami, Tomoaki; Ooto, Sotaro; Suzuma, Kiyoshi; Takahashi, Ayako; Iida, Yuto; Miwa, Yuko; Hata, Masayuki; Yoshimura, Nagahisa

    2017-03-01

    To evaluate peripheral retinal hemorrhagic patterns in eyes with acute central retinal vein occlusion, and to explore their clinical relevance in differentiating for the retinal perfusion status, through a prospective, and cross-sectional study. Fifty eyes with acute central retinal vein occlusion were included. Retinal hemorrhagic patterns at the equator and retinal perfusion status were evaluated by ultra-wide field fundus photography and fluorescein angiography. Retinal perfusion was categorized as nonischemic in 29 eyes, ischemic in 18 eyes, and undeterminable in 3 eyes. None of the examined eyes had flame-shaped retinal hemorrhages in the periphery. All hemorrhages were rounded-dot or blot and were variable in size. Particle analysis was performed to quantify hemorrhage size, and showed higher values in eyes having larger blot hemorrhages, and lower values in eyes having dot or smaller blot hemorrhages. Mean size of maximum peripheral dot or blot hemorrhage was larger in eyes classified as ischemic (10,763.0 ± 5,946.3 pixels) than as nonischemic (2,839.9 ± 1,153.6 pixels, P < 0.001). The authors calculated area under the curve to investigate the ability of continuous variables to discriminate retinal perfusion status, which was 0.963 (P < 0.001) for mean size of maximum peripheral blot hemorrhages. The authors objectively evaluated retinal hemorrhagic patterns at the equator in eyes with acute central retinal vein occlusion using particle analysis. The resulting hemorrhage size measurement was considered to be often useful in determining retinal perfusion status. Because they can be noninvasively evaluated with readily available equipment, peripheral hemorrhagic patterns might be good clinical markers of retinal perfusion.

  3. Patterns of pulmonary perfusion scans in normal subjects

    SciTech Connect

    Wallace, J.M.; Moser, K.M.; Hartman, M.T.; Ashburn, W.L.

    1981-01-01

    A vital factor conditioning the usage of the pulmonary perfusion (Q) scan in the evaluation of patients suspected of pulmonary embolism is the prevalence of abnormal Q scans in subjects free of cardiopulmonary disease. Because this prevalence has not been well defined, we performed Q scans in 80 nonsmoking subjects 18 to 29 yr of age having no known active cardiopulmonary disease. Each subject underwent a history, physical examination, electrocardiogram, spirometry, and PA chest roentgenogram, followed by a 6-view Q scan. Two subjects in whom a Q defect was suspected underwent a /sup 133/Xe equilibrium-washout ventilation (V) scan. All Q scans were interpreted blindly and independently by 2 experienced readers. Seventy-nine of the 80 Q scans were read as normal. No subject demonstrated a lobar or segmental defect. One of the 80 subjects, who had a mild pectus excavatum, had a left upper lobe subsegmental defect, which was not seen on the V scan. Based on the statistical analysis of these data, no more than 3.68% of normal nonsmoking persons in this age group may have a lobar or segmental Q scan defect and no more than 6.77% may have a subsegmental defect (with 95% confidence). Therefore, our study indicated that Q scan defects, particularly lobar or segmental, are rarely present among normal nonsmokers in this age group.

  4. Specific cerebral perfusion patterns in three schizophrenia symptom dimensions.

    PubMed

    Stegmayer, Katharina; Strik, Werner; Federspiel, Andrea; Wiest, Roland; Bohlhalter, Stephan; Walther, Sebastian

    2017-03-17

    Dimensional concepts such as the Research Domain Criteria initiative have been proposed to disentangle the heterogeneity of schizophrenia. One model introduced three neurobiologically informed behavioral dimensions: language, affectivity and motor behavior. To study the brain-behavior associations of these three dimensions, we investigated whether current behavioral alterations were linked to resting state perfusion in distinct brain circuits in schizophrenia. In total, 47 patients with schizophrenia spectrum disorders and 44 healthy controls were included. Psychopathology was assessed with the Positive And Negative Syndrome Scale and the Bern Psychopathology scale (BPS). The BPS provides severity ratings of three behavioral dimensions (language, affectivity and motor). Patients were classified according to the severity of alterations (severe, mild, no) in each dimension. Whole brain resting state cerebral blood flow (CBF) was compared between patient subgroups and controls. Two symptom dimensions were associated with distinct CBF changes. Behavioral alterations in the language dimension were linked to increased CBF in Heschl's gyrus. Altered affectivity was related to increased CBF in amygdala. The ratings of motor behavior instead were not specifically associated with CBF. Investigating behavioral alterations in three schizophrenia symptom dimensions identified distinct regional CBF changes in the language and limbic brain circuits. The results demonstrate a hitherto unknown segregation of pathophysiological pathways underlying a limited number of specific symptom dimensions in schizophrenia. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Coronary Flow Impacts Aortic Leaflet Mechanics and Aortic Sinus Hemodynamics.

    PubMed

    Moore, Brandon L; Dasi, Lakshmi Prasad

    2015-09-01

    Mechanical stresses on aortic valve leaflets are well-known mediators for initiating processes leading to calcific aortic valve disease. Given that non-coronary leaflets calcify first, it may be hypothesized that coronary flow originating from the ostia significantly influences aortic leaflet mechanics and sinus hemodynamics. High resolution time-resolved particle image velocimetry (PIV) measurements were conducted to map the spatiotemporal characteristics of aortic sinus blood flow and leaflet motion with and without physiological coronary flow in a well-controlled in vitro setup. The in vitro setup consists of a porcine aortic valve mounted in a physiological aorta sinus chamber with dynamically controlled coronary resistance to emulate physiological coronary flow. Results were analyzed using qualitative streak plots illustrating the spatiotemporal complexity of blood flow patterns, and quantitative velocity vector and shear stress contour plots to show differences in the mechanical environments between the coronary and non-coronary sinuses. It is shown that the presence of coronary flow pulls the classical sinus vorticity deeper into the sinus and increases flow velocity near the leaflet base. This creates a beneficial increase in shear stress and washout near the leaflet that is not seen in the non-coronary sinus. Further, leaflet opens approximately 10% farther into the sinus with coronary flow case indicating superior valve opening area. The presence of coronary flow significantly improves leaflet mechanics and sinus hemodynamics in a manner that would reduce low wall shear stress conditions while improving washout at the base of the leaflet.

  6. Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris

    SciTech Connect

    Selwyn, A.P.; Forse, G.; Fox, K.; Jonathan, A.; Steiner, R.

    1981-07-01

    Fifty patients who presented with angina pectoris were studied to examine the disturbances of regional myocardial perfusion during stress. Each patient underwent 16-point precordial mapping of the ECG during an exercise test, and coronary and left ventricular angiography. Regional myocardial perfusion was assessed using an atrial pacing test and a short-lived radionuclide, krypton-81m. Eleven patients had negative exercise tests and uniform increases in myocardial activity of krypton-81m of 98 +/- 18.0% during pacing. Ten patients performed 30,000-43,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and increases in myocardial activity of krypton-81m to remote and jeopardized myocardium at the onset of pacing. However, further pacing produced a decrease in activity in the affected segment of 68.0 +/- 9.0% accompanied by ST-segment depression and angina. Twelve patients achieved 26,000-32,000 J in positive exercise tests and had significant coronary artery disease. Atrial pacing produced increased activity of krypton-81m to remote myocardium. The jeopardized segment at first showed no change and then a decrease in regional activity of krypton-81m (89.0 +/- 17%) accompanied by ST-segment depression and chest pain. Seventeen patients achieved only 7000-22,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and developed decreases in regional activity of krypton-81m to the affected segment of myocardium starting at the onset of atrial pacing and decreasing by 88 +/- 0 7.0% below control. We conclude that different patterns of disturbed myocardial distribution of krypton-81m are present during stress-induced ischemia in patients with coronary artery disease. There was a close temporal relationship between these disturbances and ST-segment depression.

  7. Bilateral basal Xe-133 retention and ventilation/perfusion patterns in mild and subclinical congestive heart failure

    SciTech Connect

    Lee, H.K.; Skarzynski, J.J.; Spadaro, A. )

    1989-12-01

    The Xe-133 ventilation pattern in congestive heart failure (CHF) was assessed using 24 inpatient ventilation/perfusion studies performed to rule out pulmonary embolism. Patients with histories of CHF, myocardial infarction (MI), and cardiomyopathy were included in the study. Frank pulmonary edema, pulmonary embolism, and other known lung diseases such as chronic obstructive lung disease, tumor, and pneumonia were excluded. Fifteen of the 24 patients had abnormal ventilation scans. Twelve of the 15 showed bilateral basal Xe-133 retention on washout; the remaining 3 showed diffuse, posterior regional retention. On perfusion scans, 14 of the 15 abnormal ventilation patients showed evidence of CHF such as inverted perfusion gradient, enlarged cardiac silhouette, or patchy perfusion, and all of them had a history of CHF or cardiac disease. Nine of the 24 patients had normal ventilation scans, including normal washout patterns. Seven of the nine had normal perfusion (p less than 0.01). Four of the nine normal ventilation patients had a history of cardiac disease or CHF but no recent acute MI. Bilateral basal regional Xe-133 retention, coupled with perfusion scan evidence of CHF such as inverted perfusion gradient, enlarged cardiac silhouette, and patchy perfusion pattern, appears to be a sensitive and characteristic ventilation/perfusion finding in mild or subclinical CHF.

  8. Sleep Deprivation Reveals Altered Brain Perfusion Patterns in Somnambulism

    PubMed Central

    Dang-Vu, Thien Thanh; Zadra, Antonio; Labelle, Marc-Antoine; Petit, Dominique; Soucy, Jean-Paul; Montplaisir, Jacques

    2015-01-01

    Background Despite its high prevalence, relatively little is known about the pathophysiology of somnambulism. Increasing evidence indicates that somnambulism is associated with functional abnormalities during wakefulness and that sleep deprivation constitutes an important drive that facilitates sleepwalking in predisposed patients. Here, we studied the neural mechanisms associated with somnambulism using Single Photon Emission Computed Tomography (SPECT) with 99mTc-Ethylene Cysteinate Dimer (ECD), during wakefulness and after sleep deprivation. Methods Ten adult sleepwalkers and twelve controls with normal sleep were scanned using 99mTc-ECD SPECT in morning wakefulness after a full night of sleep. Eight of the sleepwalkers and nine of the controls were also scanned during wakefulness after a night of total sleep deprivation. Between-group comparisons of regional cerebral blood flow (rCBF) were performed to characterize brain activity patterns during wakefulness in sleepwalkers. Results During wakefulness following a night of total sleep deprivation, rCBF was decreased bilaterally in the inferior temporal gyrus in sleepwalkers compared to controls. Conclusions Functional neural abnormalities can be observed during wakefulness in somnambulism, particularly after sleep deprivation and in the inferior temporal cortex. Sleep deprivation thus not only facilitates the occurrence of sleepwalking episodes, but also uncovers patterns of neural dysfunction that characterize sleepwalkers during wakefulness. PMID:26241047

  9. Assessment of the myocardial perfusion pattern in patients with multivessel coronary artery disease

    SciTech Connect

    Iskandrian, A.S.; Hakki, A.H.; Segal, B.L.; Kane, S.A.; Amenta, A.

    1983-11-01

    A total of 42 symptomatic patients with coronary artery disease involving two or three vessels were studied using exercise thallium-201 myocardial scintigraphy. Qualitative analysis of the images predicted multivessel disease in 75% of the patients with two-vessel disease and in 82% of the patients with three-vessel disease. Quantitative analysis of the size of the perfusion defect indicated that approximately 40% of the left ventricular perimeter showed abnormal perfusion pattern during stress in these patients, and there was no significant difference in the size of the defect in patients with two-vessel disease or three-vessel disease (41 +/- 17% vs 42 +/- 14%, respectively, mean +/- SD). The exercise heart rate, exercise ECG response, and severity of narrowing did not correlate with the size of the perfusion defect. Patients with anterior infarction had larger defects in the distribution of the left anterior descending artery than those without infarction. Collaterals offered partial protection during exercise only when they were not jeopardized. This study confirms the value of qualitative analysis of exercise thallium-201 imaging in predicting multivessel disease, and describes a simple method of assessing the extent of perfusion abnormalities during stress in patients with multivessel disease. The results may be important in patient management and prognosis.

  10. Does perfusion pattern influence stress-induced changes in left ventricular mechanical dyssynchrony on thallium-201-gated SPECT myocardial perfusion imaging?

    PubMed

    Singh, Harmandeep; Patel, Chetan D; Sharma, Punit; Naik, Nitish; Singh, Sandeep; Narang, Rajiv

    2015-02-01

    The relationship between perfusion pattern and stress-induced changes in left ventricular mechanical dyssynchrony (LVMD) on stress-rest thallium-201-gated SPECT myocardial perfusion imaging (Tl-201 SPECT MPI) is not clear. The aim of the study is to assess the relation of perfusion pattern with stress-induced changes in LVMD on Tl-201 MPI. Data of 194 patients who underwent exercise-rest Tl-201 MPI between January to December 2012 at our institute was retrospectively evaluated. Institute Ethical committee approval was obtained. Fifty patients who underwent Tl-201 MPI for suspected CAD and had normal LV perfusion and function on MPI were taken as normal group. Patients with perfusion abnormalities (n = 144) were divided into three groups: ischemia (n = 66), infarct (n = 32), and mixed group (n = 46; ischemia and infarct both). Summed stress score, summed rest score, summed difference score (SDS), and LV ejection fraction (EF) were evaluated. Two LVMD parameters, phase standard deviation (PSD) and phase histogram bandwidth (PHB), were assessed in post-stress and rest MPI images. ΔPSD (post-stress PSD - rest PSD) and ΔPHB (post-stress PHB - rest PHB) were calculated to measure stress-induced changes in LVMD. In all the groups, mean post-stress LVMD parameters were lower as compared to LVMD parameters at rest. Post-stress PSD was significantly lower than rest PSD in all groups. Similar trend was noted with PHB values also, but it was statistically significant in the normal and ischemia group only. Post-stress worsening of at least one of the LVMD parameters was noted in 28 patients and all these patients had perfusion abnormalities. But on subgroup analysis, no difference was found in proportion of patients showing post-stress worsening of LVMD between ischemia (13.6%), infarct (25%), and mixed (23.6%) groups. No significant correlation was found between ΔPSD/ΔPHB and ΔLVEF/SDS in any group. LV mechanical dyssynchrony parameters are smaller in post-exercise stress

  11. Association between retinal hemorrhagic pattern and macular perfusion status in eyes with acute branch retinal vein occlusion

    PubMed Central

    Muraoka, Yuki; Uji, Akihito; Tsujikawa, Akitaka; Murakami, Tomoaki; Ooto, Sotaro; Suzuma, Kiyoshi; Takahashi, Ayako; Iida, Yuto; Miwa, Yuko; Hata, Masayuki; Yoshimura, Nagahisa

    2016-01-01

    This prospective study included 63 eyes with acute branch retinal vein occlusion (BRVO) to evaluate the retinal hemorrhagic patterns at the posterior poles and explore their clinical relevance in macular perfusion differentiation. Retinal hemorrhagic patterns and macular perfusion status were evaluated via fundus photography and fluorescein angiography, respectively. Macular perfusion was judged as nonischemic in 30, ischemic in 28, and undeterminable in 5 among the 63 eyes. Predominant hemorrhagic patterns were flame-shaped in 39 (67.2%) and non-flame-shaped in 19 (32.8%) eyes. All 39 eyes with a flame-shaped hemorrhage showed a nonischemic macula. Of the 19 eyes classified as having a non-flame-shaped hemorrhage, 13 (68.4%) had an ischemic macula and 6 (31.6%) had a nonischemic macula (P < 0.001). Parallelism in eyes with a flame-shaped hemorrhage was higher than in those with a non-flame-shaped hemorrhage (P < 0.001), and in those with a nonischemic macula versus those with an ischemic macula (P < 0.001). The area under the curve for parallelism was 0.975 (P < 0.001), suggesting an accurate diagnostic parameter for macular perfusion differentiation. In conclusion, we objectively evaluated retinal hemorrhagic patterns at the posterior pole in BRVO using the parallelism method, which was useful in differentiating macular perfusion status. PMID:27334338

  12. Computational comparison of regional stress and deformation characteristics in tricuspid and bicuspid aortic valve leaflets.

    PubMed

    Cao, K; Sucosky, P

    2017-03-01

    The bicuspid aortic valve (BAV) is the most common congenital valvular defect and a major risk factor for secondary calcific aortic valve disease. While hemodynamics is presumed to be a potential contributor to this complication, the validation of this theory has been hampered by the limited knowledge of the mechanical stress abnormalities experienced by BAV leaflets and their dependence on the heterogeneous BAV fusion patterns. The objective of this study was to compare computationally the regional and temporal fluid wall shear stress (WSS) and structural deformation characteristics in tricuspid aortic valve (TAV), type-0, and type-I BAV leaflets. Arbitrary Lagrangian-Eulerian fluid-structure interaction models were designed to simulate the flow and leaflet dynamics in idealized TAV, type-0, and type-I BAV geometries subjected to physiologic transvalvular pressure. The regional leaflet mechanics was quantified in terms of temporal shear magnitude (TSM), oscillatory shear index (OSI), temporal shear gradient (TSG), and stretch. The simulations identified regions of WSS overloads and increased WSS bidirectionality (174% increase in temporal shear magnitude, 0.10 increase in OSI on type-0 leaflets) in BAV leaflets relative to TAV leaflets. BAV leaflets also experienced larger radial deformations than TAV leaflets (4% increase in type-0 BAV leaflets). Type-I BAV leaflets exhibited contrasted WSS environments marked by WSS overloads on the non-coronary leaflet and sub-physiologic WSS levels on the fused leaflet. This study provides important insights into the mechanical characteristics of BAV leaflets, which may further our understanding of the role played by hemodynamic forces in BAV disease. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Optimal Design of Aortic Leaflet Prosthesis

    NASA Technical Reports Server (NTRS)

    Ghista, Dhanjoo N.; Reul, Helmut; Ray, Gautam; Chandran, K. B.

    1978-01-01

    The design criteria for an optimum prosthetic-aortic leaflet valve are a smooth washout in the valve cusps, minimal leaflet stress, minimal transmembrane pressure for the valve to open, an adequate lifetime (for a given blood-compatible leaflet material's fatigue data). A rigorous design analysis is presented to obtain the prosthetic tri-leaflet aortic valve leaflet's optimum design parameters. Four alternative optimum leaflet geometries are obtained to satisfy the criteria of a smooth washout and minimal leaflet stress. The leaflet thicknesses of these four optimum designs are determined by satisfying the two remaining design criteria for minimal transmembrane opening pressure and adequate fatigue lifetime, which are formulated in terms of the elastic and fatigue properties of the selected leaflet material - Avcothane-51 (of the Avco-Everett Co. of Massachusetts). Prosthetic valves are fabricated on the basis of the optimum analysis and the resulting detailed engineering drawings of the designs are also presented in the paper.

  14. Optimal Design of Aortic Leaflet Prosthesis

    NASA Technical Reports Server (NTRS)

    Ghista, Dhanjoo N.; Reul, Helmut; Ray, Gautam; Chandran, K. B.

    1978-01-01

    The design criteria for an optimum prosthetic-aortic leaflet valve are a smooth washout in the valve cusps, minimal leaflet stress, minimal transmembrane pressure for the valve to open, an adequate lifetime (for a given blood-compatible leaflet material's fatigue data). A rigorous design analysis is presented to obtain the prosthetic tri-leaflet aortic valve leaflet's optimum design parameters. Four alternative optimum leaflet geometries are obtained to satisfy the criteria of a smooth washout and minimal leaflet stress. The leaflet thicknesses of these four optimum designs are determined by satisfying the two remaining design criteria for minimal transmembrane opening pressure and adequate fatigue lifetime, which are formulated in terms of the elastic and fatigue properties of the selected leaflet material - Avcothane-51 (of the Avco-Everett Co. of Massachusetts). Prosthetic valves are fabricated on the basis of the optimum analysis and the resulting detailed engineering drawings of the designs are also presented in the paper.

  15. Diurnal pattern of sodium excretion in dogs with and without chronically reduced renal perfusion pressure.

    PubMed

    Corea, M; Seeliger, E; Boemke, W; Reinhardt, H W

    1996-01-01

    In 5 conscious dogs the diurnal patterns of urinary sodium excretion (UNaV) were investigated, initially during 1 control day and, thereafter, during 4 days of servo-controlled reduction of renal perfusion pressure (rRPP). The individual dog's mean arterial blood pressure was reduced to 80% of the blood pressure on the control day. This value was always found to be below the threshold for the pressure-dependent renin release. During the entire study period urine was collected in 4-hour intervals and blood samples were taken every 4 h. The dogs were kept on a standardized high sodium and high water intake and were fed once daily at 8.30 h. On the control day, UNaV, urinary flow rate (UV), fractional lithium excretion (FELi) and fractional sodium excretion (FENa) had similar diurnal patterns. They peaked 4-8 h after food intake and decreased to low values during the night. On day 1 of rRPP, UNaV and FENa were maintained at very low levels in all collection periods, whereas the patterns of UV and FELi were unaltered compared with the patterns on the control day. On days 2-4 of rRPP, a clear-cut maximum in the patterns of UNaV and FENa recurred, comparable with the patterns on the control day. However, compared with the control day this maximum was shifted by 4 h towards the night. In contrast, the patterns of UV and FELi remained unchanged compared with the control day. The results indicate that UNaV has a typical time course in conscious, sodium- and water-replete dogs fed once daily. Endogenous stimulation of sodium reabsorption by means of rRPP results in a characteristic 4-hour shift of UNaV and FENa towards the night during rRPP days 2-4. This delay in UNaV seems to be evoked by processes in the distal tubule.

  16. Reversal of diffuse patchy pattern in lung perfusion scan in a case of severe pulmonary arterial hypertension.

    PubMed

    Kodama, Yoshihiko; Abe, Kohtaro; Hosokawa, Kazuya; Ohtani, Kisho; Nagao, Michinobu; Hirooka, Yoshitaka; Sunagawa, Kenji

    2015-01-01

    A diffuse patchy pattern in the perfusion scan of the lung is a hallmark of severe pulmonary arterial hypertension (PAH). However, the mechanisms of this unique pattern remain uncertain. We here present the case of a 19-year-old woman with severe PAH who demonstrated reversal of the diffuse patchy pattern with improvement of pulmonary blood flow within a month after upfront triple combination therapy. Our case is a first report showing reversibility of diffuse patchy pattern by a short-term treatment in severe PAH. These findings suggest the possibility that the mechanisms underlying the diffuse patchy pattern may involve reversible vasoconstriction in addition to remodeling of small pulmonary arteries.

  17. Patterns of histological changes following hepatic electrolytic ablation in an ex-vivo perfused model.

    PubMed

    Gravante, Gianpiero; Ong, Seok Ling; West, Kevin; McGregor, Angus; Maddern, Guy J; Metcalfe, Matthew S; Lloyd, David M; Dennison, Ashley R

    2012-10-01

    Electrolytic ablation (EA) destroys the liver by releasing toxic radicles and producing modifications in the local pH without increasing the tissue temperature. We assessed the histological changes produced by EA using an ex-vivo perfused model. Five porcine livers were harvested, preserved in ice and reperfused for six hours in an extracorporeal circuit using autologous normothermic blood. One hour after reperfusion EA was performed and liver biopsies collected at the end of the experiments. The main necrotic zone consisted of coagulative necrosis, sinusoidal dilatation and haemorrhage with an unusual morphological pattern. The coagulative necrosis and haemorrhage affected mainly the peripheral area of the lobule with relative sparing of the area surrounding the centrilobular vein. Contrasting with this sinusoidal dilatation appeared to be more prominent in the centrilobular area. EA produces patterns of tissue destruction that have not been observed with the more commonly used thermal techniques. Further studies should obtain more information about the influence of adjacent biliary and vascular structures so that appropriate clinical trials can be designed.

  18. Prostaglandin E1 Increases Microcirculation in Random Pattern Flaps on Rats Measured with Laser Doppler Perfusion Imaging

    PubMed Central

    Sneistrup, Christian; Berg, Thomas Moe

    2017-01-01

    Background: Reconstructive procedures with pedicled and free flaps are associated with a risk of ischemia. Prostaglandin E1 (PGE1) is a hormone-like substance with known antiischemic and tissue-protective effects. The aim of this study was to evaluate the effect of PGE1 on the microcirculation in random pattern skin flaps on rats. Methods: Twenty-four rats were divided into 2 groups: an intervention group given PGE1 for 6 hours and a control group given saline. The flap (2 × 10 cm) was created on the back of the rats, and the microcirculation was monitored with laser Doppler perfusion imaging in 5 different zones (1, proximal; 5, distal) before surgery and after 60, 180, and 360 minutes postoperatively. Results: Before surgery, there was no difference in the perfusion in any zones between the intervention group and the control group. The mean perfusion values in zone 1 in the intervention group were significantly higher than those in the control group at 60, 180, and 360 minutes postoperatively (P = 0.02, P = 0.05, and P = 0.04, respectively). At 360 minutes, we also found significantly higher levels of perfusion in the intervention group in zones 4 and 5 (P = 0.05 and P = 0.03, respectively) compared with the controls. Comparing the perfusion at 360 to 60 minutes in the intervention group, we found a significant increase in microcirculation in all zones, which were not seen in the control group. Conclusion: PGE1 increased perfusion in the dermal random pattern flaps on rats. PMID:28203503

  19. Document of the Month: German Propaganda Leaflets

    ERIC Educational Resources Information Center

    Byers, CeCe; Alexander, Mary

    1978-01-01

    Excerpts from two propaganda leaflets distributed by Germany during World War I to demoralize American soldiers. Teaching suggestions encourage students to examine the leaflets' tone, guess who the authors might have been, and analyze the leaflets as examples of a propaganda technique. (AV)

  20. Spatio-temporal cerebral blood flow perfusion patterns in cortical spreading depression

    NASA Astrophysics Data System (ADS)

    Verisokin, Andrey Yu.; Verveyko, Darya V.; Postnov, Dmitry E.

    2017-04-01

    Cortical spreading depression (CSD) is an example of one of the most common abnormalities in biophysical brain functioning. Despite the fact that there are many mathematical models describing the cortical spreading depression (CSD), most of them do not take into consideration the role of redistribution of cerebral blood flow (CBF), that results in the formation of spatio-temporal patterns. The paper presents a mathematical model, which successfully explains the CBD role in the CSD process. Numerical study of this model has revealed the formation of stationary dissipative structures, visually analogous to Turing structures. However, the mechanism of their formation is not diffusion. We show these structures occur due to another type of spatial coupling, that is related to tissue perfusion rate. The proposed model predicts that at similar state of neurons the distribution of blood flow and oxygenation may by different. Currently, this effect is not taken into account when the Blood oxygen-level dependent (BOLD) contrast imaging used in functional magnetic resonance imaging (fMRI). Thus, the diagnosis on the BOLD signal can be ambiguous. We believe that our results can be used in the future for a more correct interpretation of the data obtained with fMRI, NIRS and other similar methods for research of the brain activity.

  1. Rapid casting of patterned vascular networks for perfusable engineered three-dimensional tissues

    NASA Astrophysics Data System (ADS)

    Miller, Jordan S.; Stevens, Kelly R.; Yang, Michael T.; Baker, Brendon M.; Nguyen, Duc-Huy T.; Cohen, Daniel M.; Toro, Esteban; Chen, Alice A.; Galie, Peter A.; Yu, Xiang; Chaturvedi, Ritika; Bhatia, Sangeeta N.; Chen, Christopher S.

    2012-09-01

    In the absence of perfusable vascular networks, three-dimensional (3D) engineered tissues densely populated with cells quickly develop a necrotic core. Yet the lack of a general approach to rapidly construct such networks remains a major challenge for 3D tissue culture. Here, we printed rigid 3D filament networks of carbohydrate glass, and used them as a cytocompatible sacrificial template in engineered tissues containing living cells to generate cylindrical networks that could be lined with endothelial cells and perfused with blood under high-pressure pulsatile flow. Because this simple vascular casting approach allows independent control of network geometry, endothelialization and extravascular tissue, it is compatible with a wide variety of cell types, synthetic and natural extracellular matrices, and crosslinking strategies. We also demonstrated that the perfused vascular channels sustained the metabolic function of primary rat hepatocytes in engineered tissue constructs that otherwise exhibited suppressed function in their core.

  2. Rapid casting of patterned vascular networks for perfusable engineered three-dimensional tissues.

    PubMed

    Miller, Jordan S; Stevens, Kelly R; Yang, Michael T; Baker, Brendon M; Nguyen, Duc-Huy T; Cohen, Daniel M; Toro, Esteban; Chen, Alice A; Galie, Peter A; Yu, Xiang; Chaturvedi, Ritika; Bhatia, Sangeeta N; Chen, Christopher S

    2012-09-01

    In the absence of perfusable vascular networks, three-dimensional (3D) engineered tissues densely populated with cells quickly develop a necrotic core. Yet the lack of a general approach to rapidly construct such networks remains a major challenge for 3D tissue culture. Here, we printed rigid 3D filament networks of carbohydrate glass, and used them as a cytocompatible sacrificial template in engineered tissues containing living cells to generate cylindrical networks that could be lined with endothelial cells and perfused with blood under high-pressure pulsatile flow. Because this simple vascular casting approach allows independent control of network geometry, endothelialization and extravascular tissue, it is compatible with a wide variety of cell types, synthetic and natural extracellular matrices, and crosslinking strategies. We also demonstrated that the perfused vascular channels sustained the metabolic function of primary rat hepatocytes in engineered tissue constructs that otherwise exhibited suppressed function in their core.

  3. Rapid casting of patterned vascular networks for perfusable engineered 3D tissues

    PubMed Central

    Miller, Jordan S.; Stevens, Kelly R.; Yang, Michael T.; Baker, Brendon M.; Nguyen, Duc-Huy T.; Cohen, Daniel M.; Toro, Esteban; Chen, Alice A.; Galie, Peter A.; Yu, Xiang; Chaturvedi, Ritika; Bhatia, Sangeeta N.; Chen, Christopher S.

    2012-01-01

    In the absence of perfusable vascular networks, three-dimensional (3D) engineered tissues densely populated with cells quickly develop a necrotic core [1]. Yet the lack of a general approach to rapidly construct such networks remains a major challenge for 3D tissue culture [2–4]. Here, we 3D printed rigid filament networks of carbohydrate glass, and used them as a cytocompatible sacrificial template in engineered tissues containing living cells to generate cylindrical networks which could be lined with endothelial cells and perfused with blood under high-pressure pulsatile flow. Because this simple vascular casting approach allows independent control of network geometry, endothelialization, and extravascular tissue, it is compatible with a wide variety of cell types, synthetic and natural extracellular matrices (ECMs), and crosslinking strategies. We also demonstrated that the perfused vascular channels sustained the metabolic function of primary rat hepatocytes in engineered tissue constructs that otherwise exhibited suppressed function in their core. PMID:22751181

  4. Brain perfusion SPECT in the mouse: normal pattern according to gender and age.

    PubMed

    Apostolova, Ivayla; Wunder, Andreas; Dirnagl, Ulrich; Michel, Roger; Stemmer, Nina; Lukas, Mathias; Derlin, Thorsten; Gregor-Mamoudou, Betina; Goldschmidt, Jürgen; Brenner, Winfried; Buchert, Ralph

    2012-12-01

    Regional cerebral blood flow (rCBF) is a useful surrogate marker of neuronal activity and a parameter of primary interest in the diagnosis of many diseases. The increasing use of mouse models spawns the demand for in vivo measurement of rCBF in the mouse. Small animal SPECT provides excellent spatial resolution at adequate sensitivity and is therefore a promising tool for imaging the mouse brain. This study evaluates the feasibility of mouse brain perfusion SPECT and assesses the regional pattern of normal Tc-99m-HMPAO uptake and the impact of age and gender. Whole-brain kinetics was compared between Tc-99m-HMPAO and Tc-99m-ECD using rapid dynamic planar scans in 10 mice. Assessment of the regional uptake pattern was restricted to the more suitable tracer, HMPAO. Two HMPAO SPECTs were performed in 18 juvenile mice aged 7.5 ± 1.5weeks, and in the same animals at young adulthood, 19.1 ± 4.0 weeks (nanoSPECT/CTplus, general purpose mouse apertures: 1.2kcps/MBq, 0.7mm FWHM). The 3-D MRI Digital Atlas Database of an adult C57BL/6J mouse brain was used for region-of-interest (ROI) analysis. SPECT images were stereotactically normalized using SPM8 and a custom made, left-right symmetric HMPAO template in atlas space. For testing lateral asymmetry, each SPECT was left-right flipped prior to stereotactical normalization. Flipped and unflipped SPECTs were compared by paired testing. Peak brain uptake was similar for ECD and HMPAO: 1.8 ± 0.2 and 2.1 ± 0.6 %ID (p=0.357). Washout after the peak was much faster for ECD than for HMPAO: 24 ± 7min vs. 4.6 ± 1.7h (p=0.001). The general linear model for repeated measures with gender as an intersubject factor revealed an increase in relative HMPAO uptake with age in the neocortex (p=0.018) and the hippocampus (p=0.012). A decrease was detected in the midbrain (p=0.025). Lateral asymmetry, with HMPAO uptake larger in the left hemisphere, was detected primarily in the neocortex, both at juvenile age (asymmetry index AI=2.7 ± 1

  5. Patients’ views on electronic patient information leaflets

    PubMed Central

    2015-01-01

    Background: Information in society and in health care is currently undergoing a transition from paper to digital formats, and the main source of information will probably be electronic in the future. Objective: To explore patients’ use and perceptions of the patient information leaflet included in the medication package, and their attitude towards a transition to an electronic version. Methods: The data was collected during October to November 2014 among individuals in South-Eastern Sweden, using a questionnaire (n=406, response rate 78%) and interviews (n=15). Results: The questionnaire showed that the majority of the respondents (52%) occasionally read the patient information leaflet, 37% always read it, and 11% never read it. Almost half of the patients (41%) were positive towards reading the patient information leaflet electronically while 32% were hesitant and 26% neutral. A majority of the patients would request to get the patient information leaflet printed at the pharmacy if it was not included in the package. There were differences in attitude related to age and gender. The interviews showed that patients had mixed views on a transition to an electronic patient information leaflet. The patients perceived several positive aspects with an electronic patient information leaflet but were concerned about elderly patients. Conclusion: Although many were positive towards reading the patient information leaflet electronically, the majority prefer the patient information leaflet in paper form. Providing appropriate and useful eHealth services for patients to access the patient information leaflet electronically, along with education, could prepare patients for a transition to electronic patient information leaflet. PMID:27382423

  6. The resting perfusion pattern associates with functional decline in type 2 diabetes.

    PubMed

    Dai, Weiying; Duan, Wenna; Alfaro, Freddy J; Gavrieli, Anna; Kourtelidis, Fotini; Novak, Vera

    2017-09-14

    We investigated the relationships between cerebral blood flow (CBF), cognitive, and mobility decline in type 2 diabetes mellitus (T2DM) over a 2-year period. Seventy-three participants (41 T2DM and 32 controls) were evaluated using volumetric CBF with arterial spin labeling perfusion magnetic resonance imaging at baseline and at the 2-year follow-up. Regions with significant CBF differences between T2DM participants and controls at baseline were detected using voxel-wise analysis. Correlation analysis was performed to investigate the association between regional CBF and cognitive or mobility performance over the 2-year span. Compared to controls, participants with T2DM had decreased CBF in the resting-state default mode, visual, and cerebellum networks. Greater decrease in longitudinal CBF values at these regions over a 2-year span was associated with worse gait, memory and executive functions, and higher baseline insulin resistance and worse baseline cognitive performance. In T2DM, impairment of resting regional perfusion is closely related to worse cognitive and mobility performance. Insulin resistance may further contribute to regional perfusion deficit in T2DM. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Diffusion coefficients in leaflets of bilayer membranes.

    PubMed

    Seki, Kazuhiko; Mogre, Saurabh; Komura, Shigeyuki

    2014-02-01

    We study diffusion coefficients of liquid domains by explicitly taking into account the two-layered structure called leaflets of the bilayer membrane. In general, the velocity fields associated with each leaflet are different and the layers sliding past each other cause frictional coupling. We obtain analytical results of diffusion coefficients for a circular liquid domain in a leaflet, and quantitatively study their dependence on the interleaflet friction. We also show that the diffusion coefficients diverge in the absence of coupling between the bilayer and solvents, even when the interleaflet friction is taken into account. In order to corroborate our theory, the effect of the interleaflet friction on the correlated diffusion is examined.

  8. The lld mutation in Pisum sativum used as a genetic tool to discern the plant leaflet/leaf developmental process.

    PubMed

    Sharma, Vishakha; Tripathi, Bhumi Nath; Kumar, Sushil

    2013-06-01

    Leaves of P. sativum the double mutant genotype tendril-less (tl) leaflet-development (lld), due to the action of lld mutation, produce many leaflets that are aborted at different stages of development. Morphological, vein pattern and histological observations showed that aborted leaflets became cup/bell/trumpet (cup) shaped because of segmental differentiation in the leaflet primordium. Cup's inside lamina surface was adaxial and outer surfaces of cup and its stem were abaxial. The lld cups were phenotypically homologous to aborted leaves described in Arabidopsis thaliana mutants, angustifolia and those which underexpressed the HD-ZIP III proteins. Leaflet primordium was found to grow and establish three dimensional polarities apex-downwards. Primordium produced lateral outgrowth on one side of midvein. Differentiation, in the outgrowth of secondary veins, whose xylem tissues faced each other, established the adaxial-abaxial polarity. Lateral outgrowth then developed a cavity which got bounded by future adaxial epidermis. Further growth, veinlet formation, differentiation of palisade parenchyma and spongy parenchyma followed. Opening of lateral outgrowth at its outer midline produced a flat leaflet with lateral lamina spans. The structural and functional correspondence between leaflet and simple leaves suggested commonality between leaf and leaflet development mechanisms. A molecular model for the lld led leaflet abortion was also provided.

  9. The benefits of prescription information leaflets (1).

    PubMed Central

    Gibbs, S; Waters, W E; George, C F

    1989-01-01

    1. Prescription information leaflets (PILs) giving information about non-steroidal anti-inflammatory drugs (NSAIDs), beta-adrenoceptor antagonists and inhaled bronchodilators were evaluated in three small Hampshire towns, while a fourth, in which no leaflets were distributed, acted as a control. 2. Seven hundred and nineteen (82%) patients prescribed one of these medicines agreed to be interviewed in their homes, 1 to 2 weeks after the medicine had been prescribed. Four hundred and nineteen of them had received leaflets, while 300 received no written information. Two hundred and sixty patients received their leaflets from a pharmacist while 159 were given them by their general practitioner. 3. Patients who received leaflets were better informed about every item of knowledge tested, except for the name of the medicine. Awareness of the side effects showed the greatest improvement, but there was no evidence that these leaflets produced spurious side effects. 4. Much improved levels of satisfaction were recorded amongst patients who received leaflets, especially those for NSAIDs (P less than 0.001) and for beta-adrenoceptor antagonists (P less than 0.01). 5. Subsequently, three hundred and fifty-eight (77%) of the patients prescribed either a NSAID or a beta-adrenoceptor antagonist 1 year earlier responded to a postal questionnaire. The benefits in terms of knowledge and satisfaction were still apparent, although less marked than previously. Of the patients still taking beta-adrenoceptor antagonists 70% had retained their leaflets over the intervening 12 months. 6. Ninety-seven per cent of patients read their leaflet regardless of whether it was distributed by a general practitioner or pharmacist. However, those who obtained it from a pharmacist tended to be more knowledgeable and satisfied. 7. We conclude that patients welcome the idea of receiving PILs. They improve patients' knowledge of how to take their medicines correctly and their awareness of potential side

  10. Polymersomes with Salt-Induced Leaflet Rearrangement

    NASA Astrophysics Data System (ADS)

    Lee, Yoon Kyeung; Yu, Changqian; Granick, Steve

    2014-03-01

    Polymersomes, composed of two leaflets of amphiphilic diblock copolymers, become unstable when presented with external stimuli such as osmotic perturbation and invasive ions. Here, using a homebuilt hydrogel-based microfluidic device, we quantify their shape transformations in response to fine-tuning of the local ionic environment. We demonstrate a model system involving PBD-PEO (polybutadiene-co-polyethylene oxide). Inward budding of these polymersomes reflects difference of surface area between inner and outer leaflets rather than the conventional osmotic imbalance.

  11. Soft tissue attenuation patterns in stress myocardial perfusion SPECT images: a comparison between supine and upright acquisition systems.

    PubMed

    Chawla, David; Rahaby, Mouyyad; Amin, Amit P; Vashistha, Raj; Alyousef, Tareq; Martinez, Hector X; Doukky, Rami

    2011-04-01

    Soft tissue attenuation patterns and their interaction with body habitus and gender in Single Photon Emission Computed Tomography (SPECT)-myocardial perfusion imaging (MPI) of upright patient-position acquisition systems are not well described. In a retrospective cross-sectional study, we compared the prevalence and patterns of soft tissue attenuation in two groups of normal SPECT-MPI studies acquired by supine (n = 263) vs upright (n = 212) acquisition systems. Attenuation patterns observed in the study population were: anterior (22.3%), inferior (51.6%) and lateral (18.1%). Anterior attenuation was significantly less in those imaged upright (6.1% vs 35.4%), P < .001; particularly among women (9.5% vs 50.7%), P < .001. Inferior attenuation was more common among women imaged upright (49.5% vs 13.5%), P < .001; but was not affected by imaging position among men. Lateral attenuation was more prevalent in the upright group (24.1% vs 13.3%), P = .002; and had a strong association with female gender (P < .001) and BMI ≥ 30 (P < .001). Upright SPECT-MPI acquisition is associated with a unique attenuation pattern which is vastly different than the supine position. Female gender strongly impacted this attenuation pattern, particularly obese women. Our study is the first to describe, in details, the attenuation patterns with upright imaging and is critical for the accurate interpretation of SPECT-MPI acquired with upright systems.

  12. Perfusion functional MRI reveals cerebral blood flow pattern under psychological stress

    NASA Astrophysics Data System (ADS)

    Wang, Jiongjiong; Rao, Hengyi; Wetmore, Gabriel S.; Furlan, Patricia M.; Korczykowski, Marc; Dinges, David F.; Detre, John A.

    2005-12-01

    Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right prefrontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response. anterior cingulate cortex | arterial spin labeling | right prefrontal cortex

  13. Robotic mitral valve repair for degenerative posterior leaflet prolapse

    PubMed Central

    Javadikasgari, Hoda; Suri, Rakesh M.; Tappuni, Bassman; Lowry, Ashley M.; Mihaljevic, Tomislav; Mick, Stephanie

    2017-01-01

    Background Robotic mitral valve (MV) repair is the least invasive surgical approach to the MV and provides unparalleled access to the valve. We sought to assess technical aspects and clinical outcomes of robotic MV repair for isolated posterior leaflet prolapse by examining the first 623 such cases performed in a tertiary care center. Methods We reviewed the first 623 patients (mean age 56±9.7 years) with isolated posterior leaflet prolapse who underwent robotic primary MV repair from 01/2006 to 11/2013. All procedures were performed via right chest access with femoral perfusion for cardiopulmonary bypass. Results MV repair was attempted in all patients; 622 (99.8%) underwent MV repair and only 1 (0.2%) converted to replacement. After an initial attempt at robotic MV repair, 8 (1.3%) patients were converted to sternotomy as a result of management of residual mitral regurgitation (n=3), bleeding (n=1), difficulties with surgical exposure (n=2), aortic valve injury (n=1), and aortic dissection (n=1). Intraoperative post-repair echocardiography confirmed that all patients left the operating room with MR graded as mild or less, and pre-discharge echocardiography confirmed mild or less MR in 573 (99.1%). There was no hospital death, sternal wound infection, or renal failure. Seven (1.1%) patients suffered a stroke, 11 (1.8%) patients underwent re-exploration for bleeding, and 111 (19%) experienced new-onset atrial fibrillation. The mean intensive care unit length of stay and hospital length of stay were 29±17 hours and 4.6±1.6 days, respectively. Conclusions At a large tertiary care referral center, robotic MV repair for posterior prolapse is associated with zero mortality, infrequent operative morbidity, and near 100% successful repair. The combination of a patient selection algorithm and increased experience improved clinical outcomes and procedural efficiency. PMID:28203538

  14. The readability and suitability of sexual health promotion leaflets.

    PubMed

    Corcoran, Nova; Ahmad, Fatuma

    2016-02-01

    To investigate the readability and suitability of sexual health promotion leaflets. Application of SMOG, FRY and SAM tests to assess the readability and suitability of a selection of sexual health leaflets. SMOG and FRY scores illustrate an average reading level of grade 9. SAM scores indicate that 59% of leaflets are superior in design and 41% are average in design. Leaflets generally perform well in the categories of content, literacy demand, typography and layout. They perform poorly in use of graphics, learning stimulation/motivation and cultural appropriateness. Sexual health leaflets have a reading level that is too high. Leaflets perform well on the suitability scores indicating they are reasonably suitable. There are a number of areas where sexual health leaflets could improve their design. Numerous practical techniques are suggested for improving the readability and suitability of sexual health leaflets. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Signal transduction across cellular membranes can be mediated by coupling of the clustering of anchored proteins in both leaflets

    NASA Astrophysics Data System (ADS)

    Yue, Tongtao; Zhang, Xianren

    2012-01-01

    One key question in signal transduction is how the signal is relayed from the outer leaflet of a cellular membrane to the inner leaflet. Using a simulation model, a mechanism for the mediation of signal transduction is proposed here in which the coupling between membrane proteins in different leaflets can be achieved by the clustering of anchored proteins, without recruiting transmembrane proteins. Depending on the hydrophobic length of the anchored proteins, three coupling patterns, including face-to-face clustering, interdigitated clustering, and weak-coupled clustering, are observed in this work. This observation provides a possible explanation of how a particular downstream signaling pathway is selected.

  16. Evaluating the quality of patient leaflets about renal replacement therapy across UK renal units.

    PubMed

    Winterbottom, Anna; Conner, Mark; Mooney, Andrew; Bekker, Hilary L

    2007-08-01

    Enhancing patient participation is a priority for renal services. Good quality information is fundamental to facilitate patient involvement, but in other health contexts it has been found to be sub-optimal. This research aims to audit the provision of patient information by renal units and charities and to assess the quality of written information about dialysis treatment options. All UK renal units were sent a questionnaire about the patient information they provided. Renal units and charities that provided dialysis leaflets were asked to forward copies. Leaflet quality and content were assessed by a coding frame informed by information and decision aid checklists. Out of 105, 67 completed questionnaires were returned. Services provide patients with large amounts of information in several media (leaflets, meetings with nurses and patients, videos); computers were not used frequently. Out of 47, 32 units forwarded leaflets about dialysis, and 31 different leaflets. Most leaflets were difficult to understand and rarely included risk information or treatment limitations. No leaflets included techniques to assist patient involvement or decision-making; their primary goal was to inform. These data suggest an unsystematic pattern of information provision across the UK. Vast resources have been spent on providing information to patients that is difficult to comprehend and incomplete. Research needs to identify which resources are effective in meeting patient needs and at what point in their illness. A centralized system to guide renal services in the design and development of information resources may help meet the differing goals of education, choice facilitation and preparation for self-management.

  17. Optimal Elastomeric Scaffold Leaflet Shape for Pulmonary Heart Valve Leaflet Replacement

    PubMed Central

    Fan, Rong; Bayoumi, Ahmed S.; Chen, Peter; Hobson, Christopher M.; Wagner, William R.; Mayer, John E.; Sacks, Michael S.

    2012-01-01

    Surgical replacement of the pulmonary valve (PV) is a common treatment option for congenital pulmonary valve defects. Engineered tissue approaches to develop novel PV replacements are intrinsically complex, and will require methodical approaches for their development. Single leaflet replacement utilizing an ovine model is an attractive approach in that candidate materials can be evaluated under valve level stresses in blood contact without the confounding effects of a particular valve design. In the present study an approach for optimal leaflet shape design based on finite element (FE) simulation of a mechanically anisotropic, elastomeric scaffold for PV replacement is presented. The scaffold was modeled as an orthotropic hyperelastic material using a generalized Fung-type constitutive model. The optimal shape of the fully loaded PV replacement leaflet was systematically determined by minimizing the difference between the deformed shape obtained from FE simulation and an ex-vivo microCT scan of a native ovine PV leaflet. Effects of material anisotropy, dimensional changes of PV root, and fiber orientation on the resulting leaflet deformation were investigated. In-situ validation demonstrated that the approach could guide the design of the leaflet shape for PV replacement surgery. PMID:23294966

  18. Optimal elastomeric scaffold leaflet shape for pulmonary heart valve leaflet replacement.

    PubMed

    Fan, Rong; Bayoumi, Ahmed S; Chen, Peter; Hobson, Christopher M; Wagner, William R; Mayer, John E; Sacks, Michael S

    2013-02-22

    Surgical replacement of the pulmonary valve (PV) is a common treatment option for congenital pulmonary valve defects. Engineered tissue approaches to develop novel PV replacements are intrinsically complex, and will require methodical approaches for their development. Single leaflet replacement utilizing an ovine model is an attractive approach in that candidate materials can be evaluated under valve level stresses in blood contact without the confounding effects of a particular valve design. In the present study an approach for optimal leaflet shape design based on finite element (FE) simulation of a mechanically anisotropic, elastomeric scaffold for PV replacement is presented. The scaffold was modeled as an orthotropic hyperelastic material using a generalized Fung-type constitutive model. The optimal shape of the fully loaded PV replacement leaflet was systematically determined by minimizing the difference between the deformed shape obtained from FE simulation and an ex-vivo microCT scan of a native ovine PV leaflet. Effects of material anisotropy, dimensional changes of PV root, and fiber orientation on the resulting leaflet deformation were investigated. In-situ validation demonstrated that the approach could guide the design of the leaflet shape for PV replacement surgery. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Psychiatric profiles and patterns of cerebral blood flow in focal epilepsy: interactions between depression, obsessionality, and perfusion related to the laterality of the epilepsy.

    PubMed Central

    Schmitz, E B; Moriarty, J; Costa, D C; Ring, H A; Ell, P J; Trimble, M R

    1997-01-01

    OBJECTIVES: In a study of patients with focal epilepsy the hypothesis was explored that different measurements of psychopathology are related to specific distributions of cerebral perfusion. METHODS: Forty patients had SPECT performed with (99m)Tc-HMPAO. In addition, patients received a psychiatric evaluation with the following psychiatric questionnaires: the Beck depression inventory, the Leyton obsessionality inventory, the Bear-Fedio questionnaire, and the social stress and support interview. Patients were analysed in two groups according to the laterality of the epilepsy. Nine patients were excluded based on poor quality scans (n = 1), unlateralised epilepsy (n = 4), and left or ambidextrous handedness (n = 4). RESULTS: There were no overall differences between the left and right epilepsy groups on measures of psychopathology. Associations were found between scores on some of the rating scales and regional cerebral blood flow. Specifically, for patients with left sided epilepsy, higher scores on the Beck depression inventory were associated with lower contralateral temporal and bilateral frontal perfusion, and higher occipital perfusion. For patients with right sided epilepsy higher scores on the Leyton obsessionality inventory were associated with increased perfusion in ipsilateral temporal, thalamic, and basal ganglia regions and bilateral frontal regions. CONCLUSION: The results do not support the notion that lateralised epileptogenic lesions are associated with different levels of depression, obsessionality, or personality traits. They support the view that certain psychopathological symptom patterns are related to specific regional dysfunctions depending on the laterality of a hemispheric lesion. PMID:9153601

  20. Evidence for Leaflet-Dependent Redistribution of Charged Molecules in Fluid Supported Phospholipid Bilayers

    PubMed Central

    Shreve, Andrew P.; Howland, Michael C.; Sapuri-Butti, Annapoorna R.; Allen, Toby W.; Parikh, Atul N.

    2009-01-01

    The asymmetric distribution of charged molecules between the leaflets of solid-substrate-supported phospholipid bilayers is studied using imaging ellipsometry, fluorescence microscopy, and numerical solutions of the Poisson-Boltzmann equation. Experiments are facilitated by the use of patterned substrates that allow for side-by-side comparison of lipid monolayers and supported bilayers. On silica surfaces, negatively charged lipid components are shown to be enriched in the outer leaflet of a supported bilayer system at modest salt concentrations. The approaches developed provide a general means for determining asymmetries of charged components in supported lipid bilayers. PMID:19007257

  1. Patient information leaflets for extracorporeal shock wave lithotripsy: questionnaire survey

    PubMed Central

    Askari, A; Shergill, I

    2012-01-01

    Objectives To compare the level of information provided in extracorporeal shock wave lithotripsy (ESWL) patient information leaflets in the London and East of England Deaneries Design All trusts in the London and East of England Deanery who offer an ESWL service were contacted and leaflets were compared Setting London and East of England Deanery Participants Alan Askari, Iqbal Shergill Main outcome measures Examination of key information that was communicated to ESWL patients via leaflets Results 12 trusts responded across the two deaneries. There was significant variation in the amount of information provided in the leaflets with some leaflets not containing an adequate level of instruction or information to patients Conclusions The authors propose that a national standardised information leaflet should be incorporated with the British Association of Urological Surgeons (BAUS) procedure specific information leaflet for ESWL procedures PMID:22666532

  2. Distinctive Patterns of Three-Dimensional Arterial Spin-Labeled Perfusion Magnetic Resonance Imaging in Subtypes of Acute Ischemic Stroke.

    PubMed

    Kohno, Naoto; Okada, Kazunori; Yamagata, Shingo; Takayoshi, Hiroyuki; Yamaguchi, Shuhei

    2016-07-01

    Ischemic penumbra in acute ischemic stroke (AIS) can be evaluated using arterial spin-labeled (ASL) perfusion magnetic resonance imaging (MRI). We used three-dimensional ASL-MRI to examine patients with different stroke subtypes and the clinical utility of the method within 24 hours of AIS onset. The 55 male and 48 female patients (mean age, 79.0 years) underwent diffusion-weighted imaging (DWI), fluid-attenuated inversion recovery imaging, magnetic resonance angiography, and pulsed continuous ASL perfusion imaging to determine stroke subtype, hypoperfused ASL area, and neurological deficit severity (National Institutes of Health Stroke Scale). Arterial transit artifacts, indicative of occlusive regions or collateral flow, and other stroke indices were compared. ASL hypoperfusion was detected in 3 of 9 patients with transient ischemic attack (TIA), 2 of 27 patients with lacunar infarction (LI), 19 of 31 patients with atherothrombotic infarction (AT), and 30 of 36 patients with cardiogenic embolic infarction (CE). ASL abnormalities were significantly less frequent in LI than in AT and CE, and more frequent in CE than in TIA. ASL abnormalities were more prevalent in patients with medium-to-large DWI-assessed lesions than in those with small lesions on DWI. Patients with medium-sized lesions following AT and CE had a high frequency of diffusion-perfusion mismatch. In 4 of the 5 patients who underwent intravenous thrombolytic therapy, ASL hypoperfusion and diffusion-perfusion mismatch were improved and the occluded arteries were recanalized. ASL perfusion studies may provide useful clinical information allowing diffusion-perfusion mismatch detection and treatment selection in AIS patients, depending on stroke subtype. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  3. Precocious progression of tissue maturation instructs basipetal initiation of leaflets in Chelidonium majus subsp. asiaticum (Papaveraceae).

    PubMed

    Ikeuchi, Momoko; Tatematsu, Kiyoshi; Yamaguchi, Takahiro; Okada, Kiyotaka; Tsukaya, Hirokazu

    2013-06-01

    On a compound leaf, leaflet primordia are repetitively formed along the apical-basal axis, with the direction varying among taxa. Why and how the directions vary among species is yet to be solved, although a change in a single factor was proposed to cause the variation. In this study, we compared two species in the Papaveraceae with different directions of leaflet initiation, Chelidonium majus subsp. asiaticum (basipetal) and Eschscholzia californica (acropetal). Because E. californica has been studied in some detail, we focused on C. majus and asked how basipetal pattern is achieved. • Since only immature leaf primordial tissue has leaflet-generating competency, we performed histological and gene expression analyses on markers of the tissue maturation state. In addition, we performed a time-course analysis of leaf primordial growth. • Quantitative reverse transcription-PCR analysis demonstrated that a putative regulator of tissue maturation in C. majus, the CINCINNATA homolog, had higher expression in apical parts than in basal parts during the organogenetic phase. In contrast, expression of the CIN homolog was not elevated in either the apical or basal parts in E. californica during the organogenetic phase. • In C. majus, apical parts of leaf primordia have already lost leaflet-generating competency during the organogenetic phase. We propose that precocious progression of the maturation process instructs basipetal progression of leaflet initiation in C. majus. This is not the mirror image of data on E. californica, which shows the opposite direction in leaflet formation, indicating that variation in direction is not attributable to a change in a single factor.

  4. Reconstruction of anterior mitral leaflet using autologous pericardial patch combined with posterior leaflet sliding for active infective endocarditis.

    PubMed

    Kimura, Satoshi; Yamaki, Yuta; Umesue, Masayoshi

    2014-04-01

    We report a case of active infective endocarditis in a young adult, affecting the anterior and posterior leaflets extensively. The patient underwent a mitral valve repair with extended sliding repair on the posterior leaflet and reconstruction using an autologous pericardial patch supported by an artificial chord on the anterior leaflet. Although we finally needed commissure closing for successful repair, we aggressively achieved a repair-oriented strategy using several techniques in a young patient who may have required mitral valve replacement.

  5. Ln is a key regulator of leaflet shape and number of seeds per pod in soybean.

    PubMed

    Jeong, Namhee; Suh, Su Jeoung; Kim, Min-Hee; Lee, Seukki; Moon, Jung-Kyung; Kim, Hong Sig; Jeong, Soon-Chun

    2012-12-01

    Narrow leaflet soybean (Glycine max) varieties tend to have more seeds per pod than broad leaflet varieties. Narrow leaflet in soybean is conferred by a single recessive gene, ln. Here, we show that the transition from broad (Ln) to narrow leaflet (ln) is associated with an amino acid substitution in the EAR motif encoded by a gene (designated Gm-JAGGED1) homologous to Arabidopsis JAGGED (JAG) that regulates lateral organ development and the variant exerts a pleiotropic effect on fruit patterning. The genomic region that regulates both the traits was mapped to a 12.6-kb region containing only one gene, Gm-JAG1. Introducing the Gm-JAG1 allele into a loss-of-function Arabidopsis jagged mutant partially restored the wild-type JAG phenotypes, including leaf shape, flower opening, and fruit shape, but the Gm-jag1 (ln) and EAR-deleted Gm-JAG1 alleles in the jagged mutant did not result in an apparent phenotypic change. These observations indicate that despite some degree of functional change of Gm-JAG1 due to the divergence from Arabidopsis JAG, Gm-JAG1 complemented the functions of JAG in Arabidopsis thaliana. However, the Gm-JAG1 homoeolog, Gm-JAG2, appears to be sub- or neofunctionalized, as revealed by the differential expression of the two genes in multiple plant tissues, a complementation test, and an allelic analysis at both loci.

  6. Myocardial perfusion SPECT identifies patients with left bundle branch block patterns at high risk for future coronary events.

    PubMed

    ten Cate, Tim J F; Kelder, Johannes C; Plokker, Herbert W M; Verzijlbergen, J Fred; van Hemel, Norbert M

    2010-04-01

    The value of myocardial perfusion SPECT (MPS) for patients with left bundle branch block (LBBB) or right ventricular apical (RVA) pacing seems reduced. The prognosis of patients with only abnormal activation related perfusion defects (AARD) due to LBBB or RVA-pacing is similar to those with a normal MPS. We assessed the prognostic value of MPS in patients with LBBB or RVA pacing. Patients with LBBB or RVA pacing referred for vasodilator stress MPS between April 2002 and January 2006 were analyzed. Group 1 are patients with normal MPS and MPS with AARD. Group 2 are patients with an MPS with a perfusion defect extending outside the AARD area. Events were cardiac death, acute myocardial infarction and coronary revascularization. In Group 1 (101 patients) 12 events and in Group 2 (96 patients) 45 events occurred during a mean follow-up of 2.6 +/- 1.5 years. The prognosis of Group 2 was significantly worse (49%) compared with Group 1 (91%). The annual cardiac death rate was 0.7%/year in Group 1 and 6.4%/year in Group 2 (P < .001). The prognosis of patients with LBBB was not different from those with RVA pacing. Group 2 had a significantly worse cardiac prognosis compared to Group 1. The annual cardiac death rate of <1% in Group 1 warrants a watchful waiting strategy, whereas the cardiac death rate in Group 2 warrants aggressive invasive coronary strategies.

  7. Prescription information leaflets: a pilot study in general practice.

    PubMed Central

    George, C F; Waters, W E; Nicholas, J A

    1983-01-01

    Leaflets containing information about medicines were issued to 56 patients prescribed penicillins and 43 patients prescribed non-steroidal anti-inflammatory drugs. The patients were interviewed between four and 10 days later and their responses compared with those of 65 patients prescribed penicillin and 33 prescribed nonsteroidal anti-inflammatory drugs who did not receive a leaflet. Patients who received a leaflet were more likely to be completely satisfied with their treatment and with the information they had been given. They were also more likely to know the name of their medicine and much more aware of potential unwanted effects. Although there was no evidence that knowledge increased the incidence of adverse effects, when these did occur they were more likely to be recognised as being due to the medicine. Further studies of other leaflets are warranted, including leaflets for drugs that are taken long term. PMID:6414626

  8. Computer modeling of the combined effects of perfusion, electrical conductivity, and thermal conductivity on tissue heating patterns in radiofrequency tumor ablation.

    PubMed

    Ahmed, Muneeb; Liu, Zhengjun; Humphries, Stanley; Goldberg, S Nahum

    2008-11-01

    To use an established computer simulation model of radiofrequency (RF) ablation to characterize the combined effects of varying perfusion, and electrical and thermal conductivity on RF heating. Two-compartment computer simulation of RF heating using 2-D and 3-D finite element analysis (ETherm) was performed in three phases (n = 88 matrices, 144 data points each). In each phase, RF application was systematically modeled on a clinically relevant template of application parameters (i.e., varying tumor and surrounding tissue perfusion: 0-5 kg/m(3)-s) for internally cooled 3 cm single and 2.5 cm cluster electrodes for tumor diameters ranging from 2-5 cm, and RF application times (6-20 min). In the first phase, outer thermal conductivity was changed to reflect three common clinical scenarios: soft tissue, fat, and ascites (0.5, 0.23, and 0.7 W/m- degrees C, respectively). In the second phase, electrical conductivity was changed to reflect different tumor electrical conductivities (0.5 and 4.0 S/m, representing soft tissue and adjuvant saline injection, respectively) and background electrical conductivity representing soft tissue, lung, and kidney (0.5, 0.1, and 3.3 S/m, respectively). In the third phase, the best and worst combinations of electrical and thermal conductivity characteristics were modeled in combination. Tissue heating patterns and the time required to heat the entire tumor +/-a 5 mm margin to >50 degrees C were assessed. Increasing background tissue thermal conductivity increases the time required to achieve a 50 degrees C isotherm for all tumor sizes and electrode types, but enabled ablation of a given tumor size at higher tissue perfusions. An inner thermal conductivity equivalent to soft tissue (0.5 W/m- degrees C) surrounded by fat (0.23 W/m- degrees C) permitted the greatest degree of tumor heating in the shortest time, while soft tissue surrounded by ascites (0.7 W/m- degrees C) took longer to achieve the 50 degrees C isotherm, and complete ablation

  9. Guidelines for sizing pericardium for aortic valve leaflet grafts

    PubMed Central

    Hammer, Peter E.; del Nido, Pedro J.

    2013-01-01

    Surgical repair of the aortic valve using leaflet grafts made from pericardium has been shown to be a viable option, particularly in children, in whom valve replacement has strong disadvantages. We present guidelines for sizing treated autologous pericardium to fabricate a leaflet graft for single leaflet replacement. Both our clinical experience and experimental evidence indicate that effective repairs are best achieved using a semicircular graft with diameter 10–15% greater than the sinotubular junction diameter in diastole. We also provide a simple formula to allow adjusting these guidelines to account for variation in valve geometry and tissue properties. PMID:23816114

  10. The imbrication technique: an alternative to the sliding leaflet technique.

    PubMed

    Hashim, Peter W; Assi, Roland; Hashim, Sabet W

    2014-09-01

    Systolic anterior motion (SAM) represents a common and troublesome complication of mitral valve repair. The prevention of SAM has traditionally been based on the sliding leaflet technique, which involves resection of posterior leaflet tissue. However, this approach has not been universally adopted owing to its technical difficulty and inconsistent efficacy. We present an imbrication technique that avoids additional leaflet resection and achieves a reliable prevention of SAM. The approach has been successfully implemented in the treatment of 124 consecutive patients at high risk for SAM. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Evaluation of mosaic pattern areas in HRCT with Min-IP reconstructions in patients with pulmonary hypertension: could this evaluation replace lung perfusion scintigraphy?

    PubMed

    Rossi, A; Attinà, D; Borgonovi, A; Buia, F; De Luca, F; Guidalotti, P L; Fughelli, P; Galiè, N; Zompatori, M

    2012-01-01

    The aim of this study is to evaluate a possible correlation between areas of lung attenuation, found in minimum intensity projection (Min-IP) reconstruction images performed with high resolution computed tomography without contrast medium (HRCT), and areas of lung perfusion alteration, found in lung perfusion scintigraphy (LPS). Two independent radiologists, unaware of LPS results, evaluated retrospectively a group of 113 patients affected by pulmonary hypertension (HP) of different aetiology. These have been examined in a period of two years in our centre both by spiral computed tomography (CT) with and without contrast-medium and by LPS. The final diagnosis was determined on clinical data, right heart catheterisation and contrast enhanced CT in angiographic phase (CTPA). We reconstructed the Min-IP images of lung parenchyma in all the cases both in HRCT without contrast-medium, and in contrast enhanced CT in angiographic phase (CTPA) in axial, sagittal and coronal planes. The obtained images were qualitatively graded into three categories of pulmonary attenuation: homogeneous, inhomogeneous with non-segmental patchy defects, inhomogeneous with segmental defects. The same criteria of classification were used also for LPS images. In the group of patients with chronic thromboembolic pulmonary hypertension (CTEPH) we also compared the number of areas of lung attenuation found in Min-IP images in HRCT without contrast-medium, and their exact localization, with not perfused areas in LPS. Gold standard for the diagnosis of pulmonary embolism was spiral contrast enhanced CT in angiographic phase (CTPA). In all cases we found exact correspondence between the Min-IP images in HRCT with and without contras agent. The attenuation pattern seen on Min-IP images was concordant with those of LPS in 96 out of 113 patients (85%). In the remaining 17 cases (15%) it was discordant: in 12 cases inhomogeneous in Min-IP images (7 with non-segmental patchy defects, 5 with segmental

  12. A Parametric Computational Study of the Impact of Non-circular Configurations on Bioprosthetic Heart Valve Leaflet Deformations and Stresses: Possible Implications for Transcatheter Heart Valves.

    PubMed

    Duraiswamy, Nandini; Weaver, Jason D; Ekrami, Yasamin; Retta, Stephen M; Wu, Changfu

    2016-06-01

    Although generally manufactured as circular devices with symmetric leaflets, transcatheter heart valves can become non-circular post-implantation, the impact of which on the long-term durability of the device is unclear. We investigated the effects of five non-circular (EllipMajor, EllipMinor, D-Shape, TriVertex, TriSides) annular configurations on valve leaflet stresses and valve leaflet deformations through finite element analysis. The highest in-plane principal stresses and strains were observed under an elliptical configuration with an aspect ratio of 1.25 where one of the commissures was on the minor axis of the ellipse. In this elliptical configuration (EllipMinor), the maximum principal stress increased 218% and the maximum principal strain increased 80% as compared with those in the circular configuration, and occurred along the free edge of the leaflet whose commissures were not on the minor axis (i.e., the "stretched" leaflet). The D-Shape configuration was similar to this elliptical configuration, with the degree to which the leaflets were stretched or sagging being less than the EllipMinor configuration. The TriVertex and TriSides configurations had similar leaflet deformation patterns in all three leaflets and similar to the Circular configuration. In the D-Shape, TriVertex, and TriSides configurations, the maximum principal stress was located near the commissures similar to the Circular configuration. In the EllipMinor and EllipMajor configurations, the maximum principal stress occurred near the center of the free edge of the "stretched" leaflets. These results further affirm recommendations by the International Standards Organization (ISO) that pre-clinical testing should consider non-circular configurations for transcatheter valve durability testing.

  13. PIV validation of blood-heart valve leaflet interaction modelling.

    PubMed

    Kaminsky, R; Dumont, K; Weber, H; Schroll, M; Verdonck, P

    2007-07-01

    The aim of this study was to validate the 2D computational fluid dynamics (CFD) results of a moving heart valve based on a fluid-structure interaction (FSI) algorithm with experimental measurements. Firstly, a pulsatile laminar flow through a monoleaflet valve model with a stiff leaflet was visualized by means of Particle Image Velocimetry (PIV). The inflow data sets were applied to a CFD simulation including blood-leaflet interaction. The measurement section with a fixed leaflet was enclosed into a standard mock loop in series with a Harvard Apparatus Pulsatile Blood Pump, a compliance chamber and a reservoir. Standard 2D PIV measurements were made at a frequency of 60 bpm. Average velocity magnitude results of 36 phase-locked measurements were evaluated at every 10 degrees of the pump cycle. For the CFD flow simulation, a commercially available package from Fluent Inc. was used in combination with inhouse developed FSI code based on the Arbitrary Lagrangian-Eulerian (ALE) method. Then the CFD code was applied to the leaflet to quantify the shear stress on it. Generally, the CFD results are in agreement with the PIV evaluated data in major flow regions, thereby validating the FSI simulation of a monoleaflet valve with a flexible leaflet. The applicability of the new CFD code for quantifying the shear stress on a flexible leaflet is thus demonstrated.

  14. Perfusion patterns in postictal 99mTc-HMPAO SPECT after coregistration with MRI in patients with mesial temporal lobe epilepsy

    PubMed Central

    Hogan, R; Cook, M.; Binns, D.; Desmond, P.; Kilpatrick, C.; Murrie, V.; Morris, K.

    1997-01-01

    OBJECTIVES—To assess patterns of postictal cerebral blood flow in the mesial temporal lobe by coregistration of postictal 99mTc-HMPAO SPECT with MRI in patients with confirmed mesial temporal lobe epilepsy.
METHODS—Ten postictal and interictal 99mTc-HMPAO SPECT scans were coregistered with MRI in 10 patients with confirmed mesial temporal lobe epilepsy. Volumetric tracings of the hippocampus and amygdala from the MRI were superimposed on the postictal and interictal SPECT. Asymmetries in hippocampal and amygdala SPECT signal were then calculated using the equation:
 % Asymmetry =100 × (right − left) / (right + left)/2.
RESULTS—In the postictal studies, quantitative measurements of amygdala SPECT intensities were greatest on the side of seizure onset in all cases, with an average % asymmetry of 11.1, range 5.2-21.9.Hippocampal intensities were greatest on the side of seizure onset in six studies, with an average % asymmetry of 9.6, range 4.7-12.0.In four scans the hippocampal intensities were less on the side of seizure onset, with an average % asymmetry of 10.2, range 5.7-15.5.There was no localising quantitative pattern in interictal studies.
CONCLUSIONS—Postictal SPECT shows distinctive perfusion patterns when coregistered with MRI, which assist in lateralisation of temporal lobe seizures. Hyperperfusion in the region of the amygdala is more consistently lateralising than hyperperfusion in the region of the hippocampus in postictal studies.

 PMID:9285464

  15. Analysis of Contrast-Enhanced Ultrasound Perfusion Patterns and Time-Intensity Curves for Metastatic Lymph Nodes From Lung Cancer: Preliminary Results.

    PubMed

    Yin, Shanshan; Cui, Qiuli; Wang, Song; Fan, Zhihui; Yan, Kun

    2017-09-06

    To retrospectively summarize the similarities and differences in contrast-enhanced ultrasound (US) findings for lymph node metastasis from adenocarcinoma, squamous carcinoma, and small cell lung cancer. Patients who had received contrast-enhanced US examinations and had a histologic diagnosis of supraclavicular lymph node metastasis from lung cancer were included. The perfusion patterns on contrast-enhanced US images and time-intensity curve parameters were analyzed for the different pathologic types. The microvascular density and microvascular diameter were evaluated. Totally, 61 patients were enrolled in this study, including 26 cases with lung squamous carcinoma, 26 with lung adenocarcinoma, and 9 with small cell lung cancer. Contrast-enhanced US perfusion showed no significant differences in enhancement uniformity during the arterial phase and in the presence of unenhanced areas of metastatic lymph nodes with the 3 different pathologic origins (P > .05), but fewer unenhanced areas could be seen in metastatic lymph nodes from adenocarcinoma. The analysis of the time-intensity curve parameters showed that there were significant differences in the peak intensity between metastatic lymph nodes from lung squamous carcinoma and lung adenocarcinoma (P < .05). The microvascular density of metastatic lymph nodes from adenocarcinoma was significantly higher than that of metastatic lymph nodes from squamous carcinoma and small cell lung cancer (P < .001; P = .0444), whereas the microvascular diameter of metastatic lymph nodes from adenocarcinoma was significantly smaller than that from squamous carcinoma and small cell lung cancer (P = .0277; P < .001). Effects of the pathologic diagnosis should be considered when analyzing quantitative parameters of metastatic lymph nodes during contrast-enhanced US examinations, even in the same organ. © 2017 by the American Institute of Ultrasound in Medicine.

  16. [EFFECT OF EDUCATIONAL LEAFLETS ON KNOWLEDGE AND ATTITUDE TO TUBERCULOSIS AMONG HOMELESS PERSONS IN TOKYO, JAPAN].

    PubMed

    Kawatsu, Lisa; Uchimura, Kazuhiro; Watabe, Hiroyuki; Kaguraoka, Sumi; Kubota, Yuka; Sakakibara, Marie; Ishikawa, Nobukatsu

    2015-08-01

    Delay in seeking care is one of the critical issues in tuberculosis (TB) control among homeless persons in Japan. Yet knowledge of and attitude towards TB among homeless persons have remained unclear and limited efforts have been made to disseminate information related to TB among homeless persons. To evaluate the effect of TB leaflets, produced and distributed to homeless persons by a group of ex-homeless TB patients, and to understand what homeless persons know about TB. Self-administered questionnaire was conducted among homeless persons before and after distribution of the TB leaflets. Changes in the responses to each question were also subjected to principal component analysis to group questions into types according to response patterns and identify constructs of TB-related knowledge. Results of 88 participants were analyzed. TB knowledge score related to risks and symptoms significantly improved after the intervention (from 54.3% to 70.6%, p < 0.05), while knowledge on treatment cost did not. Two components were identified, namely, the "improvement in TB impression" and "improvement in TB knowledge". TB leaflets were effective in improving certain aspects of TB knowledge. However, its effect on knowledge regarding treatment cost, which may be crucial in improving delay, was limited and thus the messages need to be revised.

  17. Influence of the aortic valve leaflets on the fluid-dynamics in aorta in presence of a normally functioning bicuspid valve.

    PubMed

    Bonomi, D; Vergara, C; Faggiano, E; Stevanella, M; Conti, C; Redaelli, A; Puppini, G; Faggian, G; Formaggia, L; Luciani, G B

    2015-11-01

    In this work, we consider the blood fluid-dynamics in the ascending aorta in presence of a normally functioning bicuspid aortic valve (BAV). In particular, we perform an unsteady finite element study in real geometries with physiological velocity boundary conditions at the inlet to assess the effect of the inclusion of the leaflets on the fluid-dynamic abnormalities characterizing BAV cases. To this aim, we perform a comparison in two geometries (a dilated and a non-dilated ones) among three scenarios which are built up for each geometry: BAV without leaflets, BAV with leaflets, and tricuspid case with leaflets. For each case, we compute four indices quantifying flow asymmetry, reversal flows, helical patterns, and wall shear stresses. Our results show that the inclusion of the leaflets increases the fluid-dynamics abnormalities, especially for the non-dilated configuration, which presents a greater increment of the indices. In particular, we observe that the values of the time-averaged wall shear stress and of the systolic jet asymmetry increase by approximatively 100 and 40%, respectively, when considering the leaflets.

  18. A study of the flow-leaflet interaction

    NASA Astrophysics Data System (ADS)

    Ledesma, R.; Zenit, R.; Pulos, G.

    2008-11-01

    The manufacture of prosthetic heart valves is a relatively simple process. Valves made with biomaterials simply copy the ``design'' of the original ones, because of the limited understanding of the physical mechanism involved in the proper performance of valves. The identification of the parameters that determine the valve performance will help to improve the prosthetic designs and to minimize the health complications. In this work we study the flow-leaflet interaction in a pulsating flow, with the purpose of evaluating the influence of the material properties and leaflet dimensions. A 2D flow channel was design to obtain measurements of the leaflet deflection, for different flow conditions. Using a PIV system, measurements of the flow velocity fields are also obtained. Preliminary results show that the deflection of the leaflet and the proper open-close cycle, that determines the valve performance, is directly related to the leaflet length, thickness and material properties. We have identified the range of parameters for which the valve performance is acceptable.

  19. The developmental trajectory of leaflet morphology in wild tomato species.

    PubMed

    Chitwood, Daniel H; Headland, Lauren R; Kumar, Ravi; Peng, Jie; Maloof, Julin N; Sinha, Neelima R

    2012-03-01

    Leaves between species vary in their size, serration, complexity, and shape. However, phylogeny is not the only predictor of leaf morphology. The shape of a leaf is the result of intricate developmental processes, including heteroblastic progression (changes in leaf size and shape at different nodes) and the developmental stage of an organ. The leaflets that arise from complex leaves are additionally modified by their positioning along the proximal-distal axis of a leaf and whether they fall on the left or right side of leaves. Even further, leaves are environmentally responsive, and their final shape is influenced by environmental inputs. Here, we comprehensively describe differences in leaflet shape between wild tomato (Solanum section Lycopersicon) species using a principal component analysis on elliptical Fourier descriptors arising from >11,000 sampled leaflets. We leverage differences in developmental rate to approximate a developmental series, which allows us to resolve the confounding differences in intrinsic leaflet form and developmental stage along positions of the heteroblastic leaf series and proximal-distal axis of leaves. We find that the resulting developmental trajectory of organs at different positions along these axes are useful for describing the changes in leaflet shape that occur during the shade avoidance response in tomato. We argue that it is the developmental trajectory, the changes in shape that occur over developmental time in organs reiterated at multiple positions, that is the relevant phenotype for discerning differences between populations and species, and to understand the underlying developmental processes that change during evolution.

  20. Ordered Raft Domains Induced by Outer Leaflet Sphingomyelin in Cholesterol-Rich Asymmetric Vesicles

    PubMed Central

    Lin, Qingqing; London, Erwin

    2015-01-01

    Sphingolipid- and cholesterol-rich liquid-ordered (Lo) lipid domains (rafts) are thought to be important organizing elements in eukaryotic plasma membranes. How they form in the sphingolipid-poor cytosolic (inner) membrane leaflet is unclear. Here, we characterize how outer-leaflet Lo domains induce inner-leaflet-ordered domains, i.e., interleaflet coupling. Asymmetric vesicles studied contained physiologically relevant cholesterol levels (∼37 mol %), a mixture of SM (sphingomyelin) and DOPC (dioleoylphosphatidylcholine) in their outer leaflets, and DOPC in their inner leaflets. Lo domains were observed in both leaflets, and were in register, indicative of coupling between SM-rich outer-leaflet-ordered domains and inner-leaflet-ordered domains. For asymmetric vesicles with outer-leaflet egg SM or milk SM, a fluorescent lipid with unsaturated acyl chains (NBD-DOPE) was depleted in both the outer- and inner-leaflet-ordered domains. This suggests the inner-leaflet-ordered domains were depleted in unsaturated lipid (i.e., DOPC) and thus rich in cholesterol. For asymmetric vesicles containing egg SM, outer-leaflet Lo domains were also depleted in a saturated fluorescent lipid (NBD-DPPE), while inner-leaflet Lo domains were not. This indicates that inner- and outer-leaflet Lo domains can have significantly different physical properties. In contrast, in asymmetric vesicles containing outer-leaflet milk SM, which has long acyl chains capable of interdigitating into the inner leaflet, both outer- and inner-leaflet Lo domains were depleted, to a similar extent, in NBD-DPPE. This is indicative of interdigitation-enhanced coupling resulting in inner- and outer-leaflet Lo domains with similar physical properties. PMID:25954879

  1. A quality assessment of orthodontic patient information leaflets.

    PubMed

    Seehra, Jadbinder; Cockerham, Laura; Pandis, Nikolaos

    2016-01-01

    Patient information leaflets (PILs) are often used to reinforce and provide further information relating to treatment choices, risks, and alternatives. An assessment of the quality of commonly used orthodontic patient information leaflets is lacking. A cross-sectional assessment of patient information leaflets from two international orthodontic societies was undertaken. The quality of each leaflet was assessed using the DISCERN instrument. The readability of each leaflet was assessed using the Flesch Reading Ease instrument, Flesch-Kincaid Grade Level and Simple Measure of Gobbledygook (SMOG) index. Descriptive statistics followed by univariate analysis was conducted. Thirty-six patient information leaflets were identified. Reporting of DISCERN instrument items relating to aims, description of sources, details of additional sources, consequences of no treatment, possible treatment options, and support for a shared decision process was of low quality. The overall quality score for the total sample was 44. The median Flesch Reading Ease, Flesch-Kincaid Grade Level, and SMOG index scores were 70 (interquartile range (IQR) 53.3-73.9), 7.2 (IQR 6-9.7), and 7.3 (IQR 6.7-9.1), respectively. There was a significant difference between the quality (-8.00, 95% CI: -14.62, -1.38, p < 0.001), Flesch Reading Ease (-22.30, 95% CI: -26.77, 17.83, p < 0.001) and the Flesch-Kincaid Grade Level (3.80, 95% CI: 2.74, 4.86, p < 0.001) scores between the two societies' PILs. In relation to the DISCERN instrument, the quality of orthodontic PILs is deemed of moderate quality. There is a significant difference between the quality scores and the readability of PILs from different societies.

  2. Interlayer micromechanics of the aortic heart valve leaflet.

    PubMed

    Buchanan, Rachel M; Sacks, Michael S

    2014-08-01

    While the mechanical behaviors of the fibrosa and ventricularis layers of the aortic valve (AV) leaflet are understood, little information exists on their mechanical interactions mediated by the GAG-rich central spongiosa layer. Parametric simulations of the interlayer interactions of the AV leaflets in flexure utilized a tri-layered finite element (FE) model of circumferentially oriented tissue sections to investigate inter-layer sliding hypothesized to occur. Simulation results indicated that the leaflet tissue functions as a tightly bonded structure when the spongiosa effective modulus was at least 25 % that of the fibrosa and ventricularis layers. Novel studies that directly measured transmural strain in flexure of AV leaflet tissue specimens validated these findings. Interestingly, a smooth transmural strain distribution indicated that the layers of the leaflet indeed act as a bonded unit, consistent with our previous observations (Stella and Sacks in J Biomech Eng 129:757-766, 2007) of a large number of transverse collagen fibers interconnecting the fibrosa and ventricularis layers. Additionally, when the tri-layered FE model was refined to match the transmural deformations, a layer-specific bimodular material model (resulting in four total moduli) accurately matched the transmural strain and moment-curvature relations simultaneously. Collectively, these results provide evidence, contrary to previous assumptions, that the valve layers function as a bonded structure in the low-strain flexure deformation mode. Most likely, this results directly from the transverse collagen fibers that bind the layers together to disable physical sliding and maintain layer residual stresses. Further, the spongiosa may function as a general dampening layer while the AV leaflets deforms as a homogenous structure despite its heterogeneous architecture.

  3. Age-associated patterns in gray matter volume, cerebral perfusion and BOLD oscillations in children and adolescents.

    PubMed

    Bray, Signe

    2017-05-01

    Healthy brain development involves changes in brain structure and function that are believed to support cognitive maturation. However, understanding how structural changes such as grey matter thinning relate to functional changes is challenging. To gain insight into structure-function relationships in development, the present study took a data driven approach to define age-related patterns of variation in gray matter volume (GMV), cerebral blood flow (CBF) and blood-oxygen level dependent (BOLD) signal variation (fractional amplitude of low-frequency fluctuations; fALFF) in 59 healthy children aged 7-18 years, and examined relationships between modalities. Principal components analysis (PCA) was applied to each modality in parallel, and participant scores for the top components were assessed for age associations. We found that decompositions of CBF, GMV and fALFF all included components for which scores were significantly associated with age. The dominant patterns in GMV and CBF showed significant (GMV) or trend level (CBF) associations with age and a strong spatial overlap, driven by increased signal intensity in default mode network (DMN) regions. GMV, CBF and fALFF additionally showed components accounting for 3-5% of variability with significant age associations. However, these patterns were relatively spatially independent, with small-to-moderate overlap between modalities. Independence of age effects was further demonstrated by correlating individual subject maps between modalities: CBF was significantly less correlated with GMV and fALFF in older children relative to younger. These spatially independent effects of age suggest that the parallel decline observed in global GMV and CBF may not reflect spatially synchronized processes. Hum Brain Mapp 38:2398-2407, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  4. [An automatic system controlled by microcontroller for carotid sinus perfusion].

    PubMed

    Yi, X L; Wang, M Y; Fan, Z Z; He, R R

    2001-08-01

    To establish a new method for controlling automatically the carotid perfusion pressure. A cheap practical automatic perfusion unit based on AT89C2051 micro controller was designed. The unit, LDB-M perfusion pump and the carotid sinus of an animal constituted an automatic perfusion system. This system was able to provide ramp and stepwise updown perfusion pattern and has been used in the research of baroreflex. It can insure the precision and reproducibility of perfusion pressure curve, and improve the technical level in corresponding medical field.

  5. 27 CFR 5.41 - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Bottle cartons, booklets and leaflets. 5.41 Section 5.41 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF DISTILLED SPIRITS...

  6. 27 CFR 5.41 - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottle cartons, booklets and leaflets. 5.41 Section 5.41 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF DISTILLED SPIRITS...

  7. 27 CFR 5.41 - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Bottle cartons, booklets and leaflets. 5.41 Section 5.41 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF DISTILLED SPIRITS...

  8. 27 CFR 5.41 - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Bottle cartons, booklets and leaflets. 5.41 Section 5.41 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL LABELING AND ADVERTISING OF DISTILLED SPIRITS...

  9. 27 CFR 5.41 - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Bottle cartons, booklets and leaflets. 5.41 Section 5.41 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL LABELING AND ADVERTISING OF DISTILLED SPIRITS...

  10. Regulatory agencies' recommendations for medicine information leaflets: Are they in line with research findings?

    PubMed

    Young, Amber; Tordoff, June; Smith, Alesha

    2017-03-04

    The design of medicine information leaflets can determine whether a leaflet will be read or discarded by patients. It may also influence patients' ability to understand the information about their medicines within the leaflet. Researchers compared regulatory agencies' recommendations for medicine information leaflet design from New Zealand, the United Kingdom, Europe, and the United States against recommended good design principles to determine the appropriateness, comprehensiveness, and consistency of their recommendations. Recommendations for medicine information leaflets varied between the regulatory agencies. There were some inconsistencies between the recommendations and some gaps were identified. There was little regulatory guidance given to creators of medicine information leaflets in New Zealand compared to other countries, and this could lead to manufacturer-produced information leaflets of a poorer quality. Up-to-date and enforceable guidance for creators of medicine information leaflets should be provided in all countries to ensure they are of an appropriate standard.

  11. Readability of medicinal package leaflets: a systematic review.

    PubMed

    Pires, Carla; Vigário, Marina; Cavaco, Afonso

    2015-01-01

    OBJECTIVE To review studies on the readability of package leaflets of medicinal products for human use. METHODS We conducted a systematic literature review between 2008 and 2013 using the keywords "Readability and Package Leaflet" and "Readability and Package Insert" in the academic search engine Biblioteca do Conhecimento Online, comprising different bibliographic resources/databases. The preferred reporting items for systematic reviews and meta-analyses criteria were applied to prepare the draft of the report. Quantitative and qualitative original studies were included. Opinion or review studies not written in English, Portuguese, Italian, French, or Spanish were excluded. RESULTS We identified 202 studies, of which 180 were excluded and 22 were enrolled [two enrolling healthcare professionals, 10 enrolling other type of participants (including patients), three focused on adverse reactions, and 7 descriptive studies]. The package leaflets presented various readability problems, such as complex and difficult to understand texts, small font size, or few illustrations. The main methods to assess the readability of the package leaflet were usability tests or legibility formulae. Limitations with these methods included reduced number of participants; lack of readability formulas specifically validated for specific languages (e.g., Portuguese); and absence of an assessment on patients literacy, health knowledge, cognitive skills, levels of satisfaction, and opinions. CONCLUSIONS Overall, the package leaflets presented various readability problems. In this review, some methodological limitations were identified, including the participation of a limited number of patients and healthcare professionals, the absence of prior assessments of participant literacy, humor or sense of satisfaction, or the predominance of studies not based on role-plays about the use of medicines. These limitations should be avoided in future studies and be considered when interpreting the results.

  12. Mitral Valve Mechanics Following Posterior Leaflet Patch Augmentation

    PubMed Central

    Rahmani, Azadeh; Rasmussen, Ann Q.; Honge, Jesper L.; Ostli, Bjorn; Levine, Robert A.; Hagège, Albert; Nygaard, Hans; Nielsen, Sten L.; Jensen, Morten O.

    2013-01-01

    Background and aim of the study Attention towards the optimization of mitral valve repair methods is increasing. Patch augmentation is one strategy used to treat functional ischemic mitral regurgitation (FIMR). The study aim was to investigate the force balance changes in specific chordae tendineae emanating from the posterior papillary muscle in a FIMR-simulated valve, following posterior leaflet patch augmentation. Methods Mitral valves were obtained from 12 pigs (body weight 80 kg). An in vitro test set-up simulating the left ventricle was used to hold the valves. The left ventricular pressure was regulated with water to simulate different static pressures during valve closure. A standardized oval pericardial patch (17 × 29 mm) was introduced into the posterior leaflet from mid P2 to the end of the P3 scallop. Dedicated miniature transducers were used to record the forces exerted on the chordae tendineae. Data were acquired before and after 12 mm posterior and 5 mm apical posterior papillary muscle displacement to simulate the effect from one of the main contributors of FIMR, before and after patch augmentation. Results The effect of displacing the posterior papillary muscle induced tethering on the intermediate chordae tendineae to the posterior leaflet, and resulted in a 39.8% force increase (p = 0.014). Posterior leaflet patch augmentation of the FIMR valve induced a 31.1% force decrease (p = 0.007). There was no difference in force between the healthy and the repaired valve simulations (p = 0.773). Conclusion Posterior leaflet patch augmentation significantly reduced the forces exerted on the intermediate chordae tendineae from the posterior papillary muscle following FIMR simulation. As changes in chordal tension lead to a redistribution of the total stress exerted on the valve, patch augmentation may have an adverse long-term influence on mitral valve function and remodeling. PMID:23610985

  13. Diet and Colorectal Cancer Risk: Evaluation of a Nutrition Education Leaflet

    ERIC Educational Resources Information Center

    Dyer, K. J.; Fearon, K. C. H.; Buckner, K.; Richardson, R. A.

    2005-01-01

    Objective: To evaluate the effect of a needs-based, nutrition education leaflet on nutritional knowledge. Design: Comparison of nutritional knowledge levels before and after exposure to a nutrition education leaflet. Setting: A regional colorectal out-patient clinic in Edinburgh. Method: A nutrition education leaflet, based on an earlier…

  14. Diet and Colorectal Cancer Risk: Evaluation of a Nutrition Education Leaflet

    ERIC Educational Resources Information Center

    Dyer, K. J.; Fearon, K. C. H.; Buckner, K.; Richardson, R. A.

    2005-01-01

    Objective: To evaluate the effect of a needs-based, nutrition education leaflet on nutritional knowledge. Design: Comparison of nutritional knowledge levels before and after exposure to a nutrition education leaflet. Setting: A regional colorectal out-patient clinic in Edinburgh. Method: A nutrition education leaflet, based on an earlier…

  15. Patient information leaflets for medicines: using consumer testing to determine the most effective design.

    PubMed

    Dickinson, D; Raynor, D K; Duman, M

    2001-05-01

    Comprehensive medicine information leaflets for patients are now mandatory across the European Union. In 1997, the European Commission (EC) proposed a prescriptive 'model' for the leaflets and a method for consumer testing. This exploratory study compared consumers' ability to use a leaflet based on the EC model leaflet and an alternative leaflet based on best practice in information design (Mark II). The leaflets were tested in two matched groups of 20 consumers, who were required to find, and understand, 15 pieces of information in the leaflets. The target that each question should be answered correctly by 16 out of 20 consumers, was achieved for three of the 15 points in the EC leaflet, compared with eight in the Mark II leaflet. Open questioning confirmed the problems with the EC leaflet, including a failure to understand key concepts about medicine interactions and contraindications. This research demonstrates the benefits of consumer testing, ensuring that leaflets are patient-orientated. A rigid model leaflet would prevent these benefits from being utilised.

  16. Effects of ozone and water deficit on field-grown soybean: II. Leaflet nonstructural carbohydrates

    SciTech Connect

    Miller, J.E.; Vozzo, S.F.; Patterson, R.P.

    1995-07-01

    Ozone (O{sub 3}) and water deficit can suppress photosynthesis, growth, and yield of crops, and both may alter plant carbohydrate status. Little is known, however, concerning the combined effects of these stresses on C assimilation and nonstructural carbohydrate reserves in field-grown plants. Soybean [Glycine max (L.) Merr. `Young`] plants were subjected to two soil moisture regimes (providing well-watered and periodically water-deficient conditions) and three levels of O{sub 3} concentrations were 0.018, 0.059, and 0.085 {mu}L L{sup -1} (seasonal mean 12 h d{sup -1} concentration). Leaflet carbohydrate concentrations were measured periodically during the growing season. Total soluble carbohydrates (TSCs) (sucrose and hexose) and starch were measured in the center leaflet of the sixth trifoliolate from the apex. Ozone stress suppressed leaflet concentrations of TSCs and starch on most sampling dates. Impacts of water deficit were less consistent, but starch concentrations usually increased when effects were significant. Interactions between the two stresses occurred infrequently, although water stress reduced the negative effects of O{sub 3} on sucrose and TSCs when the data were analyzed over the season. Ozone treatment also slightly increased the proportion of sucrose compared to starch in the total nonstructural carbohydrate (TNC) pool. The response of seasonal mean TNC concentrations, seasonal mean NCER, and seed yield to O{sub 3} followed similar patterns, although TNCs were suppressed more on a relative basis then NCER or yield. 34 refs., 4 figs., 4 tabs.

  17. Effects of Leaflet Design on Transvalvular Gradients of Bioprosthetic Heart Valves.

    PubMed

    Dabiri, Yaghoub; Ronsky, Janet; Ali, Imtiaz; Basha, Ameen; Bhanji, Alisha; Narine, Kishan

    2016-12-01

    Bioprosthetic aortic valves (BAVs) are becoming the prostheses of choice in heart valve replacement. The objective of this paper is to assess the effects of leaflet geometry on the mechanics and hemodynamics of BAVs in a fluid structure interaction model. The curvature and angle of leaflets were varied in 10 case studies whereby the following design parameters were altered: a circular arch, a line, and a parabola for the radial curvature, and a circular arch, a spline, and a parabola for the circumferential curvature. Six different leaflet angles (representative of the inclination of the leaflets toward the surrounding aortic wall) were analyzed. The 3-dimensional geometry of the models were created using SolidWorks, Pointwise was used for meshing, and Comsol Multiphysics was used for implicit finite element calculations. Realistic loading was enforced by considering the time-dependent strongly-coupled interaction between blood flow and leaflets. Higher mean pressure gradients as well as von Mises stresses were obtained with a parabolic or circular curvature for radial curvature or a parabolic or spline curvature for the circumferential curvature. A smaller leaflet angle was associated with a lower pressure gradient, and, a lower von Mises stress. The leaflet curvature and angle noticeably affected the speed of valve opening, and closing. When a parabola was used for circumferential or radial curvature, leaflets displacements were asymmetric, and they opened and closed more slowly. A circular circumferential leaflet curvature, a linear leaflet radial curvature, and leaflet inclination toward the surrounding aortic wall were associated with superior BAVs mechanics.

  18. The enigmatic fast leaflet rotation in Desmodium motorium

    PubMed Central

    Lev-Yadun, Simcha

    2013-01-01

    I propose that the enigmatic leaflet movements in elliptical circles every few minutes of the Indian telegraph (semaphore) plant Desmodium motorium ( = D. gyrans = Hedysarum gyrans = Codariocalyx motorius), which has intrigued scientists for centuries, is a new type of butterfly or general winged arthropod mimicry by this plant. Such leaflet movement may deceive a passing butterfly searching for an un-occupied site suitable to deposit its eggs, that the plant is already occupied. It may also attract insectivorous birds, reptiles or arthropods to the plant because it looks as if it is harboring a potential prey and while they patrol there, they can find insects or other invertebrates that indeed attack the plant. The possibility that diurnal mammalian herbivores may also be deterred by these movements should not be dismissed. PMID:23603964

  19. Readability of medicinal package leaflets: a systematic review

    PubMed Central

    Pires, Carla; Vigário, Marina; Cavaco, Afonso

    2015-01-01

    OBJECTIVE To review studies on the readability of package leaflets of medicinal products for human use. METHODS We conducted a systematic literature review between 2008 and 2013 using the keywords “Readability and Package Leaflet” and “Readability and Package Insert” in the academic search engine Biblioteca do Conhecimento Online, comprising different bibliographic resources/databases. The preferred reporting items for systematic reviews and meta-analyses criteria were applied to prepare the draft of the report. Quantitative and qualitative original studies were included. Opinion or review studies not written in English, Portuguese, Italian, French, or Spanish were excluded. RESULTS We identified 202 studies, of which 180 were excluded and 22 were enrolled [two enrolling healthcare professionals, 10 enrolling other type of participants (including patients), three focused on adverse reactions, and 7 descriptive studies]. The package leaflets presented various readability problems, such as complex and difficult to understand texts, small font size, or few illustrations. The main methods to assess the readability of the package leaflet were usability tests or legibility formulae. Limitations with these methods included reduced number of participants; lack of readability formulas specifically validated for specific languages (e.g., Portuguese); and absence of an assessment on patients literacy, health knowledge, cognitive skills, levels of satisfaction, and opinions. CONCLUSIONS Overall, the package leaflets presented various readability problems. In this review, some methodological limitations were identified, including the participation of a limited number of patients and healthcare professionals, the absence of prior assessments of participant literacy, humor or sense of satisfaction, or the predominance of studies not based on role-plays about the use of medicines. These limitations should be avoided in future studies and be considered when interpreting the

  20. Patient-specific mitral leaflet segmentation from 4D ultrasound.

    PubMed

    Schneider, Robert J; Tenenholtz, Neil A; Perrin, Douglas P; Marx, Gerald R; del Nido, Pedro J; Howe, Robert D

    2011-01-01

    Segmenting the mitral valve during closure and throughout a cardiac cycle from four dimensional ultrasound (4DUS) is important for creation and validation of mechanical models and for improved visualization and understanding of mitral valve behavior. Current methods of segmenting the valve from 4DUS either require extensive user interaction and initialization, do not maintain the valve geometry across a cardiac cycle, or are incapable of producing a detailed coaptation line and surface. We present a method of segmenting the mitral valve annulus and leaflets from 4DUS such that a detailed, patient-specific annulus and leaflets are tracked throughout mitral valve closure, resulting in a detailed coaptation region. The method requires only the selection of two frames from a sequence indicating the start and end of valve closure and a single point near a closed valve. The annulus and leaflets are first found through direct segmentation in the appropriate frames and then by tracking the known geometry to the remaining frames. We compared the automatically segmented meshes to expert manual tracings for both a normal and diseased mitral valve, and found an average difference of 0.59 +/- 0.49 mm, which is on the order of the spatial resolution of the ultrasound volumes (0.5-1.0 mm/voxel).

  1. Photonastic Control of Leaflet Orientation in Melilotus indicus (Fabaceae) 1

    PubMed Central

    Schwartz, Amnon; Gilboa, Sarah; Koller, Dov

    1987-01-01

    Leaflet orientation in Melilotus indicus (L.) All. Is under photonastic control during the day and nyctinastic control during the night, but also exhibits a diaphototropic (solar-tracking) response. Detached leaves with the two lateral leaflets excised were used to study the solar-tracking capability of the terminal leaflet. Perception of the photonastic excitation is located in the pulvinule. The lower (abaxial) and upper (adaxial) surfaces perceive photonastic excitation, which results in concomitant contraction of the side exposed to light and/or expansion of the opposite side. Steady state laminar elevation is determined by the fluence rates of the light incident simultaneously on the opposite sides. Light sensitivity of the lower side exceeds that of the upper. Response to photonastic excitation of either side is affected by angle of incidence of the light, but angular dependence is restricted to a limited range of angle of incidence, which differs for the two sides. This may be accounted for by the different topography of the two pulvinar surfaces and the localization in them of the light-sensitive tissues. Images Fig. 1 Fig. 2 Fig. 3 PMID:16665437

  2. On the bending properties of porcine mitral, tricuspid, aortic, and pulmonary valve leaflets.

    PubMed

    Brazile, Bryn; Wang, Bo; Wang, Guangjun; Bertucci, Robbin; Prabhu, Raj; Patnaik, Sourav S; Butler, J Ryan; Claude, Andrew; Brinkman-Ferguson, Erin; Williams, Lakiesha N; Liao, Jun

    2015-01-01

    The atrioventricular valve leaflets (mitral and tricuspid) are different from the semilunar valve leaflets (aortic and pulmonary) in layered structure, ultrastructural constitution and organization, and leaflet thickness. These differences warrant a comparative look at the bending properties of the four types of leaflets. We found that the moment-curvature relationships in atrioventricular valves were stiffer than in semilunar valves, and the moment-curvature relationships of the left-side valve leaflets were stiffer than their morphological analog of the right side. These trends were supported by the moment-curvature curves and the flexural rigidity analysis (EI value decreased from mitral, tricuspid, aortic, to pulmonary leaflets). However, after taking away the geometric effect (moment of inertia I), the instantaneous effective bending modulus E showed a reversed trend. The overall trend of flexural rigidity (EI: mitral > tricuspid > aortic > pulmonary) might be correlated with the thickness variations among the four types of leaflets (thickness: mitral > tricuspid > aortic > pulmonary). The overall trend of the instantaneous effective bending modulus (E: mitral < tricuspid < aortic < pulmonary) might be correlated to the layered fibrous ultrastructures of the four types of leaflets, of which the fibers in mitral and tricuspid leaflets were less aligned, and the fibers in aortic and pulmonary leaflets were highly aligned. We also found that, for all types of leaflets, moment-curvature relationships are stiffer in against-curvature (AC) bending than in with-curvature bending (WC), which implies that leaflets tend to flex toward their natural curvature and comply with blood flow. Lastly, we observed that the leaflets were stiffer in circumferential bending compared with radial bending, likely reflecting the physiological motion of the leaflets, i.e., more bending moment and movement were experienced in radial direction than circumferential direction.

  3. LYRATE is a key regulator of leaflet initiation and lamina outgrowth in tomato.

    PubMed

    David-Schwartz, Rakefet; Koenig, Daniel; Sinha, Neelima R

    2009-10-01

    Development of the flattened laminar structure in plant leaves requires highly regulated cell division and expansion patterns. Although tight regulation of these processes is essential during leaf development, leaf shape is highly diverse across the plant kingdom, implying that patterning of growth must be amenable to evolutionary change. Here, we describe the molecular identification of the classical tomato (Solanum lycopersicum) mutant lyrate, which is impaired in outgrowth of leaflet primodia and laminar tissues during compound leaf development. We found that the lyrate phenotype results from a loss-of-function mutation of the tomato JAGGED homolog, a well-described positive regulator of cell division in lateral organs. We demonstrate that LYRATE coordinates lateral outgrowth in the compound leaves of tomato by interacting with both the KNOX and auxin transcriptional networks and suggest that evolutionary changes in LYRATE expression may contribute to the fundamental difference between compound and simple leaves.

  4. Effect of Arched Leaflets and Stent Profile on the Hemodynamics of Tri-Leaflet Flexible Polymeric Heart Valves.

    PubMed

    Yousefi, Atieh; Bark, David L; Dasi, Lakshmi P

    2017-02-01

    Polymeric heart valves (PHV) can be engineered to serve as alternatives for existing prosthetic valves due to higher durability and hemodynamics similar to bioprosthetic valves. The purpose of this study is to evaluate the effect of geometry on PHVs coaptation and hemodynamic performance. The two geometric factors considered are stent profile and leaflet arch length, which were varied across six valve configurations. Three models were created with height to diameter ratio of 0.6, 0.7, and 0.88. The other three models were designed by altering arch height to stent diameter ratio, to be 0, 0.081, and 0.116. Particle image velocimetry experiments were conducted on each PHV to characterize velocity, vorticity, turbulent characteristics, effective orifice area, and regurgitant fraction. This study revealed that the presence of arches as well as higher stent profile reduced regurgitant flow down to 5%, while peak systole downstream velocity reduced to 58% and Reynolds Shear Stress values reduced 40%. Further, earlier reattachment of the forward flow jet was observed in PHVs with leaflet arches. These findings indicate that although both geometric factors help diminish the commissural gap during diastole, leaflet arches induce a larger jet opening, yielding to earlier flow reattachment and lower energy dissipation.

  5. Measurement of mitral leaflet and annular geometry and stress after repair of posterior leaflet prolapse: Virtual repair using a patient specific finite element simulation

    PubMed Central

    Ge, Liang; Morrel, William G.; Ward, Alison; Mishra, Rakesh; Zhang, Zhihong; Guccione, Julius M.; Grossi, Eugene A.; Ratcliffe, Mark B.

    2014-01-01

    Background Recurrent mitral regurgitation after mitral valve (MV) repair for degenerative disease occurs at a rate of 2.6% per year and re-operation rate progressively reaches 20% at 19.5 years. We believe that MV repair durability is related to initial post-operative leaflet and annular geometry with subsequent leaflet remodeling due to stress. We tested the hypothesis that MV leaflet and annular stress is increased after MV repair. Methods Magnetic resonance imaging was performed before and intra-operative 3D trans-esophageal echocardiography was performed before and after repair of posterior leaflet (P2) prolapse in a single patient. The repair consisted of triangular resection and annuloplasty band placement. Images of the heart were manually co-registered. The left ventricle and MV were contoured, surfaced and a 3D finite element (FE) model was created. Elements of the P2 region were removed to model leaflet resection and virtual sutures were used to repair the leaflet defect and attach the annuloplasty ring. Results The principal findings of the current study are 1) FE simulation of MV repair is able to accurately predict changes in MV geometry including changes in annular dimensions and leaflet coaptation, 2) average posterior leaflet stress is increased, and 3) average anterior leaflet and annular stress are reduced after triangular resection and mitral annuloplasty. Conclusions We successfully conducted virtual mitral valve prolapse repair using FE modeling methods. Future studies will examine the effects of leaflet resection type as well as annuloplasty ring size and shape. PMID:24630767

  6. Ventilation-perfusion imaging in pulmonary papillomatosis.

    PubMed

    Espinola, D; Rupani, H; Camargo, E E; Wagner, H N

    1981-11-01

    Three children with laryngeal papillomas involving the lungs had serial ventilation-perfusion scintigrams to assess results of therapy designed to reduce the bronchial involvement. Different imaging patterns were observed depending on size, number, and location of lesions. In early parenchymal involvement a ventilation-perfusion mismatch was seen. The initial and follow-up studies correlated well with clinical and radiographic findings. This noninvasive procedure is helpful in evaluating ventilatory and perfusion impairment in these patients as well as their response to treatment.

  7. Ventilation-perfusion imaging in pulmonary papillomatosis

    SciTech Connect

    Espinola, D.; Rupani, H.; Camargo, E.E.; Wagner, H.N. Jr.

    1981-11-01

    Three children with laryngeal papillomas involving the lungs had serial ventilation-perfusion scintigrams to assess results of therapy designed to reduce the bronchial involvement. Different imaging patterns were observed depending on size, number, and location of lesions. In early parenchymal involvement a ventilation-perfusion mismatch was seen. The initial and follow-up studies correlated well with clinical and radiographic findings. This noninvasive procedure is helpful in evaluating ventilatory and perfusion impairment in these patients as well as their response to treatment.

  8. COMPARISON OF ARTIFICIAL NEOCHORDAE AND NATIVE CHORDAL TRANSFER IN THE REPAIR OF A FLAIL POSTERIOR MITRAL LEAFLET: AN EXPERIMENTAL STUDY

    PubMed Central

    Padala, Muralidhar; Cardinau, Benedicte; Gyoneva, Lazarina I.; Thourani, Vinod H.

    2013-01-01

    BACKGROUND Surgical reconstruction of a flail posterior leaflet is a routine mitral valve repair, the techniques for which have evolved from leaflet resection to leaflet preservation. Artificial ePTFE neochordae are frequently used to stabilize the flail leaflet, and seldom translocation of the native secondary chordae of the valve to the leaflet free edge is used. In this study, we sought to investigate the efficacy of the two techniques to correct posterior leaflet prolapse and reduce mitral regurgitation, and quantify the acute post-repair leaflet kinematics. METHODS Adult porcine mitral valves (N =7) were studied in a pulsatile left heart experimental model in which isolated P2 flail was mimicked by marginal chordal transection. Baseline conditions were established in each valve under normal conditions (control), and followed by induction of isolated P2 flail by transecting the two marginal chordae on the posterior leaflet free edge (disease). The flail posterior leaflet was reconstructed using artificial neochordae (repair 1) and then native chordal translocation (repair 2). Reduction in leaflet flail, changes in mitral regurgitation fraction, leaflet coaptation length, and posterior leaflet mobility were measured using B-mode echocardiography or color doppler. RESULTS At baseline, all the valves were competent with no mitral regurgitation. After transection of the marginal chordae on the posterior leaflet, isolated P2 flail was evident with 13.7±13% regurgitation. Reconstruction with artificial neochordae eliminated leaflet flail and reduced mitral regurgitation to 3.2± 2.8%, and with chordal translocation leaflet flail was corrected and mitral regurgitation was measured at 2.3±2.6%. Using either repair techniques, leaflet coaptation and mobility of the repaired leaflets were adequate and comparable to the baseline measurements. CONCLUSIONS Comparable reduction leaflet flail and regurgitation, and restoration of physiological leaflet coaptation with the

  9. Behavior of Bilayer Leaflets in Asymmetric Model Membranes: Atomistic Simulation Studies

    SciTech Connect

    Tian, Jianhui; Nickels, Jonathan; Katsaras, John; Cheng, Xiaolin

    2016-04-27

    Spatial organization within lipid bilayers is an important feature for a range of biological processes. Leaflet compositional asymmetry and lateral lipid organization are just two of the ways in which membrane structure appears to be more complex than initially postulated by the fluid mosaic model. This raises the question of how the phase behavior in one bilayer leaflet may affect the apposing leaflet and how one begins to construct asymmetric model systems to investigate these interleaflet interactions. In this paper, we report on all-atom molecular dynamics simulations (a total of 4.1 μs) of symmetric and asymmetric bilayer systems composed of liquid-ordered (Lo) or liquid-disordered (Ld) leaflets, based on the nanodomain-forming POPC/DSPC/cholesterol system. We begin by analyzing an asymmetric bilayer with leaflets derived from simulations of symmetric Lo and Ld bilayers. In this system, we observe that the properties of the Lo and Ld leaflets are similar to those of the Lo and Ld leaflets in corresponding symmetric systems. However, it is not obvious that mixing the equilibrium structures of their symmetric counterparts is the most appropriate way to construct asymmetric bilayers nor that these structures will manifest interleaflet couplings that lead to domain registry/antiregistry. We therefore constructed and simulated four additional asymmetric bilayer systems by systematically adding or removing lipids in the Ld leaflet to mimic potential density fluctuations. We find that the number of lipids in the Ld leaflet affects its own properties, as well as those of the apposing Lo leaflet. Collectively, the simulations reveal the presence of weak acyl chain interdigitation across bilayer leaflets, suggesting that interdigitation alone does not contribute significantly to the interleaflet coupling in nonphase-separated bilayers of this chemical composition. Finally, however, the properties of both leaflets appear to be sensitive to changes in in-plane lipid

  10. Behavior of Bilayer Leaflets in Asymmetric Model Membranes: Atomistic Simulation Studies

    SciTech Connect

    Tian, Jianhui; Nickels, Jonathan; Katsaras, John; Cheng, Xiaolin

    2016-04-27

    Spatial organization within lipid bilayers is an important feature for a range of biological processes. Leaflet compositional asymmetry and lateral lipid organization are just two of the ways in which membrane structure appears to be more complex than initially postulated by the fluid mosaic model. This raises the question of how the phase behavior in one bilayer leaflet may affect the apposing leaflet and how one begins to construct asymmetric model systems to investigate these interleaflet interactions. In this paper, we report on all-atom molecular dynamics simulations (a total of 4.1 μs) of symmetric and asymmetric bilayer systems composed of liquid-ordered (Lo) or liquid-disordered (Ld) leaflets, based on the nanodomain-forming POPC/DSPC/cholesterol system. We begin by analyzing an asymmetric bilayer with leaflets derived from simulations of symmetric Lo and Ld bilayers. In this system, we observe that the properties of the Lo and Ld leaflets are similar to those of the Lo and Ld leaflets in corresponding symmetric systems. However, it is not obvious that mixing the equilibrium structures of their symmetric counterparts is the most appropriate way to construct asymmetric bilayers nor that these structures will manifest interleaflet couplings that lead to domain registry/antiregistry. We therefore constructed and simulated four additional asymmetric bilayer systems by systematically adding or removing lipids in the Ld leaflet to mimic potential density fluctuations. We find that the number of lipids in the Ld leaflet affects its own properties, as well as those of the apposing Lo leaflet. Collectively, the simulations reveal the presence of weak acyl chain interdigitation across bilayer leaflets, suggesting that interdigitation alone does not contribute significantly to the interleaflet coupling in nonphase-separated bilayers of this chemical composition. Finally, however, the properties of both leaflets appear to be sensitive to changes in in-plane lipid

  11. Therapeutic Vascular Compliance Change May Cause Significant Variation in Coronary Perfusion: A Numerical Study

    PubMed Central

    Nobari, S.; Mongrain, R.; Gaillard, E.; Leask, R.; Cartier, R.

    2012-01-01

    In some pathological conditions like aortic stiffening and calcific aortic stenosis (CAS), the microstructure of the aortic root and the aortic valve leaflets are altered in response to stress resulting in changes in tissue thickness, stiffness, or both. This aortic stiffening and CAS are thought to affect coronary blood flow. The goal of the present paper was to include the flow in the coronary ostia in the previous fluid structure interaction model we have developed and to analyze the effect of diseased tissues (aortic root stiffening and CAS) on coronary perfusion. Results revealed a significant impact on the coronary perfusion due to a moderate increase in the aortic wall stiffness and CAS (increase of the aortic valve leaflets thickness). A marked drop of coronary peak velocity occurred when the values of leaflet thickness and aortic wall stiffness were above a certain threshold, corresponding to a threefold of their normal value. Consequently, mild and prophylactic treatments such as smoking cessation, exercise, or diet, which have been proven to increase the aortic compliance, may significantly improve the coronary perfusion. PMID:22474538

  12. Displacement of the anterior leaflet of the tricuspid valve: Rare variant of Ebstein's anomaly.

    PubMed

    Tsujii, Nobuyuki; Kurosaki, Kenichi; Yasuda, Kenji; Mizuno, Masanori; Sakaguchi, Heima; Hoashi, Takaya; Ichikawa, Hajime; Shiraishi, Isao

    2016-08-01

    In Ebstein's anomaly, the points of attachment, or hinges, of the septal and mural leaflets in the right ventricle are displaced away from the atrioventricular junction. In contrast, the junctional hinge of the anterior leaflet usually retains a normal position. Here, we report a case of giant right atrial aneurysm due to isolated displacement of the anterior leaflet of the tricuspid valve in an infant, a rare variant of Ebstein's anomaly. Enlargement of the right atrium, which was initially diagnosed during the fetal period, progressively and markedly dilated after birth and was successfully treated with surgical resection. Isolated displacement of the anterior leaflet should be recognized as a variant of Ebstein's anomaly.

  13. Cryopreservation of porcine aortic heart valve leaflet-derived myofibroblasts.

    PubMed

    Campbell, L H; Brockbank, K G M

    2010-12-01

    Cryopreservation by freezing is usually employed for storage of allogeneic valves destined for clinical use; however, disruption of leaflet extracellular matrices by ice may occur. This study was performed to determine the effects of cryoprotectants employed in VS55 for ice-free, vitreous cryopreservation upon adherent porcine heart valve leaflet-derived myofibroblasts in culture. Low-passage myofibroblasts exhibiting strong actin and myosin staining were employed for these experiments. Three cryoprotectants, dimethylsulfoxide, formamide, and propanediol, were tested individually and in combination. Exposure experiments demonstrated that the individual cryoprotectants (0-5 M) were generally cytotoxic in a dose-dependent manner with little if any loss of cells as determined by measuring metabolic activity and DNA content. Exposure to formamide resulted in the greatest loss of cells and reduction in viability. Combination of the three cryoprotectants demonstrated that the cytotoxic effects of each cryoprotectant were not cumulative. Cell viability and DNA content were equivalent to dimethylsulfoxide and propanediol and higher than formamide alone over most of the 0-5 M dose-response curve. After cryopreservation by slow-rate freezing, the benefits of the combination of cryoprotectants over individual cryoprotectants were demonstrated at the 4 M concentration range for both cell viability and cell retention. In conclusion, these studies demonstrated that, with the exception of the lower concentrations of propanediol, the combination of cryoprotectants employed in these studies result in equivalent or better cell viability and attachment than individual cryoprotectants.

  14. Tri-layered elastomeric scaffolds for engineering heart valve leaflets

    PubMed Central

    Masoumi, Nafiseh; Annabi, Nasim; Assmann, Alexander; Larson, Benjamin L.; Hjortnaes, Jesper; Alemdar, Neslihan; Kharaziha, Mahshid; Manning, Keefe B.; Mayer, John E.; Khademhosseini, Ali

    2014-01-01

    Tissue engineered heart valves (TEHVs) that can grow and remodel have the potential to serve as permanent replacements of the current non-viable prosthetic valves particularly for pediatric patients. A major challenge in designing functional TEHVs is to mimic both structural and anisotropic mechanical characteristics of the native valve leaflets. To establish a more biomimetic model of TEHV, we fabricated tri-layered scaffolds by combining electrospinning and microfabrication techniques. These constructs were fabricated by assembling microfabricated poly(glycerol sebacate) (PGS) and fibrous PGS/poly(-caprolactone) (PCL) electrospun sheets to develop elastic scaffolds with tunable anisotropic mechanical properties similar to the mechanical characteristics of the native heart valves. The engineered scaffolds supported valvular interstitial cells (VICs) and mesenchymal stem cells (MSCs) growth within the 3D structure and promoted the deposition of heart valve extracellular matrix (ECM). MSCs were also organized and aligned along the anisotropic axes of the engineered tri-layered scaffolds. In addition, the fabricated constructs opened and closed properly in an ex vivo model of porcine heart valve leaflet tissue replacement. The engineered tri-layered scaffolds have the potential for successful translation towards TEHV replacements. PMID:24947233

  15. The Fluid Mechanics of Transcatheter Heart Valve Leaflet Thrombosis in the Neo-Sinus.

    PubMed

    Midha, Prem A; Raghav, Vrishank; Sharma, Rahul; Condado, Jose F; Okafor, Ikechukwu U; Rami, Tanya; Kumar, Gautam; Thourani, Vinod H; Jilaihawi, Hasan; Babaliaros, Vasilis; Makkar, Raj R; Yoganathan, Ajit P

    2017-07-19

    Background -Transcatheter heart valve (THV) thrombosis has been increasingly reported. In these studies, thrombus quantification has been based on 2D assessment of a 3D phenomenon. Methods -Post-procedural four-dimensional, volume-rendered CT (4DCT) data of CoreValve, Evolut R, and SAPIEN 3 transcatheter aortic valve replacement (TAVR) patients enrolled in the RESOLVE trial were included in this analysis. Patients on anticoagulation were excluded. SAPIEN 3 and CoreValve/Evolut R patients with and without hypo-attenuated leaflet thickening (HALT) were included in order to study differences between groups. Patients were classified as having THV thrombosis if there was any evidence of HALT. Anatomical and THV deployment geometries were analyzed, and thrombus volumes were computed through manual 3D reconstruction. We aimed to identify and evaluate risk factors that contribute to THV thrombosis through the combination of retrospective clinical data analysis and in vitro imaging in the space between the native and THV leaflets (neo-sinus). Results -SAPIEN 3 valves with leaflet thrombosis were on average 10% further expanded (by diameter) than those without (95.5 ± 5.2% vs. 85.4 ± 3.9%; p<0.001). However, this relationship was not evident with the CoreValve/Evolut R. In CoreValve/Evolut Rs with thrombosis, the thrombus volume increased linearly with implant depth (R(2) = 0.7; p < 0.001). This was not seen in the SAPIEN 3. The in vitro analysis showed that a supra-annular THV deployment resulted in a nearly 7-fold decrease in stagnation zone size (velocities less than 0.1 m/s) when compared to an intra-annular deployment. In addition, the in vitro model indicated that the size of the stagnation zone increased as cardiac output decreased. Conclusions -While TAVR thrombosis is a multi-factorial process involving foreign materials, patient-specific blood chemistry and complex flow patterns, our study indicates that deployed THV geometry may have implications on the

  16. [Consumer study on the use of patient information leaflets].

    PubMed

    Leemans, L; Heylen, N; Quanten, A; Deferme, S

    2011-12-01

    The aim of this study was to get a clear idea of the reading frequency of the patient information leaflet (PIL) and to set up a profile of the reader in specific. Apart from that, we also wanted to evaluate the impact of the internet in the patient's search for information on health and medication. Do patients consult the digital PIL and is the FAGG website known by common people? In order to answer these research questions, a specific inquiry was performed in 800 respondents. Some interesting conclusions can be drawn: only one out of four participants reads the full PIL when purchasing a medicine they never used before. People who always read the PIL are mainly older than 65. However, the largest amount of people who never reads the PIL is also situated in the plus 65 scale. In general, men show little interest in reading the PIL unlike woman, who read clearly more often the PIL. The parts of the PIL most often read by patients are the sections on dosage (section 3) and side effects (section 4). Unfortunately, too little attention is paid to the section 2, which contains the most warnings, such as contra-indications. The most important reason why the PIL is not read is because patients believe they get sufficient information from the doctor and the pharmacist. Another remark is that the internet is used by more than half of the respondents to search for health-related information. There is also a remarkable difference between men and woman, men rarely search for health information or information on medicines on the internet. The number of respondents searching for leaflets on the internet is quite limited. Additionally, the Federal Agency Medicines and Health Products (FAMHP) website is unknown to most internet users. We can conclude that the actual PIL is read too little. In order to make the PIL more appealing and even more patient friendly than it is actually, taking patients' needs into account should be a priority. The digital leaflet should be drawn

  17. CFD simulation of a novel bileaflet mechanical heart valve prosthesis: an estimation of the Venturi passage formed by the leaflets.

    PubMed

    Yokoyama, Y; Medart, D; Hormes, M; Schmitz, C; Hamilton, K; Kwant, P B; Takatani, S; Schmitz-Rode, T; Steinseifer, U

    2006-12-01

    The aim of this study was to validate the flow characteristics of the novel Helmholtz-Institute Aachen Bileaflet (HIA-BL) heart valve prosthesis. The curved leaflets of the HIA-BL valve form a Venturi passage between the leaflets at peak systole. By narrowing the cross section the flow accelerates and the static pressure at the central passage decreases according to the Venturi effect. The low-pressure zone between the leaflets is expected to stabilize the leaflets in fully open position at peak systole. To investigate the Venturi passage, the flow fields of two valve geometries were investigated by CFD (Computational Fluid Dynamics): one geometry exhibits curved leaflets resulting in a Venturi passage; the other geometry features straight leaflets. The flow profiles, pressure distribution and resulting torque of both passages were compared and investigated. Although flow profiles downstream of both valves were similar, the flow passages between the leaflets were different for the investigated leaflet geometries. The straight leaflet passage showed a large boundary layer separation zone near the leaflets and the lowest pressure at the leading edge of the leaflet. The Venturi passage showed a reduction of the boundary layer separation zones and the lowest pressure between the leaflets could be found in the narrowest flow cross section of the Venturi passage. Additionally, the resulting torque showed that the Venturi passage produced an opening momentum. The results demonstrate that the Venturi passage stabilizes the leaflets in open position at peak systole.

  18. Perfusion- and pattern-based quantitative CT indexes using contrast-enhanced dual-energy computed tomography in diffuse interstitial lung disease: relationships with physiologic impairment and prediction of prognosis.

    PubMed

    Moon, Jung Won; Bae, Jang Pyo; Lee, Ho Yun; Kim, Namkug; Chung, Man Pyo; Park, Hye Yun; Chang, Yongjun; Seo, Joon Beom; Lee, Kyung Soo

    2016-05-01

    To evaluate automated texture-based segmentation of dual-energy CT (DECT) images in diffuse interstitial lung disease (DILD) patients and prognostic stratification by overlapping morphologic and perfusion information of total lung. Suspected DILD patients scheduled for surgical biopsy were prospectively included. Texture patterns included ground-glass opacity (GGO), reticulation and consolidation. Pattern- and perfusion-based CT measurements were assessed to extract quantitative parameters. Accuracy of texture-based segmentation was analysed. Correlations between CT measurements and pulmonary function test or 6-minute walk test (6MWT) were calculated. Parameters of idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) and non-IPF/UIP were compared. Survival analysis was performed. Overall accuracy was 90.47% for whole lung segmentation. Correlations between mean iodine values of total lung, 50-97.5th (%) attenuation and forced vital capacity or 6MWT were significant. Volume of GGO, reticulation and consolidation had significant correlation with DLco or SpO2 on 6MWT. Significant differences were noted between IPF/UIP and non-IPF/UIP in 6MWT distance, mean iodine value of total lung, 25-75th (%) attenuation and entropy. IPF/UIP diagnosis, GGO ratio, DILD extent, 25-75th (%) attenuation and SpO2 on 6MWT showed significant correlations with survival. DECT combined with pattern analysis is useful for analysing DILD and predicting survival by provision of morphology and enhancement. • Dual-energy CT (DECT) produces morphologic and parenchymal enhancement information. • Automated lung segmentation enables analysis of disease extent and severity. • This prospective study showed value of DECT in DILD patients. • Parameters on DECT enable characterization and survival prediction of DILD.

  19. Saddle-shaped mitral valve annuloplasty rings improve leaflet coaptation geometry

    PubMed Central

    Jensen, Morten O.; Jensen, Henrik; Levine, Robert A.; Yoganathan, Ajit P.; Andersen, Niels Trolle; Nygaard, Hans; Hasenkam, J. Michael; Nielsen, Sten L.

    2011-01-01

    Objectives The mitral valve annulus naturally conforms to a saddle shape in systole. This configuration is believed to put the leaflets into a lower-energy equilibrium with the annulus and subvalvular apparatus. Conventional flat annuloplasty rings restrict posterior leaflet motion, which may result in a “monocusp” valve, affecting valvular stress distribution. It is hypothesized that saddle-shaped annuloplasty rings cause less distortion of the physiologic leaflet geometry than do flat rings. Methods Twelve pigs were studied in an acute setting with 3-dimensional echocardiography and sonomicrometry before and after implantation of rigid flat (n = 5) and saddle-shaped (n = 7) annuloplasty rings. The rings were true sized to the annulus with equal anterior–posterior and commissure–commissure circumferential dimensions. The saddle-shaped rings had an annular height to commissural width ratio of 15%. Results Saddle-shaped rings maintained both leaflets operational (P <.01). Flat rings made the posterior leaflet immobile and the anterior leaflet aligned flat along the annulus in systole, effectively resulting in monoleaflet function. The average distance from the papillary muscle tips to the posterior annulus decreased by 2.4 ± 0.4 mm after flat ring implantation (P <.01). Conclusions Saddle-shaped annuloplasty rings provide better leaflet coaptation geometry than do flat rings by not hoisting the papillary muscles toward the posterior annulus through the commissural chordae, allowing greater leaflet mobility. This entails a potentially beneficial impact on valvular stress distribution that could affect durability of the repaired valve. PMID:21329946

  20. Effect of the Mitral Valve's Anterior Leaflet on Axisymmetry of Transmitral Vortex Ring.

    PubMed

    Falahatpisheh, Ahmad; Pahlevan, Niema M; Kheradvar, Arash

    2015-10-01

    The shape and formation of transmitral vortex ring are shown to be associated with diastolic function of the left ventricle (LV). Transmitral vortex ring is a flow feature that is observed to be non-axisymmetric in a healthy heart and its inherent asymmetry in the LV assists in efficient ejection of the blood during systole. This study is a first step towards understanding the effects of the mitral valve's anterior leaflet on transmitral flow. We experimentally study a single-leaflet model of the mitral valve to investigate the effect of the anterior leaflet on the axisymmetry of the generated vortex ring based on the three-dimensional data acquired using defocusing digital particle image velocimetry. Vortex rings form downstream of a D-shaped orifice in presence or absence of the anterior leaflet in various physiological stroke ratios. The results of the statistical analysis indicate that the formed vortex ring downstream of a D-shaped orifice is markedly non-axisymmetric, and presence of the anterior leaflet improves the ring's axisymmetry. This study suggests that the improvement of axisymmetry in presence of the anterior leaflet might be due to coupled dynamic interaction between rolling-up of the shear layer at the edges of the D-shaped orifice and the borders of the anterior leaflet. This interaction can reduce the non-uniformity in vorticity generation, which results in more axisymmetric behavior compared to the D-shaped orifice without the anterior leaflet.

  1. Readability Statistics of Patient Information Leaflets in a Speech and Language Therapy Department

    ERIC Educational Resources Information Center

    Pothier, Louise; Day, Rachael; Harris, Catherine; Pothier, David D.

    2008-01-01

    Background: Information leaflets are commonly used in Speech and Language Therapy Departments. Despite widespread use, they can be of variable quality. Aims: To revise current departmental leaflets using the National Health Service (NHS) Toolkit for Producing Patient Information and to test the effect that this has on the readability scores of the…

  2. Readability Statistics of Patient Information Leaflets in a Speech and Language Therapy Department

    ERIC Educational Resources Information Center

    Pothier, Louise; Day, Rachael; Harris, Catherine; Pothier, David D.

    2008-01-01

    Background: Information leaflets are commonly used in Speech and Language Therapy Departments. Despite widespread use, they can be of variable quality. Aims: To revise current departmental leaflets using the National Health Service (NHS) Toolkit for Producing Patient Information and to test the effect that this has on the readability scores of the…

  3. Preparation, validation and user-testing of pictogram-based patient information leaflets for hemodialysis patients.

    PubMed

    Mateti, Uday Venkat; Nagappa, Anantha Naik; Attur, Ravindra Prabhu; Bairy, Manohar; Nagaraju, Shankar Prasad; Mallayasamy, Surulivelrajan; Vilakkathala, Rajesh; Guddattu, Vasudev; Balkrishnan, Rajesh

    2015-11-01

    Patient information leaflets are universally-accepted resources to educate the patients/users about their medications, disease and lifestyle modification. The objective of the study was to prepare, validate and perform user-testing of pictogram-based patient information leaflets (P-PILs) among hemodialysis (HD) patients. The P-PILs are prepared by referring to the primary, secondary and tertiary resources. The content and pictograms of the leaflet have been validated by an expert committee consisting of three nephrologists and two academic pharmacists. The Baker Able Leaflet Design has been applied to develop the layout and design of the P-PILs. Quasi-experimental pre- and post-test design without control group was conducted on 81 HD patients for user-testing of P-PILs. The mean Baker Able Leaflet Design assessment score for English version of the leaflet was 28, and 26 for Kannada version. The overall user-testing knowledge assessment mean scores were observed to have significantly improved from 44.25 to 69.62 with p value <0.001. The overall user opinion of content and legibility of the leaflets was good. Pictogram-based patient information leaflets can be considered an effective educational tool for HD patients.

  4. Cochlear perfusion with a viscous fluid.

    PubMed

    Wang, Yi; Olson, Elizabeth S

    2016-07-01

    then clearance of viscous fluid within the cochlea, or to a temporary position shift of the Organ of Corti. After 0.5% HA perfusion, a short latency positive peak (P0) appeared in the CAP waveform. This P0 might be due to a change in the cochlea's traveling-wave pattern, or distortion in the cochlear microphonic.

  5. Cochlear perfusion with a viscous fluid

    PubMed Central

    Wang, Yi; Olson, Elizabeth S.

    2016-01-01

    , perhaps due to the presence and then clearance of viscous fluid within the cochlea, or to a temporary position shift of the Organ of Corti. After 0.5% HA perfusion, a short latency positive peak (P0) appeared in the CAP wavefrom. This P0 might be due to a change in the cochlea’s traveling-wave pattern, or distortion in the cochlear microphonic. PMID:27220484

  6. High-Resolution Fluid–Structure Interaction Simulations of Flow Through a Bi-Leaflet Mechanical Heart Valve in an Anatomic Aorta

    PubMed Central

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2011-01-01

    We have performed high-resolution fluid–structure interaction simulations of physiologic pulsatile flow through a bi-leaflet mechanical heart valve (BMHV) in an anatomically realistic aorta. The results are compared with numerical simulations of the flow through an identical BMHV implanted in a straight aorta. The comparisons show that although some of the salient features of the flow remain the same, the aorta geometry can have a major effect on both the flow patterns and the motion of the valve leaflets. For the studied configuration, for instance, the BMHV leaflets in the anatomic aorta open much faster and undergo a greater rebound during closing than the same valve in the straight axisymmetric aorta. Even though the characteristic triple-jet structure does emerge downstream of the leaflets for both cases, for the anatomic case the leaflet jets spread laterally and diffuse much faster than in the straight aorta due to the aortic curvature and complex shape of the anatomic sinus. Consequently the leaflet shear layers in the anatomic case remain laminar and organized for a larger portion of the accelerating phase as compared to the shear layers in the straight aorta, which begin to undergo laminar instabilities well before peak systole is reached. For both cases, however, the flow undergoes a very similar explosive transition to the small-scale, turbulent-like state just prior to reaching peak systole. The local maximum shear stress is used as a metric to characterize the mechanical environment experienced by blood cells. Pockets of high local maximum shear are found to be significantly more widespread in the anatomic aorta than in the straight aorta throughout the cardiac cycle. Pockets of high local maximum shear were located near the leaflets and in the aortic arc region. This work clearly demonstrates the importance of the aortic geometry on the flow phenomena in a BMHV and demonstrates the potential of our computational method to carry out image

  7. High-resolution fluid-structure interaction simulations of flow through a bi-leaflet mechanical heart valve in an anatomic aorta.

    PubMed

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2010-02-01

    We have performed high-resolution fluid-structure interaction simulations of physiologic pulsatile flow through a bi-leaflet mechanical heart valve (BMHV) in an anatomically realistic aorta. The results are compared with numerical simulations of the flow through an identical BMHV implanted in a straight aorta. The comparisons show that although some of the salient features of the flow remain the same, the aorta geometry can have a major effect on both the flow patterns and the motion of the valve leaflets. For the studied configuration, for instance, the BMHV leaflets in the anatomic aorta open much faster and undergo a greater rebound during closing than the same valve in the straight axisymmetric aorta. Even though the characteristic triple-jet structure does emerge downstream of the leaflets for both cases, for the anatomic case the leaflet jets spread laterally and diffuse much faster than in the straight aorta due to the aortic curvature and complex shape of the anatomic sinus. Consequently the leaflet shear layers in the anatomic case remain laminar and organized for a larger portion of the accelerating phase as compared to the shear layers in the straight aorta, which begin to undergo laminar instabilities well before peak systole is reached. For both cases, however, the flow undergoes a very similar explosive transition to the small-scale, turbulent-like state just prior to reaching peak systole. The local maximum shear stress is used as a metric to characterize the mechanical environment experienced by blood cells. Pockets of high local maximum shear are found to be significantly more widespread in the anatomic aorta than in the straight aorta throughout the cardiac cycle. Pockets of high local maximum shear were located near the leaflets and in the aortic arc region. This work clearly demonstrates the importance of the aortic geometry on the flow phenomena in a BMHV and demonstrates the potential of our computational method to carry out image

  8. Altered myocardial glucose utilization and the reverse mismatch pattern on rubidium-82 perfusion/F-18-FDG PET during the sub-acute phase following reperfusion of acute anterior myocardial infarction.

    PubMed

    Anselm, Daniel D; Anselm, Anjali H; Renaud, Jennifer; Atkins, Harold L; de Kemp, Robert; Burwash, Ian G; Williams, Kathryn A; Guo, Ann; Kelly, Cathy; Dasilva, Jean; Beanlands, Rob S B; Glover, Christopher A

    2011-08-01

    Reperfused myocardium post-acute myocardial infarction (AMI) may have altered metabolism with implications for therapy response and function recovery. We explored glucose utilization and the "reverse mismatch" (RMM) pattern (decreased F-18-fluorodeoxyglucose (FDG) uptake relative to perfusion) in patients who underwent mechanical reperfusion with percutaneous coronary intervention (PCI) for AMI. Thirty-one patients with anterior wall AMI treated with acute reperfusion, with left ventricular ejection fraction ≤45%, underwent rest rubidium-82 (Rb-82) and FDG PET 2-10 days post-AMI. Resting echocardiograms were used to assess wall motion abnormalities. Significant RMM occurred in 15 (48%) patients and was associated with a shorter time to PCI of 2.9 hours (2.2, 13.3 hours) compared to patients without significant RMM: 11.4 hours (3.9, 22.4 hours) (P = .03). Within the peri-infarct regions, segments with significant RMM were more likely to have wall motion abnormalities (OR = 2.3 (1.1, 4.7), P = .02) compared to segments without significant RMM. RMM is a common pattern on perfusion/FDG PET during the sub-acute phase following reperfusion of AMI and is associated with shorter times to PCI. Within the peri-infarct region, RMM occurs frequently and is more often associated with wall motion abnormalities than segments without RMM. Whether this represents a myocardial metabolic shift during the sub-acute phase of recovery warrants further study.

  9. Perfusion visualization and analysis for pulmonary embolism

    NASA Astrophysics Data System (ADS)

    Vaz, Michael S.; Kiraly, Atilla P.; Naidich, David P.; Novak, Carol L.

    2005-04-01

    Given the nature of pulmonary embolism (PE), timely and accurate diagnosis is critical. Contrast enhanced high-resolution CT images allow physicians to accurately identify segmental and sub-segmental emboli. However, it is also important to assess the effect of such emboli on the blood flow in the lungs. Expanding upon previous research, we propose a method for 3D visualization of lung perfusion. The proposed method allows users to examine perfusion throughout the entire lung volume at a single glance, with areas of diminished perfusion highlighted so that they are visible independent of the viewing location. This may be particularly valuable for better accuracy in assessing the extent of hemodynamic alterations resulting from pulmonary emboli. The method also facilitates user interaction and may help identify small peripheral sub-segmental emboli otherwise overlooked. 19 patients referred for possible PE were evaluated by CT following the administration of IV contrast media. An experienced thoracic radiologist assessed the 19 datasets with 17 diagnosed as being positive for PE with multiple emboli. Since anomalies in lung perfusion due to PE can alter the distribution of parenchymal densities, we analyzed features collected from histograms of the computed perfusion maps and demonstrate their potential usefulness as a preliminary test to suggest the presence of PE. These histogram features also offer the possibility of distinguishing distinct patterns associated with chronic PE and may even be useful for further characterization of changes in perfusion or overall density resulting from associated conditions such as pneumonia or diffuse lung disease.

  10. Tuning lipid mixtures to induce or suppress domain formation across leaflets of unsupported asymmetric bilayers.

    PubMed

    Collins, Marcus D; Keller, Sarah L

    2008-01-08

    Plasma membranes of cells are asymmetric in both lipid and protein composition. The mechanism by which proteins on both sides of the membrane colocalize during signaling events is unknown but may be due to the induction of inner leaflet domains by the outer leaflet. Here we show that liquid domains form in asymmetric Montal-Mueller planar bilayers in which one leaflet's composition would phase-separate in a symmetric bilayer and the other's would not. Equally important, by tuning the lipid composition of the second leaflet, we are able to suppress domains in the first leaflet. When domains are present in asymmetric membranes, each leaflet contains regions of three distinct lipid compositions, implying strong interleaflet interactions. Our results show that mechanisms of domain induction between the outer and inner leaflets of cell plasma membranes do not necessarily require the participation of membrane proteins. Based on these findings, we suggest mechanisms by which cells could actively regulate protein function by modulating local lipid composition or interleaflet interactions.

  11. Differential Stiffness and Lipid Mobility in the Leaflets of Purple Membranes

    PubMed Central

    Voïtchovsky, Kislon; Antoranz Contera, Sonia; Kamihira, Miya; Watts, Anthony; Ryan, J. F.

    2006-01-01

    Purple membranes (PM) are two-dimensional crystals formed by bacteriorhodopsin and a variety of lipids. The lipid composition and density in the cytoplasmic (CP) leaflet differ from those of the extracellular (EC) leaflet. A new way of differentiating the two sides of such asymmetric membranes using the phase signal in alternate contact atomic force microscopy is presented. This method does not require molecular resolution and is applied to study the stiffness and intertrimer lipid mobility in both leaflets of the PM independently over a broad range of pH and salt concentrations. PM stiffens with increasing salt concentration according to two different regimes. At low salt concentration, the membrane Young's normal modulus grows quickly but differentially for the EC and CP leaflets. At higher salt concentration, both leaflets behave similarly and their stiffness converges toward the native environment value. Changes in pH do not affect PM stiffness; however, the crystal assembly is less pronounced at pH ≥ 10. Lipid mobility is high in the CP leaflet, especially at low salt concentration, but negligible in the EC leaflet regardless of pH or salt concentration. An independent lipid mobility study by solid-state NMR confirms and quantifies the atomic force microscopy qualitative observations. PMID:16387758

  12. Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets.

    PubMed

    Brunschwig, Christel; Leba, Louis-Jérôme; Saout, Mona; Martial, Karine; Bereau, Didier; Robinson, Jean-Charles

    2016-12-29

    Euterpe oleracea (açaí) is a palm tree well known for the high antioxidant activity of its berries used as dietary supplements. Little is known about the biological activity and the composition of its vegetative organs. The objective of this study was to investigate the antioxidant activity of root and leaflet extracts of Euterpe oleracea (E. oleracea) and characterize their phytochemicals. E. oleracea roots and leaflets extracts were screened in different chemical antioxidant assays (DPPH-2,2-diphenyl-1-picrylhydrazyl, FRAP-ferric feducing antioxidant power, and ORAC-oxygen radical absorbance capacity), in a DNA nicking assay and in a cellular antioxidant activity assay. Their polyphenolic profiles were determined by UV and LC-MS/MS. E. oleracea leaflets had higher antioxidant activity than E. oleracea berries, and leaflets of Oenocarpus bacaba and Oenocarpus bataua, as well as similar antioxidant activity to green tea. E. oleracea leaflet extracts were more complex than root extracts, with fourteen compounds, including caffeoylquinic acids and C-glycosyl derivatives of apigenin and luteolin. In the roots, six caffeoylquinic and caffeoylshikimic acids were identified. Qualitative compositions of E. oleracea, Oenocarpus bacaba and Oenocarpus bataua leaflets were quite similar, whereas the quantitative compositions were quite different. These results provide new prospects for the valorization of roots and leaflets of E. oleracea in the pharmaceutical, food or cosmetic industry, as they are currently by-products of the açaí industry.

  13. Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets

    PubMed Central

    Brunschwig, Christel; Leba, Louis-Jérôme; Saout, Mona; Martial, Karine; Bereau, Didier; Robinson, Jean-Charles

    2016-01-01

    Euterpe oleracea (açaí) is a palm tree well known for the high antioxidant activity of its berries used as dietary supplements. Little is known about the biological activity and the composition of its vegetative organs. The objective of this study was to investigate the antioxidant activity of root and leaflet extracts of Euterpe oleracea (E. oleracea) and characterize their phytochemicals. E. oleracea roots and leaflets extracts were screened in different chemical antioxidant assays (DPPH—2,2-diphenyl-1-picrylhydrazyl, FRAP—ferric feducing antioxidant power, and ORAC—oxygen radical absorbance capacity), in a DNA nicking assay and in a cellular antioxidant activity assay. Their polyphenolic profiles were determined by UV and LC-MS/MS. E. oleracea leaflets had higher antioxidant activity than E. oleracea berries, and leaflets of Oenocarpus bacaba and Oenocarpus bataua, as well as similar antioxidant activity to green tea. E. oleracea leaflet extracts were more complex than root extracts, with fourteen compounds, including caffeoylquinic acids and C-glycosyl derivatives of apigenin and luteolin. In the roots, six caffeoylquinic and caffeoylshikimic acids were identified. Qualitative compositions of E. oleracea, Oenocarpus bacaba and Oenocarpus bataua leaflets were quite similar, whereas the quantitative compositions were quite different. These results provide new prospects for the valorization of roots and leaflets of E. oleracea in the pharmaceutical, food or cosmetic industry, as they are currently by-products of the açaí industry. PMID:28036089

  14. Transcatheter Valve Underexpansion Limits Leaflet Durability: Implications for Valve-in-Valve Procedures.

    PubMed

    Martin, Caitlin; Sun, Wei

    2017-02-01

    Transcatheter aortic valve (TAV) implantation within a failed bioprosthetic valve is a growing trend for high-risk patients. The non-compliant stent of the previous prosthesis may prevent full expansion of the TAV, which has been shown to distort the leaflet configuration, and has been hypothesized to adversely affect durability. In this study, TAV leaflet fatigue damage under cyclic pressurization in the setting of stent underexpansion by 0 (fully expanded), 1, 2 and 3 mm was simulated using finite element analysis to test this hypothesis. In the 2 and 3 mm underexpanded devices, the TAV leaflets exhibited severe pin-wheeling during valve closure, which increased leaflet stresses dramatically, and resulted in accelerated fatigue damage of the leaflets. The leaflet fatigue damage in the 1 mm underexpanded case was similar to that in the fully expanded case. Clinically a range of 10-15% underexpansion is generally considered acceptable; however, it was observed in this study that ≥2 mm (≥9.1%) underexpansion, will significantly impact device durability. Further study is necessary to determine the impact of various deployment conditions, i.e. non-uniform and non-circular deployments and different implantation heights, on differing TAV devices, but it is clear that the normal TAV leaflet configuration must be preserved in order to preserve durability.

  15. Developing leaflets to give dental health advice to Aboriginal families with young children.

    PubMed

    Blinkhorn, Fiona; Wallace, Janet; Smith, Leanne; Blinkhorn, Anthony S

    2014-08-01

    Dental caries (decay) is a serious problem for young Aboriginal children, causing pain and stress. Treatment often involves extraction of teeth under a general anaesthetic. However, dental caries can be prevented by reducing the frequency of sugar consumption and brushing teeth twice a day with fluoride toothpaste. Such straightforward advice could be given to families by Aboriginal Health Workers who are trusted by their communities and have an existing advisory role. This paper reports on the development of dental health advice leaflets for use in Aboriginal communities. An Aboriginal reference panel was recruited to comment on dental health advice leaflets prepared by an Aboriginal graphic designer. The panel was asked to consider the design, cultural appropriateness and practicality of the leaflets. Comments were collected through email and face-to-face discussions, which were collated and the leaflets altered accordingly. The advice from the panel resulted in greater use of pictures. For example large green ticks and red crosses highlighted healthy and unhealthy behaviours, respectively. The tooth brushing leaflet was amended to emphasise the safe storage of toothpaste in order to keep it out of reach of young children. The panel stated that all leaflets should incorporate the Aboriginal flag, and proposed that fridge magnets might be beneficial as all family members would benefit from seeing the messages every day. The consultation process refined dental advice leaflets to reflect the views of an Aboriginal Reference Panel, in terms of design, cultural competence and practicality. © 2014 FDI World Dental Federation.

  16. A biomimetic bi-leaflet mitral prosthesis with enhanced physiological left ventricular swirl restorative capability

    NASA Astrophysics Data System (ADS)

    Tan, Sean Guo-Dong; Kim, Sangho; Leo, Hwa Liang

    2016-06-01

    Mechanical heart valve prostheses are often implanted in young patients due to their durability and long-term reliability. However, existing designs are known to induce elevated levels of blood damage and blood platelet activation. As a result, there is a need for patients to undergo chronic anti-coagulation treatment to prevent thrombosis, often resulting in bleeding complications. Furthermore, recent studies have suggested that the implantation of a mechanical prosthetic valve at the mitral position results in a significant alteration of the left ventricular flow field which may contribute to flow turbulence. This study proposes a bi-leaflet mechanical heart valve design (Bio-MHV) that mimics the geometry of a human mitral valve, with the aim of reducing turbulence levels in the left ventricle by replicating physiological flow patterns. An in vitro three-dimensional particle velocimetry imaging experiment was carried out to compare the hemodynamic performance of the Bio-MHV with that of the clinically established ATS valve. The Bio-MHV was found to replicate physiological left ventricular flow patterns and produced lower turbulence levels.

  17. Behavior of Bilayer Leaflets in Asymmetric Model Membranes: Atomistic Simulation Studies

    DOE PAGES

    Tian, Jianhui; Nickels, Jonathan; Katsaras, John; ...

    2016-04-27

    Spatial organization within lipid bilayers is an important feature for a range of biological processes. Leaflet compositional asymmetry and lateral lipid organization are just two of the ways in which membrane structure appears to be more complex than initially postulated by the fluid mosaic model. This raises the question of how the phase behavior in one bilayer leaflet may affect the apposing leaflet and how one begins to construct asymmetric model systems to investigate these interleaflet interactions. In this paper, we report on all-atom molecular dynamics simulations (a total of 4.1 μs) of symmetric and asymmetric bilayer systems composed ofmore » liquid-ordered (Lo) or liquid-disordered (Ld) leaflets, based on the nanodomain-forming POPC/DSPC/cholesterol system. We begin by analyzing an asymmetric bilayer with leaflets derived from simulations of symmetric Lo and Ld bilayers. In this system, we observe that the properties of the Lo and Ld leaflets are similar to those of the Lo and Ld leaflets in corresponding symmetric systems. However, it is not obvious that mixing the equilibrium structures of their symmetric counterparts is the most appropriate way to construct asymmetric bilayers nor that these structures will manifest interleaflet couplings that lead to domain registry/antiregistry. We therefore constructed and simulated four additional asymmetric bilayer systems by systematically adding or removing lipids in the Ld leaflet to mimic potential density fluctuations. We find that the number of lipids in the Ld leaflet affects its own properties, as well as those of the apposing Lo leaflet. Collectively, the simulations reveal the presence of weak acyl chain interdigitation across bilayer leaflets, suggesting that interdigitation alone does not contribute significantly to the interleaflet coupling in nonphase-separated bilayers of this chemical composition. Finally, however, the properties of both leaflets appear to be sensitive to changes in in

  18. [Development and evaluation of an information leaflet for patients consulting an university hospital dental clinic].

    PubMed

    Pegon-Machat, E; Tubert-Jeannin, S

    2010-04-01

    Dental clinics in university hospitals have several roles; dental care is delivered to patients while dental students learn clinical practice. Patients are subjected thus to specific constraints in those mixed hospital-university structures. Patients should be informed of how these structures work and their consent must be carefully sought. Otherwise, patients could manifest their refusal to receive care by interrupting the treatment process. This study was aimed to develop an information leaflet about the organisation of the dental clinic of the university hospital of Clermont-Ferrand. A quasi-randomised controlled study was conducted to evaluate the impact of this leaflet on patients' knowledge and absenteeism. The types of information to be included in the leaflet were determined using focus groups with patients, students and practitioners. The design, appropriateness and clarity of the leaflet were pilot tested among 30 patients. The evaluation of the impact of the leaflet was conducted among new patients who visited the dental clinic in 2007-2008. Patients were randomly allocated to three groups; one group (G1) received the leaflet at home by mail before the first visit, one group (G2) benefited from the leaflet during the first visit and one group (G3) did not receive the leaflet. The number of patients present at their appointment was recorded during the first visit (G1, G2, G3) and the second one (G2, G3). The knowledge of the patients about the dental clinic was evaluated by using a self-administered questionnaire before (except G1) and after reading the leaflet. The study population included 269 patients; 94 answered the two successive questionnaires (G1=32, G2=30, G3=31). At baseline, patients did not have sufficient knowledge about the way the dental clinic was functioning. The leaflet partly improved the level of knowledge of the patients when it was given during the first visit. About 25 % of the patients were not present at their appointment and this

  19. Abdominal perfusion computed tomography.

    PubMed

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-02-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis.

  20. Abdominal Perfusion Computed Tomography

    PubMed Central

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M. Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-01-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis. PMID:25610249

  1. A framework for the evaluation of patient information leaflets.

    PubMed

    Garner, Mark; Ning, Zhenye; Francis, Jill

    2012-09-01

      The provision of patient information leaflets (PILs) is an important part of health care. PILs require evaluation, but the frameworks that are used for evaluation are largely under-informed by theory. Most evaluation to date has been based on indices of readability, yet several writers argue that readability is not enough. We propose a framework for evaluating PILs that reflect the central role of the patient perspective in communication and use methods for evaluation based on simple linguistic principles.   The framework has three elements that give rise to three approaches to evaluation. Each element is a necessary but not sufficient condition for effective communication. Readability (focussing on text) may be assessed using existing well-established procedures. Comprehensibility (focussing on reader and text) may be assessed using multiple-choice questions based on the lexical and semantic features of the text. Communicative effectiveness (focussing on reader) explores the relationship between the emotional, cognitive and behavioural responses of the reader and the objectives of the PIL. Suggested methods for assessment are described, based on our preliminary empirical investigations.   The tripartite model of communicative effectiveness is a patient-centred framework for evaluating PILs. It may assist the field in moving beyond readability to broader indicators of the quality and appropriateness of printed information provided to patients. © 2011 Blackwell Publishing Ltd.

  2. Mechanical properties of elastomers for artificial leaflet heart valves

    NASA Astrophysics Data System (ADS)

    Parfeev, V. M.; Grushetskii, I. V.; Smurova, E. V.

    1983-01-01

    Biaxial tension is the usual type of stress on prosthesis parts made from polymer sheets. The chemical characteristics of medical elastomers in static and cyclic biaxial tension are poorer than in monaxial tension. These indices may be used for a realistic evaluation of the feasibility of using a given material for prostheses. Biaxial tension produced by a punch in conjunction with light transmission measurements may yield information on the production process and the condition of the material. Static and cyclic liquid pressure measurements are irreplaceable for medical elastomers and products, since they reveal the specific mechanisms for rupture, which may not be noted using other types of stressing. This study revealed the danger zones for leaflet AHV and provides sufficient methods for mechanical testing. In the future, the design of prostheses should be improved by placing major attention on the zones of cusp attachment. The mechanical testing results indicated that isotropic silicone and fluorosilicone rubbers may be used in valve prostheses for the pulmonary artery. Aortic valve prostheses should be made with reinforced rubber and polyurethane.

  3. A framework for the evaluation of patient information leaflets

    PubMed Central

    Garner, Mark; Ning, Zhenye; Francis, Jill

    2011-01-01

    Abstract Background  The provision of patient information leaflets (PILs) is an important part of health care. PILs require evaluation, but the frameworks that are used for evaluation are largely under‐informed by theory. Most evaluation to date has been based on indices of readability, yet several writers argue that readability is not enough. We propose a framework for evaluating PILs that reflect the central role of the patient perspective in communication and use methods for evaluation based on simple linguistic principles. The proposed framework  The framework has three elements that give rise to three approaches to evaluation. Each element is a necessary but not sufficient condition for effective communication. Readability (focussing on text) may be assessed using existing well‐established procedures. Comprehensibility (focussing on reader and text) may be assessed using multiple‐choice questions based on the lexical and semantic features of the text. Communicative effectiveness (focussing on reader) explores the relationship between the emotional, cognitive and behavioural responses of the reader and the objectives of the PIL. Suggested methods for assessment are described, based on our preliminary empirical investigations. Conclusions  The tripartite model of communicative effectiveness is a patient‐centred framework for evaluating PILs. It may assist the field in moving beyond readability to broader indicators of the quality and appropriateness of printed information provided to patients. PMID:21332620

  4. [Instrumental, directive, and affective communication in hospital leaflets].

    PubMed

    Vasconcellos-Silva, Paulo Roberto; Uribe Rivera, Francisco Javier; Castiel, Luis David

    2003-01-01

    This study focuses on the typical semantic systems extracted from hospital staff communicative resources which attempt to validate information as an "object" to be transferred to patients. We describe the models of textual communication in 58 patient information leaflets from five hospital units in Brazil, gathered from 1996 to 2002. Three categories were identified, based on the theory of speech acts (Austin, Searle, and Habermas): 1) cognitive-instrumental utterances: descriptions by means of technical terms validated by self-referred, incomplete, or inaccessible argumentation, with an implicit educational function; 2) technical-directive utterances: self-referred (to the context of the source domains), with a shifting of everyday acts to a technical terrain with a disciplinary function and impersonal features; and 3) expressive modulations: need for inter-subjective connections to strengthen bonds of trust and a tendency to use childish arguments. We conclude that the three categories displayed: fragmentary sources; assumption of univocal messages and invariable use of information (idealized motivations and interests, apart from individualized perspectives); and assumption of universal interests as generators of knowledge.

  5. The susceptibility of bioprosthetic heart valve leaflets to oxidation.

    PubMed

    Christian, Abigail J; Lin, Hongqiao; Alferiev, Ivan S; Connolly, Jeanne M; Ferrari, Giovanni; Hazen, Stanley L; Ischiropoulos, Harry; Levy, Robert J

    2014-02-01

    The clinical use of bioprosthetic heart valves (BHV) is limited due to device failure caused by structural degeneration of BHV leaflets. In this study we investigated the hypothesis that oxidative stress contributes to this process. Fifteen clinical BHV that had been removed for device failure were analyzed for oxidized amino acids using mass spectrometry. Significantly increased levels of ortho-tyrosine, meta-tyrosine and dityrosine were present in clinical BHV explants as compared to the non-implanted BHV material glutaraldehyde treated bovine pericardium (BP). BP was exposed in vitro to oxidizing conditions (FeSO4/H2O2) to assess the effects of oxidation on structural degeneration. Exposure to oxidizing conditions resulted in significant collagen deterioration, loss of glutaraldehyde cross-links, and increased susceptibility to collagenase degradation. BP modified through covalent attachment of the oxidant scavenger 3-(4-hydroxy-3,5-di-tert-butylphenyl) propyl amine (DBP) was resistant to all of the monitored parameters of structural damage induced by oxidation. These results indicate that oxidative stress, particularly via hydroxyl radical and tyrosyl radical mediated pathways, may be involved in the structural degeneration of BHV, and that this mechanism may be attenuated through local delivery of antioxidants such as DBP. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. [Consensus on the legibility criteria of health education leaflets].

    PubMed

    Barrio-Cantalejo, I; Simón-Lorda, P; Jiménez, M Melguizo; Ruiz, A Molina

    2011-01-01

    To identify the most relevant aspects that guarantee the readability, clarity and simplicity of written health education materials. Delphi methodology in order to reach a state of consensus among health education experts on criteria of legibility in the design and publication of informative material and literature. Seventeen experts reached agreement on the principal recommendations for ensuring the legibility of health education materials. They were as follows: a) text content and layout: to structure the text using a title or subtitle, message explanation and conclusion; b) text construction: to use simple and concise sentences, diagrams and examples, and graphically highlighting the principal ideas; c) lexical comprehension: to use simple words and avoid technical language and abbreviations; d) typography: to use an easy-to-read font. There is a high degree of consensus regarding the way health education materials should be drawn up. This list of recommendations could be used as an instrument for reviewing and improving the design of health education materials. In general, it is recommended to identify the users of the leaflets and involve them in the writing and design.

  7. Dutch perfusion incident survey.

    PubMed

    Groenenberg, Ingrid; Weerwind, Patrick W; Everts, Peter A M; Maessen, Jos G

    2010-09-01

    Cardiopulmonary bypass procedures remain complex, involving many potential risks. Therefore, a nationwide retrospective study was conducted to gain insight into the number of incidents and accidents in Dutch adult perfusion practice. An anonymous postal survey (85 questions about hardware, disposables, fluids and medication, air emboli, anticoagulation, practice, and safety measures) was sent to all Dutch perfusionists involved in adult cardiovascular perfusion during 2006 and 2007. To guarantee complete anonymity, respondents were asked to return the survey to a notary who discarded personal information. The net response rate was 72% and covered 23,500 perfusions. Individual respondents performed 240 ± 103 perfusions during the 2-year study period and had 13.8 ± 8.7 years of practical experience. The incident rate was 1 per 15.6 perfusions and the adverse event rate was 1 per 1,236 perfusions. The three most reported incidents were: (1) persistent inability to raise the activated coagulation time above 400s during perfusion (184 incidents); (2) an allergic or anaphylactic reaction to drugs, fluids, or blood products (114 incidents); and (3) clotting formation in the extracorporeal circuit (74 incidents). Furthermore, pre-bypass safety measures showed no statistically significant association with the reported incidents. In comparison with data from the recent literature, the reported number of incidents is high. Nevertheless, the adverse outcome rate is well matched to other published surveys. The relatively high response rate conveys the impression that the Dutch perfusionist is vigilant and willing to report incidents. Hence, a web-based Dutch perfusion incident registration system is recommended.

  8. Patient information leaflets for Transrectal Ultrasound guided prostate biopsy: Results of North Thames deanery survey

    PubMed Central

    2010-01-01

    Background We evaluated the quality of patient information leaflets for Trans-Rectal Ultrasound guided prostate biopsies (TRUS-Bx) in North Thames region. TRUS-Bx information leaflets were requested from 24 hospitals in the region. All hospitals were contacted by telephone, and non-responders were followed-up by postal survey. Leaflets received were evaluated for a clear description of the procedure, directions to TRUS-Bx location, a clear description of the procedure, contact for queries/concerns, information about preparation prior to procedure, information about regular medication, information on how to obtain results, instructions for follow-up arrangements, analgesia used and risk of morbidity/mortality. Additionally, the leaflets were evaluated for diagrams to clarify the procedure and the anatomy, and sources of additional information, such as reference to published articles or prostate cancer patient support groups/internet websites. Findings In summary, a total of 17 leaflets (77%) were received. Of these, the majority (94%) had a clear description of the procedure, contact for queries/concerns (82%), information about preparation prior to TRUS-Bx (71%). Directions to TRUS-Bx location (29%), and analgesia used (35%), was very poorly described, and information on obtaining results and follow-up arrangements were described in only 12 (71%) leaflets. Complications such as risks of infection, haematuria, haematospermia and rectal bleeding, were generally explained (71%-76% of leaflets), urinary retention was mentioned in only 5 (29%) leaflets and mortality in only 1 case. Descriptive diagrams of the procedure and prostate anatomy were very rarely used, and sources of additional information were limited to 1 published article and reference to 1 prostate cancer support group. Conclusions This study demonstrates that there is large variation in the information supplied in TRUS-Bx patient information leaflets in the North Thames region, with some leaflets lacking

  9. Seamless reconstruction of mitral leaflet and chordae with one piece of pericardium.

    PubMed

    Ito, Toshiaki; Maekawa, Atsuo; Aoki, Masakazu; Hoshino, Satoshi; Hayashi, Yasunari; Sawaki, Sadanari; Yanagisawa, Junji; Tokoro, Masayoshi

    2014-06-01

    Mitral valve repair is challenging when enough pliable mitral leaflets and chordae are not left intact because of extensive infective endocarditis or chronic sclerotic degeneration. For those cases, we developed a simple method to reconstruct defective leaflets and chordae en bloc with a piece of pericardium, and the mid-term results were evaluated. From January 2009 to November 2013, 25 patients with the mean age of 63 (range 20-88) years underwent this operation. The causes of mitral regurgitation were infective endocarditis in 8, sclerotic degeneration in 8, leaflet dehiscence of previous repair in 2, mitral annular calcification in 3, rheumatic in 2 and congenital in 2. After complete debridement of infected or consolidated tissue, we reconstructed defective mitral leaflets and chordae en bloc with a piece of glutaraldehyde-treated autologous pericardium. To substitute posterior leaflet and chordae, the pericardium was trimmed into a narrow pentagonal shape. The pointed end was attached directly to the corresponding papillary muscle, basal side edges to remnant leaflets on both sides, and the base to the annulus. For anterior leaflet, the pericardium was trimmed into a triangular shape if the lesion was confined in the left or right half or into a double-triangle shape if the lesion involved whole anterior leaflet. The summit of triangle was fixed to corresponding papillary muscle, and the base to remnant anterior leaflet, thus reconstructing coaptation zone and chordae seamlessly. There was no hospital death, and mitral regurgitation at discharge was none or trivial in all patients. During 1-59 months (mean 12.7) of complete follow-up, death, infection or hemolysis was not observed. In one patient, mitral regurgitation recurred 8 months postoperatively because the fixation suture of the pericardium to the papillary muscle broke. The valve was re-repaired with re-attaching the leg of the pericardium. Regurgitation was less than moderate in all other patients

  10. Saddle-shaped mitral valve annuloplasty rings improve leaflet coaptation geometry.

    PubMed

    Jensen, Morten O; Jensen, Henrik; Levine, Robert A; Yoganathan, Ajit P; Andersen, Niels Trolle; Nygaard, Hans; Hasenkam, J Michael; Nielsen, Sten L

    2011-09-01

    The mitral valve annulus naturally conforms to a saddle shape in systole. This configuration is believed to put the leaflets into a lower-energy equilibrium with the annulus and subvalvular apparatus. Conventional flat annuloplasty rings restrict posterior leaflet motion, which may result in a "monocusp" valve, affecting valvular stress distribution. It is hypothesized that saddle-shaped annuloplasty rings cause less distortion of the physiologic leaflet geometry than do flat rings. Twelve pigs were studied in an acute setting with 3-dimensional echocardiography and sonomicrometry before and after implantation of rigid flat (n = 5) and saddle-shaped (n = 7) annuloplasty rings. The rings were true sized to the annulus with equal anterior-posterior and commissure-commissure circumferential dimensions. The saddle-shaped rings had an annular height to commissural width ratio of 15%. Saddle-shaped rings maintained both leaflets operational (P < .01). Flat rings made the posterior leaflet immobile and the anterior leaflet aligned flat along the annulus in systole, effectively resulting in monoleaflet function. The average distance from the papillary muscle tips to the posterior annulus decreased by 2.4 ± 0.4 mm after flat ring implantation (P < .01). Saddle-shaped annuloplasty rings provide better leaflet coaptation geometry than do flat rings by not hoisting the papillary muscles toward the posterior annulus through the commissural chordae, allowing greater leaflet mobility. This entails a potentially beneficial impact on valvular stress distribution that could affect durability of the repaired valve. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  11. A functionally graded material model for the transmural stress distribution of the aortic valve leaflet.

    PubMed

    Rego, Bruno V; Sacks, Michael S

    2017-03-21

    Heterogeneities in structure and stress within heart valve leaflets are of significant concern to their functional physiology, as they affect how the tissue constituents remodel in response to pathological and non-pathological (e.g. exercise, pregnancy) alterations in cardiac function. Indeed, valve interstitial cells (VICs) are known to synthesize and degrade leaflet extracellular matrix (ECM) components in a manner specific to their local micromechanical environment. Quantifying local variations in ECM structure and stress is thus necessary to understand homeostatic valve maintenance as well as to develop predictive models of disease progression and post-surgical outcomes. In the aortic valve (AV), transmural variations in stress have previously been investigated by modeling the leaflet as a composite of contiguous but mechanically distinct layers. Based on previous findings about the bonded nature of these layers (Buchanan and Sacks, BMMB, 2014), we developed a more generalized structural constitutive model by treating the leaflet as a functionally graded material (FGM), whose properties vary continuously over the thickness. We informed the FGM model using high-resolution morphological measurements, which demonstrated that the composition and fiber structure change gradually over the thickness of the AV leaflet. For validation, we fit the model against an extensive database of whole-leaflet and individual-layer mechanical responses. The FGM model predicted large stress variations both between and within the leaflet layers at end-diastole, with low-collagen regions bearing significant radial stress. These novel results suggest that the continually varying structure of the AV leaflet has an important purpose with regard to valve function and tissue homeostasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Posterior ventricular anchoring neochordal repair of degenerative mitral regurgitation efficiently remodels and repositions posterior leaflet prolapse†

    PubMed Central

    Woo, Y. Joseph; MacArthur, John W.

    2013-01-01

    OBJECTIVES Mitral valve repair techniques for degenerative disease typically entail leaflet resection or neochordal construction, which may require extensive resection, leaflet detachment/reattachment, reliance on diseased native chords or precise neochordal measuring. Occasionally, impaired leaflet mobility, reduced coaptation surface and systolic anterior motion (SAM) may result. We describe a novel technique for addressing posterior leaflet prolapse/flail, which both simplifies repair and addresses these issues. METHODS Fifty-four patients (age 62 ± 11 years) with degenerative MR underwent this new repair, 36 of whom minimally-invasively. A CV5 Gore-Tex suture was placed into the posterior left ventricular myocardium underneath the prolapsing segment as an anchor. This suture was then used to imbricate a portion of the prolapsed segment into the ventricle, creating a smooth, broad, non-prolapsed coapting surface on a leaflet with preserved mobility, additional neochordal support and posteriorly positioned enough to preclude SAM. RESULTS Repair was successful in all patients. The mean MR grade was reduced from +3.8 to +0.1 with 50 of 54 patients having zero MR and 4 of the 54 having trace or mild MR. All patients had proper antero-posterior location of the coaptation line of a mean length of 10.2 mm, and preserved posterior leaflet mobility. No patients had SAM or mitral stenosis. All patients were discharged and are currently doing well. CONCLUSION This new technique facilitated efficient single-suture repair of the prolapsed posterior leaflet mitral regurgitation without the need for resection or sliding annuloplasty. It precluded the need for precise neochordal measurement and preserved the leaflet coaptation surface. PMID:23449863

  13. An evaluation of the quality of commercially produced patient information leaflets.

    PubMed

    Lewis, M A; Newton, J T

    2006-07-22

    A descriptive study was undertaken to assess the quality of a range of patient information leaflets produced by the British Dental Association. Twenty-nine leaflets were assessed with regard to presentation, readability and quality. The topic areas covered included: treatment, self-care and disease related information. Presentation was evaluated with regard to layout, font size, typeface, use of illustrations, paper type and print colour. Readability was assessed using the Flesch reading grade and the SMOG reading grade. Quality was assessed using the DISCERN tool. All leaflets scored quite well for readability, with the average SMOG Reading Grade Level being 9.10 (SD 0.80) and the average Flesch reading Grade Level being 6.18 (SD 0.83). There were, however, some areas of presentation that could be improved, specifically font size, illustration use and paper finish, which did not comply with the RNIB guidelines. Quality ratings using the DISCERN tool were low. In particular most leaflets scored poorly in setting out clear aims in the opening paragraph, in identifying sources and dates of information provided, and other sources of advice and support available. Few leaflets discussed the option of no treatment or how the treatment would affect overall quality of life. The role of shared decision making was rarely mentioned. Patient information leaflets produced commercially are of high production quality and good readability but tend not to be patient centred.

  14. Medication information leaflets for patients: the further validation of an analytic linguistic framework.

    PubMed

    Clerehan, Rosemary; Hirsh, Di; Buchbinder, Rachelle

    2009-01-01

    While clinicians may routinely use patient information leaflets about drug therapy, a poorly conceived leaflet has the potential to do harm. We previously developed a novel approach to analysing leaflets about a rheumatoid arthritis drug, using an analytic approach based on systemic functional linguistics. The aim of the present study was to verify the validity of the linguistic framework by applying it to two further arthritis drug leaflets. The findings confirmed the applicability of the framework and were used to refine it. A new stage or 'move' in the genre was identified. While the function of many of the moves appeared to be 'to instruct' the patient, the instruction was often unclear. The role relationships expressed in the text were critical to the meaning. As with our previous study, judged on their lexical density, the leaflets resembled academic text. The framework can provide specific tools to assess and produce medication information leaflets to support readers in taking medication. Future work could utilize the framework to evaluate information on other treatments and procedures or on healthcare information more widely.

  15. Unilateral optic nerve transection alters light response of suprachiasmatic nucleus and intergeniculate leaflet

    NASA Technical Reports Server (NTRS)

    Tang, I-Hsiung; Murakami, Dean M.; Fuller, Charles A.

    2002-01-01

    The suprachiasmatic nucleus (SCN), the circadian pacemaker, receives photic input directly from the retina to synchronize the pacemaker to the environment. Additionally, the intergeniculate leaflet (IGL), which innervates the SCN, is known to modulate the retinal photic input to the SCN. To further understand the role of the IGL in mediating the photic input to the SCN, this study examined the effects of unilateral optic nerve transection (UONx) on the photic response of the SCN and IGL in adult and neonatal hamsters. UONx led to an overall reduction in light-induced c-Fos expression in the SCN and IGL. The c-Fos expression was greater in the SCN ipsilateral to the remaining eye, despite a symmetrically bilateral retinohypothalamic tract projection as revealed by intraocular injection of horseradish peroxidase. In contrast, UONx led to a greater c-Fos expression in the contralateral IGL. The contralateral IGL of UONx animals also revealed more neuropeptide Y-immunoreactive neurons, while the ipsilateral SCN of these animals exhibited a denser neuropeptide Y terminal field. The neonates with UONx showed a similar pattern with a slight compensation of the photic-induced c-Fos in the SCN. This study suggests that the IGL may have an ipsilateral inhibitory effect in mediating retinal photic input to the SCN.

  16. Unilateral optic nerve transection alters light response of suprachiasmatic nucleus and intergeniculate leaflet

    NASA Technical Reports Server (NTRS)

    Tang, I-Hsiung; Murakami, Dean M.; Fuller, Charles A.

    2002-01-01

    The suprachiasmatic nucleus (SCN), the circadian pacemaker, receives photic input directly from the retina to synchronize the pacemaker to the environment. Additionally, the intergeniculate leaflet (IGL), which innervates the SCN, is known to modulate the retinal photic input to the SCN. To further understand the role of the IGL in mediating the photic input to the SCN, this study examined the effects of unilateral optic nerve transection (UONx) on the photic response of the SCN and IGL in adult and neonatal hamsters. UONx led to an overall reduction in light-induced c-Fos expression in the SCN and IGL. The c-Fos expression was greater in the SCN ipsilateral to the remaining eye, despite a symmetrically bilateral retinohypothalamic tract projection as revealed by intraocular injection of horseradish peroxidase. In contrast, UONx led to a greater c-Fos expression in the contralateral IGL. The contralateral IGL of UONx animals also revealed more neuropeptide Y-immunoreactive neurons, while the ipsilateral SCN of these animals exhibited a denser neuropeptide Y terminal field. The neonates with UONx showed a similar pattern with a slight compensation of the photic-induced c-Fos in the SCN. This study suggests that the IGL may have an ipsilateral inhibitory effect in mediating retinal photic input to the SCN.

  17. Review of laser speckle contrast techniques for visualizing tissue perfusion.

    PubMed

    Draijer, Matthijs; Hondebrink, Erwin; van Leeuwen, Ton; Steenbergen, Wiendelt

    2009-07-01

    When a diffuse object is illuminated with coherent laser light, the backscattered light will form an interference pattern on the detector. This pattern of bright and dark areas is called a speckle pattern. When there is movement in the object, the speckle pattern will change over time. Laser speckle contrast techniques use this change in speckle pattern to visualize tissue perfusion. We present and review the contribution of laser speckle contrast techniques to the field of perfusion visualization and discuss the development of the techniques.

  18. Determination of correlation between backflow volume and mitral valve leaflet young modulus from two dimensional echocardiogram images

    NASA Astrophysics Data System (ADS)

    Jong, Rudiyanto P.; Osman, Kahar; Adib, M. Azrul Hisham M.

    2012-06-01

    Mitral valve prolapse without proper monitoring might lead to a severe mitral valve failure which eventually leads to a sudden death. Additional information on the mitral valve leaflet condition against the backflow volume would be an added advantage to the medical practitioner for their decision on the patients' treatment. A study on two dimensional echocardiography images has been conducted and the correlations between the backflow volume of the mitral regurgitation and mitral valve leaflet Young modulus have been obtained. Echocardiogram images were analyzed on the aspect of backflow volume percentage and mitral valve leaflet dimensions on different rates of backflow volume. Young modulus values for the mitral valve leaflet were obtained by using the principle of elastic deflection and deformation on the mitral valve leaflet. The results show that the backflow volume increased with the decrease of the mitral valve leaflet Young modulus which also indicate the condition of the mitral valve leaflet approaching failure at high backflow volumes. Mitral valve leaflet Young modulus values obtained in this study agreed with the healthy mitral valve leaflet Young modulus from the literature. This is an initial overview of the trend on the prediction of the behaviour between the fluid and the structure of the blood and the mitral valve which is extendable to a larger system of prediction on the mitral valve leaflet condition based on the available echocardiogram images.

  19. Quantitative myocardial perfusion SPECT.

    PubMed

    Tsui, B M; Frey, E C; LaCroix, K J; Lalush, D S; McCartney, W H; King, M A; Gullberg, G T

    1998-01-01

    In recent years, there has been much interest in the clinical application of attenuation compensation to myocardial perfusion single photon emission computed tomography (SPECT) with the promise that accurate quantitative images can be obtained to improve clinical diagnoses. The different attenuation compensation methods that are available create confusion and some misconceptions. Also, attenuation-compensated images reveal other image-degrading effects including collimator-detector blurring and scatter that are not apparent in uncompensated images. This article presents basic concepts of the major factors that degrade the quality and quantitative accuracy of myocardial perfusion SPECT images, and includes a discussion of the various image reconstruction and compensation methods and misconceptions and pitfalls in implementation. The differences between the various compensation methods and their performance are demonstrated. Particular emphasis is directed to an approach that promises to provide quantitative myocardial perfusion SPECT images by accurately compensating for the 3-dimensional (3-D) attenuation, collimator-detector response, and scatter effects. With advances in the computer hardware and optimized implementation techniques, quantitatively accurate and high-quality myocardial perfusion SPECT images can be obtained in clinically acceptable processing time. Examples from simulation, phantom, and patient studies are used to demonstrate the various aspects of the investigation. We conclude that quantitative myocardial perfusion SPECT, which holds great promise to improve clinical diagnosis, is an achievable goal in the near future.

  20. Ex vivo lung perfusion.

    PubMed

    Reeb, Jeremie; Cypel, Marcelo

    2016-03-01

    Lung transplantation is an established life-saving therapy for patients with end-stage lung disease. Unfortunately, greater success in lung transplantation is hindered by a shortage of lung donors and the relatively poor early-, mid-, and long-term outcomes associated with severe primary graft dysfunction. Ex vivo lung perfusion has emerged as a modern preservation technique that allows for a more accurate lung assessment and improvement in lung quality. This review outlines the: (i) rationale behind the method; (ii) techniques and protocols; (iii) Toronto ex vivo lung perfusion method; (iv) devices available; and (v) clinical experience worldwide. We also highlight the potential of ex vivo lung perfusion in leading a new era of lung preservation.

  1. Distribution of the microelastic properties within the human anterior mitral leaflet.

    PubMed

    Jensen, Anne Skakkebaek; Baandrup, Ulrik; Hasenkam, J Michael; Kundu, Tribikram; Jørgensen, Claus Schiøtt

    2006-12-01

    Knowledge of the biomechanical properties of the mitral valve leaflets and their relation to histologic structure is of importance for understanding the leaflet movement characteristics under normal and pathologic conditions, but such knowledge is not yet available. The aim of this study was to determine biomechanical properties of the human anterior mitral leaflet on a microscopic scale. We used scanning acoustic microscopy (SAM) to examine the human anterior mitral leaflet. Sections of fixed human anterior mitral leaflet tissue were obtained from postmortem human anterior mitral leaflets (n = 5). We measured the speed of sound (nu(L)) in each histologic layer in three regions-of-interest (ROIs): these were at the annular edge, at the valve midpoint and close to the free edge. nu(L) varied in the three histologic layers (p < 0.01). It was higher in the fibrous layer (1.76 km/s) compared with the atrial layer (1.75 km/s) and ventricular layer (1.73 km/s). Also, nu(L) differed between positions along the length of the annulus-free edge line (p < 0.01), showing a decline from the annular edge (1.76 km/s) to the free edge (1.73 km/s), both as a whole and also within the atrial and the fibrous layer. These results demonstrate that the fibrous layer is stiffer than the atrial and ventricular layer and that the leaflet as a whole and within the atrial and the fibrous layer is stiffer at the annulus part in comparison with those near the free edge. (E-mail: ).

  2. [Portable peristaltic perfusion pumps].

    PubMed

    Magallón Pedrera, I; Soto Torres, I

    1999-11-01

    Portable peristaltic perfusion pumps allow one to administer pharmaceuticals in hospitals as well as in primary health care centers and furthermore these pumps present multiple advantages for patients and their families since they make it possible to carry out treatment in a patient's home while at the same time lowering the costs involved. The authors analyze the most out standing aspects of portable peristaltic perfusion pumps along with their characteristics, installation, programming, and how to turn them on; in addition, the authors list the maintenance care which these pumps require.

  3. Intentional Laceration of the Anterior Mitral Valve Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement

    PubMed Central

    Khan, Jaffar M.; Rogers, Toby; Schenke, William H.; Mazal, Jonathan R.; Faranesh, Anthony Z.; Greenbaum, Adam B.; Babaliaros, Vasilis C.; Chen, Marcus Y.; Lederman, Robert J.

    2017-01-01

    OBJECTIVES The authors propose a novel transcatheter transection of the anterior mitral leaflet to prevent iatrogenic left ventricular outflow tract (LVOT) obstruction during transcatheter mitral valve replacement (TMVR). BACKGROUND LVOT obstruction is a life-threatening complication of TMVR caused by septal displacement of the anterior mitral leaflet. METHODS In vivo procedures in swine were guided by biplane x-ray fluoroscopy and intracardiac echocardiography. Retrograde transaortic 6-F guiding catheters straddled the anterior mitral leaflet. A stiff 0.014-inch guidewire with polymer jacket insulation was electrified and advanced from the LVOT, through the A2 leaflet base, into the left atrium. The wire was snared and externalized, forming a loop that was energized and withdrawn to lacerate the anterior mitral leaflet. RESULTS The anterior mitral leaflet was successfully lacerated in 7 live and 1 post-mortem swine under heparinization. Lacerations extended to 89 ± 19% of leaflet length and were located within 0.5 ± 0.4 mm of leaflet centerline. The chordae were preserved and retracted the leaflet halves away from the LVOT. LVOT narrowing after benchtop TMVR was significantly reduced with intentional laceration of the anterior mitral leaflet to prevent LVOT obstruction than without (65 ± 10% vs. 31 ± 18% of pre-implantation diameter, p < 0.01). The technique caused mean blood pressure to fall (from 54 ± 6 mm Hg to 30 ± 4 mm Hg, p < 0.01), but blood pressure remained steady until planned euthanasia. No collateral tissue injury was identified on necropsy. CONCLUSIONS Using simple catheter techniques, the anterior mitral valve leaflet was transected. Cautiously applied in patients, this strategy can prevent anterior mitral leaflet displacement and LVOT obstruction caused by TMVR. PMID:27609260

  4. Charged anaesthetics alter LM-fibroblast plasma-membrane enzymes by selective fluidization of inner or outer membrane leaflets.

    PubMed

    Sweet, W D; Schroeder, F

    1986-10-15

    The functional consequences of the differences in lipid composition and structure between the two leaflets of the plasma membrane were investigated. Fluorescence of 1,6-diphenylhexa-1,3,5-triene(DPH), quenching, and differential polarized phase fluorimetry demonstrated selective fluidization by local anaesthetics of individual leaflets in isolated LM-cell plasma membranes. As measured by decreased limiting anisotropy of DPH fluorescence, cationic (prilocaine) and anionic (phenobarbital and pentobarbital) amphipaths preferentially fluidized the cytofacial and exofacial leaflets respectively. Unlike prilocaine, procaine, also a cation, fluidized both leaflets of these membranes equally. Pentobarbital stimulated 5'-nucleotidase between 0.1 and 5 mM and inhibited at higher concentrations, whereas phenobarbital only inhibited, at higher concentrations. Cationic drugs were ineffective. Two maxima of (Na+ + K+)-ATPase activation were obtained with both anionic drugs. Only one activation maximum was obtained with both cationic drugs. The maximum in activity below 1 mM for all four drugs clustered about a single limiting anisotropy value in the cytofacial leaflet, whereas there was no correlation between activity and limiting anisotropy in the exofacial leaflets. Therefore, although phenobarbital and pentobarbital below 1 mM fluidized the exofacial leaflet more than the cytofacial leaflet, the smaller fluidization in the cytofacial leaflet was functionally significant for (Na+ + K+)-ATPase. Mg2+-ATPase was stimulated at 1 mM-phenobarbital, unaffected by pentobarbital and slightly stimulated by both cationic drugs at concentrations fluidizing both leaflets. Thus the activity of (Na+ + K+)-ATPase was highly sensitive to selective fluidization of the leaflet containing its active site, whereas the other enzymes examined were little affected by fluidization of either leaflet.

  5. Role of myocardial perfusion single photon emission computed tomography in pediatric cardiology practice

    PubMed Central

    Sundaram, P Shanmuga; Padma, S

    2009-01-01

    Diagnostic and prognostic power of myocardial perfusion imaging in patients with coronary artery disease has been demonstrated with planar imaging which was further improvised with addition of gated SPECT and newer Technetium labeled myocardial perfusion tracers like SestaMIBI, Tetrofosmin. Myocardial perfusion abnormalities at rest and after stress are considered to be the best predictors of cardiac event–free survival in adults with ischemic heart disease. This article highlights various myocardial perfusion imaging (MPI) radiopharmaceuticals, exercise procedures, pharmacological stress protocols, indications for MPI and myocardial perfusion patterns in children with some of the common congenital and acquired heart diseases. PMID:20808625

  6. The influence of saddle-shaped annuloplasty on leaflet curvature in patients with ischaemic mitral regurgitation.

    PubMed

    Vergnat, Mathieu; Levack, Melissa M; Jassar, Arminder S; Jackson, Benjamin M; Acker, Michael A; Woo, Y Joseph; Gorman, Robert C; Gorman, Joseph H

    2012-09-01

    Reports indicate that repair procedures for ischaemic mitral regurgitation (IMR) are less durable than previously thought. Repair failure has been shown to be stress related. Leaflet curvature is the major determinant of valve stress. Theoretical and animal experiments have shown that saddle-shaped annuloplasty optimizes leaflet curvature when compared with standard flat ring annuloplasty. Despite this, the influence of the ring shape on leaflet curvature has not been described in patients with IMR. This study uses real-time three-dimensional echocardiography (rt-3DE) to assess the influence of the ring shape on leaflet curvature. Rt-3DE was performed in 21 patients with IMR after placement of either a flat (n = 10, CE-Physio, Edwards) or saddle-shaped (n = 11, Profile 3D, Medtronic) annuloplasty ring. A combination of commercially available and customized software was used to measure multiple leaflet curvature parameters across all regions of the mitral valve. Independently of the shape of the annuloplasty ring, all patients were subject to the same degree of annular undersizing. Patients who received saddle-shaped annuloplasty rings had greater leaflet curvature in all six mitral valve leaflet regions (A1 = 0.36 ± 0.10, A2 = 0.53 ± 0.13, A3 = 0.47 ± 0.13, P1 = 0.35 ± 0.23, P2 = 0.53 ± 0.34, P3 = 0.42 ± 0.20 cm(-2)) compared with patients who received flat annuloplasty rings (A1 = 0.16 ± 0.11, A2 = 0.18 ± 0.09, A3 = 0.16 ± 0.11, P1 = 0.20 ± 0.17, P2 = 0.21 ± 0.11, P3 = 0.18 ± 0.13 cm(-2)). These differences were statistically significant in all regions except the P1 region. Saddle-shaped annuloplasty rings increase leaflet curvature compared with flat rings in patients with IMR. As a result, saddle-shaped annuloplasty may decrease leaflet stress and potentially increases the durability of the repair in patients with IMR.

  7. Mid-term results of leaflet augmentation in severe tricuspid functional tethering.

    PubMed

    Pettinari, Matteo; Bertrand, Philippe; Van Kerrebroeck, Christiaan; Vandervoort, Pieter; Gutermann, Herbert; Dion, Robert

    2016-09-01

    Functional tricuspid regurgitation (FTR) is usually managed surgically using various types of annuloplasty. FTR has been reported to recur in up to 45% of patients, with severe leaflet tethering being an important risk factor for recurrence. The aim of this study is to report the clinical and echocardiographic mid-term results after leaflet augmentation in patients with FTR due to severe leaflet tethering. From May 2008 to July 2014, 22 patients were found to have a severe FTR with a tethering height of at least 8 mm; all of them underwent leaflet augmentation: the anterior and part of the posterior leaflet were detached from the anterior annulus; a patch of fresh autologous pericardium was used to generously fill the gap between the anterior annulus and the detached leaflet. A 5/0 Pronova suture locked at every step was used to avoid any purse string effect. In 2 patients, the septal leaflet also needed to be augmented using a comparable technique. In all but one (annular calcification) patient, a semi-rigid ring annuloplasty was added. The mean age was 67.1 ± 13.7 years; it was a redo procedure in 12 cases (54.5%), 11 patients (50%) had right ventricle failure and 3 (23.1%) had renal failure. The median follow-up was 2.1 ± 1.9 years. Thirty-day and 4-year survival averaged at 81.1 ± 8.5 and 71.6 ± 9.8%, respectively. At 4 years, 84 ± 10.6% of the survivors were in NYHA class I or II and only 2 patients had a TR of ≥2 with a global freedom from TR ≥2 of 85.7 ± 13.2%. There was no reintervention. Tricuspid leaflet augmentation combined with annuloplasty is feasible and leads to excellent clinical and echocardiographical mid-term results even in the presence of severe leaflet tethering and right ventricular failure. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  8. Aortic valve leaflet replacement with bovine pericardium to preserve native dynamic capabilities of the aortic annulus.

    PubMed

    Kim, Kyung Hwa; Choi, Jong Bum; Kim, Min Ho; Kim, Won Ho; Lee, Mi Kyung; Lee, Sam Youn

    2014-02-01

    Valve replacement is typically the most appropriate option for treating aortic valve stenotic insufficiency. However, neither mechanical nor bioprosthetic replacement components preserve the circumferential expansion and contraction of a native aortic annulus during the cardiac cycle, because the prosthetic ring is affixed to the annulus. A 64-year-old man presented with a bicuspid and stenotic aortic valve, and the native annulus was too small to accommodate a porcine replacement valve. We fashioned new aortic leaflets from bovine pericardium with use of a template, and we affixed the sinotubular junction with use of inner and outer stabilization rings. Postoperative echocardiograms revealed coaptation of the 3 new leaflets with no regurgitation. At the patient's 5.5-year follow-up examination, echocardiograms showed flexible leaflet movement with a coaptation height of 7 mm, and expansion and contraction of the aortic annulus similar to that of a normal native annulus. The transvalvular pressure gradient was insignificant. If long-term durability of the new leaflets is confirmed, this method of leaflet replacement and fixation of the sinotubular junction might serve as an acceptable alternative to valve replacement in the treatment of aortic valve stenosis. We describe the patient's case and present our methods and observations.

  9. Aortic Valve Leaflet Replacement with Bovine Pericardium to Preserve Native Dynamic Capabilities of the Aortic Annulus

    PubMed Central

    Kim, Kyung Hwa; Kim, Min Ho; Kim, Won Ho; Lee, Mi Kyung; Lee, Sam Youn

    2014-01-01

    Valve replacement is typically the most appropriate option for treating aortic valve stenotic insufficiency. However, neither mechanical nor bioprosthetic replacement components preserve the circumferential expansion and contraction of a native aortic annulus during the cardiac cycle, because the prosthetic ring is affixed to the annulus. A 64-year-old man presented with a bicuspid and stenotic aortic valve, and the native annulus was too small to accommodate a porcine replacement valve. We fashioned new aortic leaflets from bovine pericardium with use of a template, and we affixed the sinotubular junction with use of inner and outer stabilization rings. Postoperative echocardiograms revealed coaptation of the 3 new leaflets with no regurgitation. At the patient's 5.5-year follow-up examination, echocardiograms showed flexible leaflet movement with a coaptation height of 7 mm, and expansion and contraction of the aortic annulus similar to that of a normal native annulus. The transvalvular pressure gradient was insignificant. If long-term durability of the new leaflets is confirmed, this method of leaflet replacement and fixation of the sinotubular junction might serve as an acceptable alternative to valve replacement in the treatment of aortic valve stenosis. We describe the patient's case and present our methods and observations. PMID:24512414

  10. Oenocarpus bacaba and Oenocarpus bataua Leaflets and Roots: A New Source of Antioxidant Compounds

    PubMed Central

    Leba, Louis-Jérôme; Brunschwig, Christel; Saout, Mona; Martial, Karine; Bereau, Didier; Robinson, Jean-Charles

    2016-01-01

    Native palm trees fruit from the Amazonian rainforest, Oenocarpus bacaba and Oenocarpus bataua, are very often used in the diet of local communities, but the biological activities of their roots and leaflets remain poorly known. Total phenolic content (TPC) and antioxidant activity of root and leaflet extracts from Oenocarpus bacaba and Oenocarpus bataua were assessed by using different chemical assays, the oxygèn radical absorbance capacity (ORAC), the 2,2-diphenyl-l-picrylhydrazyl (DPPH) free radical-scavenging capacity and the ferric-reducing ability of plasma (FRAP). Cellular antioxidant activity and cytotoxicity were also measured in Normal Human Dermal Fibroblasts. The polyphenolic composition of Oenocarpus extracts was investigated by LC-MSn. Oenocarpus leaflet extracts were more antioxidant than root extracts, being at least as potent as Euterpe oleracea berries known as superfruit. Oenocarpus root extracts were characterized by hydroxycinnamic acids (caffeoylquinic and caffeoylshikimic acids), while leaflet extracts contained mainly caffeoylquinic acids and C-glycosyl flavones. These results suggest that leaflets of both Oenocarpus species could be valorized as a new non-cytotoxic source of antioxidants from Amazonia, containing hydroxycinnamic acids and flavonoids, in the pharmaceutical, cosmetic or agri-food industry. PMID:27355943

  11. Modeling active muscle contraction in mitral valve leaflets during systole: a first approach.

    PubMed

    Skallerud, B; Prot, V; Nordrum, I S

    2011-02-01

    The present study addresses the effect of muscle activation contributions to mitral valve leaflet response during systole. State-of-art passive hyperelastic material modeling is employed in combination with a simple active stress part. Fiber families are assumed in the leaflets: one defined by the collagen and one defined by muscle activation. The active part is either assumed to be orthogonal to the collagen fibers or both orthogonal to and parallel with the collagen fibers (i.e. an orthotropic muscle fiber model). Based on data published in the literature and information herein on morphology, the size of the leaflet parts that contain muscle fibers is estimated. These parts have both active and passive materials, the remaining parts consist of passive material only. Several solid finite element analyses with different maximum activation levels are run. The simulation results are compared to corresponding echocardiography at peak systole for a porcine model. The physiologically correct flat shape of the closed valve is approached as the activation levels increase. The non-physiological bulging of the leaflet into the left atrium when using passive material models is reduced significantly. These results contribute to improved understanding of the physiology of the native mitral valve, and add evidence to the hypothesis that the mitral valve leaflets not are just passive elements moving as a result of hemodynamic pressure gradients in the left part of the heart.

  12. Distribution of perfusion.

    PubMed

    Glenny, Robb; Robertson, H Thomas

    2011-01-01

    Local driving pressures and resistances within the pulmonary vascular tree determine the distribution of perfusion in the lung. Unlike other organs, these local determinants are significantly influenced by regional hydrostatic and alveolar pressures. Those effects on blood flow distribution are further magnified by the large vertical height of the human lung and the relatively low intravascular pressures in the pulmonary circulation. While the distribution of perfusion is largely due to passive determinants such as vascular geometry and hydrostatic pressures, active mechanisms such as vasoconstriction induced by local hypoxia can also redistribute blood flow. This chapter reviews the determinants of regional lung perfusion with a focus on vascular tree geometry, vertical gradients induced by gravity, the interactions between vascular and surrounding alveolar pressures, and hypoxic pulmonary vasoconstriction. While each of these determinants of perfusion distribution can be examined in isolation, the distribution of blood flow is dynamically determined and each component interacts with the others so that a change in one region of the lung influences the distribution of blood flow in other lung regions. © 2011 American Physiological Society.

  13. Contactless mapping of rhythmical phenomena in tissue perfusion using PPGI

    NASA Astrophysics Data System (ADS)

    Huelsbusch, Markus; Blazek, Vladimir

    2002-04-01

    This paper presents the experimental setup and preliminary results of a near infrared CCD camera based Photoplethysmography Imaging (PPGI) system, which has been shown to be suitable for contactless and spatially resolved assessment of rhythmical blood volume changes in the skin. To visualize the complex rhythmical patterns in the dermal perfusion the Wavelet Transform is utilized. It is able to jointly assess time and frequency behavior of signals and thus allows to analyze instationary oscillations and variabilities in the different human rhythmics. The presented system is expected to provide new insights into the functional sequences of physiological tissue perfusion as well as of the perfusion status in ulcer formation and wound healing.

  14. Finite element modeling of mitral leaflet tissue using a layered shell approximation

    PubMed Central

    Ratcliffe, Mark B.; Guccione, Julius M.

    2012-01-01

    The current study presents a finite element model of mitral leaflet tissue, which incorporates the anisotropic material response and approximates the layered structure. First, continuum mechanics and the theory of layered composites are used to develop an analytical representation of membrane stress in the leaflet material. This is done with an existing anisotropic constitutive law from literature. Then, the concept is implemented in a finite element (FE) model by overlapping and merging two layers of transversely isotropic membrane elements in LS-DYNA, which homogenizes the response. The FE model is then used to simulate various biaxial extension tests and out-of-plane pressure loading. Both the analytical and FE model show good agreement with experimental biaxial extension data, and show good mutual agreement. This confirms that the layered composite approximation presented in the current study is able to capture the exponential stiffening seen in both the circumferential and radial directions of mitral leaflets. PMID:22971896

  15. Leaflet motion abnormality after TAVI: genuine threat or much ado about nothing?

    PubMed

    Chakravarty, Tarun; Abramowitz, Yigal; Jilaihawi, Hasan; Makkar, Raj R

    2016-09-18

    Symptomatic transcatheter heart valve (THV) thrombosis is noted in up to 1% of patients after transcatheter aortic valve replacement. Recently, hypoattenuated leaflet thickening and reduced leaflet motion of bioprosthetic aortic valves associated with normal transvalvular gradients (and possibly related to subclinical leaflet thrombosis) have been reported. While trans-thoracic echocardiography is a useful initial screening imaging modality for the detection of symptomatic THV thrombosis associated with elevated transvalvular gradients, it has limited utility in the detection of subclinical THV thrombosis. In the present article, we describe the incidence, clinical presentation and strategies for the prevention and treatment of THV thrombosis, as well as the role of imaging modalities in the diagnosis and management of this phenomenon.

  16. Autoradiographic characterization of beta-adrenoceptors in rat heart valve leaflets

    SciTech Connect

    Pinto, J.E.; Nazarali, A.J.; Torda, T.; Saavedra, J.M.

    1989-03-01

    beta-Adrenoceptors were localized and characterized in valve leaflets of the rat heart. Sixteen micrometer-thick tissue sections containing the mitral and aortic valves were incubated with (-)3-(/sup 125/I)iodocyanopindolol followed by autoradiography with computerized microdensitometry and comparison with /sup 125/I-labeled standards. beta-Adrenoceptors were present in all the valves studied. The selective beta 1-adrenoceptor antagonist CGP 20712 A (100 nM) displaced not more than 20% of the total binding sites, suggesting that most of the beta-adrenoceptors in the valve leaflets are of the beta 2-subtype. Forskolin-binding sites were detected in the mitral valve leaflet by incubation of adjacent tissue sections with (12-/sup 3/H)forskolin. Our results indicate that catecholamines could regulate the function of the heart valves through stimulation of beta 2-adrenoceptors.

  17. Educating adolescents about healthy sleep: experimental study of effectiveness of educational leaflet.

    PubMed

    Bakotić, Marija; Radosević-Vidacek, Biserka; Kosćec, Adrijana

    2009-04-01

    To evaluate how exposure to educational leaflet about healthy sleep affects knowledge about sleep in adolescents. The study included students aged 15-18 years from 12 high schools (1209 participants; 85% of eligible study population). Multistage sampling was used and the selected schools were randomly assigned into two intervention groups and two control groups, according to the Solomon experimental design. Intervention groups received educational leaflets and control groups did not. In one of the intervention groups and one of the control groups, pre-testing of knowledge about sleep was performed. Students answered the Sleep Knowledge Test, which was constructed in accordance with the information on the leaflet. Data were analyzed by four-way ANOVA and additional analyses of simple main effects were performed. Positive effect of educational leaflet was found in students aged 15 (F = 28.46; P < 0.001), 16 (F = 5.74; P = 0.017), and 17 (F = 17.17; P < 0.001), but there was no effect in students aged 18 (P = 0.467). In male students, positive effect of the leaflet was found only in the group that had not been pre-tested (F = 6.29; P = 0.012), while in female students, it was found in both pre-tested (F = 26.24; P < 0.001) and not pre-tested group (F = 17.36; P < 0.001), with greater effect in pre-tested group (F = 5.70; P = 0.017). Female students generally showed better knowledge about sleep than male students (F = 95.95; P < 0.001). Educational leaflets can be an effective first step in educating younger high school students about healthy sleep, with the method being more effective in female adolescents.

  18. A Coarse Grained Model for a Lipid Membrane with Physiological Composition and Leaflet Asymmetry

    PubMed Central

    Sharma, Satyan; Kim, Brian N.; Stansfeld, Phillip J.; Sansom, Mark S. P.; Lindau, Manfred

    2015-01-01

    The resemblance of lipid membrane models to physiological membranes determines how well molecular dynamics (MD) simulations imitate the dynamic behavior of cell membranes and membrane proteins. Physiological lipid membranes are composed of multiple types of phospholipids, and the leaflet compositions are generally asymmetric. Here we describe an approach for self-assembly of a Coarse-Grained (CG) membrane model with physiological composition and leaflet asymmetry using the MARTINI force field. An initial set-up of two boxes with different types of lipids according to the leaflet asymmetry of mammalian cell membranes stacked with 0.5 nm overlap, reliably resulted in the self-assembly of bilayer membranes with leaflet asymmetry resembling that of physiological mammalian cell membranes. Self-assembly in the presence of a fragment of the plasma membrane protein syntaxin 1A led to spontaneous specific positioning of phosphatidylionositol(4,5)bisphosphate at a positively charged stretch of syntaxin consistent with experimental data. An analogous approach choosing an initial set-up with two concentric shells filled with different lipid types results in successful assembly of a spherical vesicle with asymmetric leaflet composition. Self-assembly of the vesicle in the presence of the synaptic vesicle protein synaptobrevin 2 revealed the correct position of the synaptobrevin transmembrane domain. This is the first CG MD method to form a membrane with physiological lipid composition as well as leaflet asymmetry by self-assembly and will enable unbiased studies of the incorporation and dynamics of membrane proteins in more realistic CG membrane models. PMID:26659855

  19. Fresh autologous pericardium for leaflet perforation repair in mitral valve infective endocarditis.

    PubMed

    Evans, Charles F; DeFilippi, Christopher R; Shang, Eric; Griffith, Bartley P; Gammie, James S

    2013-07-01

    There is clear evidence that mitral valve (MV) repair is superior to replacement for MV infective endocarditis (IE). Leaflet perforation is a common pathologic finding in MV IE, and leaflet patch repair with glutaraldehyde-treated autologous or bovine pericardium is the currently accepted method of MV repair. In the present study, fresh autologous pericardium (FAP) was used universally to treat leaflet perforation in MV IE, and the mid-term clinical and echocardiographic outcomes were determined. Between 2002 and 2009, a total of 20 patients with leaflet perforations from MV IE underwent patch repair with FAP. Follow up echocardiography was performed in a core laboratory. There was one operative death (5%) secondary to sepsis, and three late deaths (15%). Late echocardiograms were available for review from 16 of the 19 patients (84%) who survived surgery. The mean time to follow up echocardiography was 793 +/- 663 days. The mitral regurgitation (MR) grade was mild or less in 14/16 patients (88%), moderate in one patient (6%), and severe in one patient (6%). The mean gradient was 4.8 +/- 2.7 mmHg, and the ejection fraction was preserved in all patients (63 +/- 4%). No expansion, retraction or calcification of the patches was observed. Freedom from reoperation, reinfection and thromboembolism was 100%. Fresh autologous pericardium for MV leaflet patch repair in IE is associated with good mid-term valve function. Given the association between late calcification and the glutaraldehyde treatment of bioprosthetic valves and this favorable experience, it is believed that FAP is an acceptable alternative for leaflet repair in MV IE.

  20. The flexural rigidity of the aortic valve leaflet in the commissural region.

    PubMed

    Mirnajafi, Ali; Raymer, Jeremy M; McClure, Leigh R; Sacks, Michael S

    2006-01-01

    Flexure is a major deformation mode of the aortic valve (AV) leaflet, particularly in the commissural region where the upper portion of the leaflet joins the aortic root. However, there are no existing data known on the mechanical properties of leaflet in the commissural region. To address this issue, we quantified the effective stiffness of the commissural region using a cantilever beam method. Ten specimens were prepared, with each specimen flexed in the direction of natural leaflet motion (forward) and against the natural motion (reverse). At a flexure angle (phi) of 30 degrees , the effective forward direction modulus E was 42.63+/-4.44 kPa and the reverse direction E was 75.01+/-14.53 kPa (p=0.049). Further, E-phi response was linear (r(2) approximately 0.9) in both flexural directions. Values for dE/dphi were -2.24+/-0.6 kPa/ degrees and -1.90+/-0.3 kPa/ degrees in the forward and reverse directions, respectively (not statistically different, p=0.424), indicating a consistent decrease in stiffness with increased flexure. In comparison, we have reported that the effective tissue stiffness of AV leaflet belly region was 150-200 kPa [Merryman, W.D., Huang, H.Y.S., Schoen, F.J., Sacks, M.S. (2006). The effects of cellular contraction on AV leaflet flexural stiffness. Journal of Biomechanics 39 (1), 88-96], which was also independent of direction and amount of flexure. Histological studies of the commissure region indicated that tissue buckling was a probable mechanism for decrease in E with increasing flexure. The observed change in E with flexural angle in the commissural region is a subtle aspect of valve function. From a valve design perspective, these findings can be used as design criteria in fabricating prosthetic devices AV resulting in better functional performance.

  1. Determining the Combined Effect of the Lymphatic Valve Leaflets and Sinus on Resistance to Forward Flow

    PubMed Central

    Wilson, John T.; van Loon, Raoul; Wang, Wei; Zawieja, David C.; Moore, James E.

    2015-01-01

    The lymphatic system is vital to a proper maintenance of fluid and solute homeostasis. Collecting lymphatics are composed of actively contracting tubular vessels segmented by bulbous sinus regions that encapsulate bi-leaflet check valves. Valve resistance to forward flow strongly influences pumping performance. However, because of the sub-millimeter size of the vessels with flow rates typically < 1 ml/hour and pressures of a few cmH2O, resistance is difficult to measure experimentally. Using a newly defined idealized geometry, we employed an uncoupled approach where the solid leaflet deflections of the open valve were computed and lymph flow calculations were subsequently performed. We sought to understand: 1) the effect of sinus and leaflet size on the resulting deflections experienced by the valve leaflets and 2) the effects on valve resistance to forward flow of the fully open valve. For geometries with sinus-to-root diameter ratios > 1.39, the average resistance to forward flow was 0.95 × 106 [g/(cm4 s)]. Compared to the viscous pressure drop that would occur in a straight tube the same diameter as the upstream lymphangion, valve leaflets alone increase the pressure drop up to 35%. However, the presence of the sinus reduces viscous losses, with the net effect that when combined with leaflets the overall resistance is less than that of the equivalent continuing straight tube. Accurately quantifying resistance to forward flow will add to the knowledge used to develop therapeutics for treating lymphatic disorders and may eventually lead to understanding some forms of primary lymphedema. PMID:26315921

  2. Two distinct subpopulations of neurons in the thalamic intergeniculate leaflet identified by subthreshold currents.

    PubMed

    Chrobok, Lukasz; Palus, Katarzyna; Lewandowski, Marian Henryk

    2016-08-04

    The intergeniculate leaflet (IGL) is a flat retinorecipient thalamic structure implicated in orchestrating circadian rhythm, historically considered to be a subdivision of the neighboring ventrolateral geniculate nucleus (VLG). IGL consists of two main neuronal subpopulations: enkephalinergic and neuropeptide Y (NPY)-synthesizing cells. These cell types have different functions, connectivity and firing pattern in vivo, which suggest that they have different membrane currents to support their functional differences. We therefore performed patch-clamp experiments combined with immunohistochemical staining to clarify possible differences in the subthreshold currents of IGL neurons. Our results suggest that IGL neurons can be divided into two subpopulations based on two ionic currents. A T-type calcium current (IT) was identified in neurons that do not synthesise NPY, whereas all NPY-positive neurons were found to express a marked A-type potassium current (IA). Due to the fact that the clear electrophysiological discriminants between IGL and VLG are lacking, we decided to compare the amplitudes of the identified currents between those two structures. Our data suggest that VLG neurons can be characterized by a high amplitude IT and a low IA. Finally, we compared both currents with WAG/Rij rats, a well-established model of absence epilepsy, with co-occurring retinal pathologies, sleep-onset disturbances, and seizures exhibiting circadian rhythmicity. Data presented in this study uncovered pathologies in the IT exhibiting neurons of the IGL and VLG. In conclusion, the data presented here suggest that different subthreshold current expression supports the functional differences of thalamic nuclei. Those differences are promising for possible pharmacological manipulations of specified cell types in pathophysiologies including absence epilepsy. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  3. Disinhibition of the intergeniculate leaflet network in the WAG/Rij rat model of absence epilepsy.

    PubMed

    Chrobok, Lukasz; Palus, Katarzyna; Jeczmien-Lazur, Jagoda Stanislawa; Chrzanowska, Anna; Kepczynski, Mariusz; Lewandowski, Marian Henryk

    2017-03-01

    The intergeniculate leaflet (IGL) of the thalamus is a retinorecipient structure implicated in orchestrating circadian rhythmicity. The IGL network is highly GABAergic and consists mainly of neuropeptide Y-synthesising and enkephalinergic neurons. A high density of GFAP-immunoreactive astrocytes has been observed in the IGL, with a probable function in guarding neuronal inhibition. Interestingly, putatively enkephalinergic IGL neurons generate action potentials with an infra-slow oscillatory (ISO) pattern in vivo in urethane anesthetised Wistar rats, under light-on conditions only. Absence epilepsy (AE) is a disease characterised by spike-wave discharges present in the encephalogram, directly caused by hypersynchronous thalamo-cortical oscillations. Many pathologies connected with the arousal system, such as abnormalities in sleep architecture and an insufficient brain sleep-promoting system accompany the epileptic phenotype. We hypothesise that disturbances in the function of biological clock structures, controlling this rhythmic physiological process, may be responsible for the observed pathomechanism. To test this hypothesis, we performed an in vitro patch-clamp study on WAG/Rij rats, a well-validated genetic model of AE, in order to assess dampened GABAergic synaptic transmission in the IGL expressed as a lower IPSC amplitude and reduced sIPSC frequency. Moreover, our in vivo extracellular recordings showed higher firing rate of ISO IGL neurons with an abnormal reaction to a change in constant illumination (maintenance of rhythmic neuronal activity in darkness) in the AE model. Additional immunohistochemical experiments indicated astrogliosis in the area of the IGL, which may partially underlie the observed changes in inhibition. Altogether, the data presented here show for the first time the disinhibition of IGL neurons in a model of AE, thereby proposing the possible involvement of circadian-related brain structures in the epileptic phenotype. Copyright

  4. Cross-correlation analysis of inner-leaflet-anchored green fluorescent protein co-redistributed with IgE receptors and outer leaflet lipid raft components.

    PubMed Central

    Pyenta, P S; Holowka, D; Baird, B

    2001-01-01

    To investigate the structural basis for membrane interactions that occur between Lyn tyrosine kinase and IgE-Fc(epsilon)RI or other components of lipid rafts, we prepared a green fluorescent protein analog of Lyn (PM-EGFP) and used cross-correlation analysis to quantify co-redistributions of aggregates that occur after IgE-Fc(epsilon)RI is cross-linked on the cell surface. PM-EGFP, which contains minimally the palmitoylation and myristoylation sites on Lyn, was compared with another inner leaflet probe, EGFP-GG, which contains a prenylation site and a polybasic sequence similar to K-ras. Confocal fluorescence microscopy was used to examine co-redistributions of these inner leaflet components with IgE-Fc(epsilon)RI and outer leaflet raft components, ganglioside GD1b and glycosylphosphotidylinositol-linked Thy-1, under conditions where the latter were cross-linked externally to form large patches at the cell surface. The cross-correlation analysis was developed and characterized with simulations representing cell surface distributions, and parameters from the cross-correlation curves, rho(o) (peak height) and A (peak area), were shown to be reliable measures of the extent of co-redistributed aggregates and their size. Cross-correlation analysis was then applied to quantify co-redistributions of the fluorescently labeled inner and outer leaflet components on RBL-2H3 cells. As visually observed and parameterized in this manner, PM-EGFP was found to co-redistribute with lipid rafts significantly more than EGFP-GG or an endogenous prenylated protein, Cdc42. These quantitative results are consistent with previous analyses of Lyn co-redistributions and support the hypothesis that the functionally important interaction of Lyn with cross-linked IgE- Fc(epsilon)RI is due to their mutual co-association with lipid rafts. PMID:11325715

  5. Right atrial aneurysm with downward displacement of the anterior leaflet that resembled Ebstein's anomaly.

    PubMed

    Yamauchi, Sanae; Suzuki, Yasuyuki; Daitoku, Kazuyuki; Kimura, Masaomi; Okumura, Ken; Fukuda, Ikuo

    2016-06-08

    A 13-year-old boy presented with right atrial aneurysm and downward displacement of the anterior leaflet in the tricuspid valve into the right ventricle, without tricuspid valve regurgitation. Paroxysmal atrial flutter was caused by an abnormal electrical re-entry circuit, which could not be treated using catheter radiofrequency ablation. Therefore, the patient underwent surgical ablation and resection of the enlarged right atrial wall. The anterior leaflet of the tricuspid valve was plastered and displaced downward into the right ventricle, which resembled Ebstein's anomaly. Pathological evaluation revealed a thin wall that contained fibrous tissue with lipomatous degeneration and few muscular elements. No postoperative arrhythmia was observed.

  6. Papillary fibroelastoma of the anterior leaflet of the mitral valve mimicking vegetation

    PubMed Central

    Prifti, Edvin; Ademaj, Fadil; Ikonomi, Majlinda; Demiraj, Aurel

    2015-01-01

    The papillary fibroelastoma (PFE) is a rare and benign primary cardiac tumor, and the most frequently found tumor occurring in the cardiac valves. With the introduction of echocardiography, the diagnosis of these tumors in living patients has been reported sporadically. The PFEs have been found most often on valve leaflets, chordae tendineae, and both ventricles. We describe an interesting case of the PFE originating from the anterior leaflet of the mitral valve mimicking vegetation. The patient underwent successful surgical removal of the PFE. PMID:26187170

  7. Initial experience of mitral valve replacement with total preservation of both valve leaflets.

    PubMed Central

    Dottori, V; Barberis, L; Lijoi, A; Giambuzzi, M; Maccario, M; Faveto, C

    1994-01-01

    We compared a series of 7 consecutive patients who underwent mitral valve replacement with preservation of both leaflets to a control group of 97 patients who underwent standard mitral valve replacement at our institution during the same period. Use of inotropic drugs and duration of postoperative intensive care were compared and shown to be markedly reduced in the study group; however, statistical analysis was not applied due to the small number of patients. Comparison of the available pre- and postoperative echocardiographic values showed a decrease in left ventricular end-diastolic and end-systolic diameters in patients with preserved leaflets, particularly in those with mitral regurgitation of degenerative origin. PMID:8000269

  8. Infective Endocarditis of the Aortic Valve with Anterior Mitral Valve Leaflet Aneurysm.

    PubMed

    Tomsic, Anton; Li, Wilson W L; van Paridon, Marieke; Bindraban, Navin R; de Mol, Bas A J M

    2016-08-01

    Mitral valve leaflet aneurysm is a rare and potentially devastating complication of aortic valve endocarditis. We report the case of a 48-year-old man who had endocarditis of the native aortic valve and a concomitant aneurysm of the anterior mitral valve leaflet. Severe mitral regurgitation occurred after the aneurysm perforated. The patient showed no signs of heart failure and completed a 6-week regimen of antibiotic therapy before undergoing successful aortic and mitral valve replacement. In addition to the patient's case, we review the relevant medical literature.

  9. Rest perfusion abnormalities in hypertrophic cardiomyopathy: correlation with myocardial fibrosis and risk factors for sudden cardiac death.

    PubMed

    Chiribiri, A; Leuzzi, S; Conte, M R; Bongioanni, S; Bratis, K; Olivotti, L; De Rosa, C; Lardone, E; Di Donna, P; Villa, A D M; Cesarani, F; Nagel, E; Gaita, F; Bonamini, R

    2015-05-01

    To measure the prevalence of abnormal rest perfusion in a population of consecutive patients with known hypertrophic cardiomyopathy (HCM) referred for cardiovascular MRI (CMR), and to assess any associations between abnormal rest perfusion and the presence, pattern, and severity of myocardial scar and the presence of risk factors for sudden death. Eighty consecutive patients with known HCM referred for CMR underwent functional imaging, rest first-pass perfusion, and late gadolinium enhancement (LGE). Thirty percent of the patients had abnormal rest perfusion, all of them corresponding to areas of mid-myocardial LGE and to a higher degree of segmental hypertrophy. Rest perfusion abnormalities correlated with more extensive and confluent LGE. The subgroup of patients with myocardial fibrosis and rest perfusion abnormalities (fibrosis+/perfusion+) had more than twice the incidence of episodes of non-sustained ventricular tachycardia on Holter monitoring in comparison to patients with myocardial fibrosis and normal rest perfusion (fibrosis+/perfusion-) and patients with no fibrosis and normal rest perfusion (fibrosis-/perfusion-). First-pass perfusion CMR identifies abnormal rest perfusion in a significant proportion of patients with HCM. These abnormalities are associated with the presence and distribution of myocardial scar and the degree of hypertrophy. Rest perfusion abnormalities identify patients with increased incidence of episodes of non-sustained ventricular tachycardia on Holter monitoring, independently from the presence of myocardial fibrosis. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  10. Perfusion abnormalities in hemimegalencephaly.

    PubMed

    Wintermark, P; Roulet-Perez, E; Maeder-Ingvar, M; Moessinger, A C; Gudinchet, F; Meuli, R

    2009-04-01

    Cerebrovascular changes are rarely discussed in patients with hemimegalencephaly. These alterations have previously been associated with epileptical activity. We report the case of a 36-week gestation neonate presenting with total right hemimegalencephaly, as demonstrated by a magnetic resonance imaging (MRI) performed in the first days of life. Perfusion-weighted imaging displayed a clear hypervascularization of the right hemisphere. Diffusion-tensor imaging showed an arrangement of white matter fibers concentrically around the ventricle on the right hemisphere. AngioMRI showed an obvious asymmetry in the size of the middle cerebral arteries, with the right middle cerebral artery being prominent. The baby was free of clinical seizures during his first week of life. An electroencephalogram at that time displayed an asymmetric background activity, but no electrical seizures. Perfusion anomalies in hemimegalencephaly may not necessarily be related to epileptical activity, but may be related to vessel alterations. (c) Georg Thieme Verlag KG Stuttgart, New York.

  11. Package leaflets of the most consumed medicines in Portugal: safety and regulatory compliance issues. A descriptive study.

    PubMed

    Pires, Carla; Vigário, Marina; Cavaco, Afonso

    2015-01-01

    Package leaflets are necessary for safe use of medicines. The aims of the present study were: 1) to assess the compliance between the content of the package leaflets and the specifications of the pharmaceutical regulations; and 2) to identify potential safety issues for patients. Qualitative descriptive study, involving all the package leaflets of branded medicines from the three most consumed therapeutic groups in Portugal, analyzed in the Department of Pharmacoepidemiology, School of Pharmacy, University of Lisbon. A checklist validated through an expert consensus process was used to gather the data. The content of each package leaflet in the sample was classified as compliant or non-compliant with compulsory regulatory issues (i.e. stated dosage and descriptions of adverse reactions) and optional regulatory issues (i.e. adverse reaction frequency, symptoms and procedures in cases of overdose). A total of 651 package leaflets were identified. Overall, the package leaflets were found to be compliant with the compulsory regulatory issues. However, the optional regulatory issues were only addressed in around half of the sample of package leaflets, which made it possible to identify some situations of potentially compromised drug safety. Ideally, the methodologies for package leaflet approval should be reviewed and optimized as a way of ensuring the inclusion of the minimum essential information for safe use of medicines.

  12. Simulation of self expanding transcatheter aortic valve in a realistic aortic root: implications of deployment geometry on leaflet deformation.

    PubMed

    Gunning, Paul S; Vaughan, Ted J; McNamara, Laoise M

    2014-09-01

    Self expanding Transcatheter Aortic Valve Replacements (TAVR) can conform to the geometry of the aortic annulus and the calcified leaflet complex, which may result in leaflet distortion and altered leaflet kinematics, but such changes have not yet been characterized. In this study we developed a computational model to investigate the deployment of a self expanding TAVR in a realistic aortic root model derived from multi-slice computed tomography (MSCT) images. We simulated TAVR crimping/deployment in realistic and idealized aortic root models, followed by diastolic loading of the TAVR leaflets in its final deployed configuration. The TAVR deployed in a realistic aortic root had increased peak loading in the commissural region of the leaflets compared to TAVRs under idealized circular deployment conditions (2.97 vs. 1.52 MPa). Furthermore, orientation of the TAVR in the asymmetric aortic annulus such that the commissures of the TAVR are aligned with the native valve commissures minimized the effect of TAVR stent distortion on peak stresses in the TAVR leaflets (2.97 vs. 2.35 MPa). We propose that preoperative planning of the orientation of the TAVR in the aortic root annulus might minimize the impact of potential stent distortion on leaflet function and may in turn increase long term leaflet durability.

  13. Detection of apoptosis through the lipid order of the outer plasma membrane leaflet.

    PubMed

    Darwich, Zeinab; Klymchenko, Andrey S; Kucherak, Oleksandr A; Richert, Ludovic; Mély, Yves

    2012-12-01

    Cell plasma membranes of living cells maintain their asymmetry, so that the outer leaflet presents a large quantity of sphingomyelin, which is critical for formation of ordered lipid domains. Here, a recently developed probe based on Nile Red (NR12S) was applied to monitor changes in the lipid order specifically at the outer leaflet of cell membranes. Important key features of NR12S are its ratiometric response exclusively to lipid order (liquid ordered vs. liquid disordered phase) and not to surface charge, the possibility of using it at very low concentrations (10-20nM) and the very simple staining protocol. Cholesterol extraction, oxidation and sphingomyelin hydrolysis were found to red shift the emission spectrum of NR12S, indicating a decrease in the lipid order at the outer plasma membrane leaflet. Remarkably, apoptosis induced by three different agents (actinomycin D, camptothecin, staurosporine) produced very similar spectroscopic effects, suggesting that apoptosis also significantly decreases the lipid order at this leaflet. The applicability of NR12S to detect apoptosis was further validated by fluorescence microscopy and flow cytometry, using the ratio between the blue and red parts of its emission band. Thus, for the first time, an environment-sensitive probe, sensitive to lipid order, is shown to detect apoptosis, suggesting a new concept in apoptosis sensing.

  14. Efficient replacement of plasma membrane outer leaflet phospholipids and sphingolipids in cells with exogenous lipids.

    PubMed

    Li, Guangtao; Kim, JiHyun; Huang, Zhen; St Clair, Johnna R; Brown, Deborah A; London, Erwin

    2016-12-06

    Our understanding of membranes and membrane lipid function has lagged far behind that of nucleic acids and proteins, largely because it is difficult to manipulate cellular membrane lipid composition. To help solve this problem, we show that methyl-α-cyclodextrin (MαCD)-catalyzed lipid exchange can be used to maximally replace the sphingolipids and phospholipids in the outer leaflet of the plasma membrane of living mammalian cells with exogenous lipids, including unnatural lipids. In addition, lipid exchange experiments revealed that 70-80% of cell sphingomyelin resided in the plasma membrane outer leaflet; the asymmetry of metabolically active cells was similar to that previously defined for erythrocytes, as judged by outer leaflet lipid composition; and plasma membrane outer leaflet phosphatidylcholine had a significantly lower level of unsaturation than phosphatidylcholine in the remainder of the cell. The data also provided a rough estimate for the total cellular lipids residing in the plasma membrane (about half). In addition to such lipidomics applications, the exchange method should have wide potential for investigations of lipid function and modification of cellular behavior by modification of lipids.

  15. The Design of a Smokefree Home Leaflet and Home Pack: A Guernsey Case Study

    ERIC Educational Resources Information Center

    Amey, Vidya

    2011-01-01

    Purpose: This paper aims to explore the beliefs and attitudes of young mothers in relation to smokefree homes and passive smoke in Guernsey, and to encourage them to contribute to the designing of a smokefree home leaflet and pack aimed at young mothers. Design/methodology/approach: Semi-structured interviews were conducted with 11 participants…

  16. Photosynthetic carbon metabolism in leaflets, stipules and tendrils of Pisum sativum L

    SciTech Connect

    Cote, R.; Grodzinski, B. )

    1990-05-01

    Gas exchange and photosynthetic carbon metabolism have been investigated for each of the dominant parts of the pea leaf (P. sativum) in a normal and a semi-leafless phenotype (cv. Improved Laxton's Progress, and cv. Curly, respectively). On a fresh weight basis, net photosynthesis of leaflets and stipules have similar rates, while in tendrils the rte is 40% lower. However, on a surface area basis, tendrils are only 5-10% less efficient photosynthetically when the area is corrected by a factor {pi}/2. Transpiration rates are similar for leaflets and stipules, but double for tendrils even though stomatal frequency on tendrils is reduced by 50%. Dark respiration is higher in tendrils than leaflets and stipules. Gas exchange is comparable in both cultivars. The early {sup 14}C-labelled products of stipules, leaflets and tendrils are similar in both phenotypes, however the tendrils clearly partition about 2-3 times more of the newly fixed {sup 14}CO{sub 2} into the amino acid fraction. These data will be discussed in relation to the anatomy and function of pea tendrils.

  17. The Design of a Smokefree Home Leaflet and Home Pack: A Guernsey Case Study

    ERIC Educational Resources Information Center

    Amey, Vidya

    2011-01-01

    Purpose: This paper aims to explore the beliefs and attitudes of young mothers in relation to smokefree homes and passive smoke in Guernsey, and to encourage them to contribute to the designing of a smokefree home leaflet and pack aimed at young mothers. Design/methodology/approach: Semi-structured interviews were conducted with 11 participants…

  18. Tetralogy of Fallot with restrictive ventricular septal defect by accessory tricuspid leaflet tissue.

    PubMed

    Soni, Mahipat Raj; Bohara, Deepak A; Mahajan, Ajay U; Nathani, Pratap J

    2012-01-01

    In tetralogy of Fallot septal defect is usually large because of malalignment of outlet septum, restrictive defect has been reported rarely. We present a case of tetralogy of Fallot with accessory tricuspid leaflet tissue restricting ventricular septal defect. The report includes echocardiographic and catheter images of this rare presentation of tetralogy of Fallot.

  19. Efficient replacement of plasma membrane outer leaflet phospholipids and sphingolipids in cells with exogenous lipids

    PubMed Central

    Kim, JiHyun; Huang, Zhen; St. Clair, Johnna R.; Brown, Deborah A.; London, Erwin

    2016-01-01

    Our understanding of membranes and membrane lipid function has lagged far behind that of nucleic acids and proteins, largely because it is difficult to manipulate cellular membrane lipid composition. To help solve this problem, we show that methyl-α-cyclodextrin (MαCD)-catalyzed lipid exchange can be used to maximally replace the sphingolipids and phospholipids in the outer leaflet of the plasma membrane of living mammalian cells with exogenous lipids, including unnatural lipids. In addition, lipid exchange experiments revealed that 70–80% of cell sphingomyelin resided in the plasma membrane outer leaflet; the asymmetry of metabolically active cells was similar to that previously defined for erythrocytes, as judged by outer leaflet lipid composition; and plasma membrane outer leaflet phosphatidylcholine had a significantly lower level of unsaturation than phosphatidylcholine in the remainder of the cell. The data also provided a rough estimate for the total cellular lipids residing in the plasma membrane (about half). In addition to such lipidomics applications, the exchange method should have wide potential for investigations of lipid function and modification of cellular behavior by modification of lipids. PMID:27872310

  20. Surgical technique: establishing a pre-clinical large animal model to test aortic valve leaflet substitute

    PubMed Central

    Knirsch, Walter; Cesarovic, Niko; Krüger, Bernard; Schmiady, Martin; Frauenfelder, Thomas; Frese, Laura; Dave, Hitendu; Hoerstrup, Simon Philipp; Hübler, Michael

    2016-01-01

    To overcome current limitations of valve substitutes and tissue substitutes the technology of tissue engineering (TE) continues to offer new perspectives in congenital cardiac surgery. We report our experiences and results implanting a decellularized TE patch in nine sheep in orthotropic position as aortic valve leaflet substitute. Establishing the animal model, feasibility, cardiopulmonary bypass issues and operative technique are highlighted. PMID:28149571

  1. Why Organizations Continue to Create Patient Information Leaflets with Readability and Usability Problems: An Exploratory Study

    ERIC Educational Resources Information Center

    Gal, Iddo; Prigat, Ayelet

    2005-01-01

    Readability and usability problems with patient information leaflets continue to be reported despite long-standing recognition of their existence and the availability of guidelines for developing health education materials. This exploratory study examined possible causes for such problems, based on interviews with professionals who developed…

  2. 27 CFR 4.38a - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Bottle cartons, booklets and leaflets. 4.38a Section 4.38a Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL LABELING AND ADVERTISING OF WINE Labeling...

  3. 27 CFR 4.38a - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Bottle cartons, booklets and leaflets. 4.38a Section 4.38a Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Labeling...

  4. 27 CFR 4.38a - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottle cartons, booklets and leaflets. 4.38a Section 4.38a Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Labeling...

  5. 27 CFR 4.38a - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Bottle cartons, booklets and leaflets. 4.38a Section 4.38a Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL LABELING AND ADVERTISING OF WINE Labeling...

  6. 27 CFR 4.38a - Bottle cartons, booklets and leaflets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Bottle cartons, booklets and leaflets. 4.38a Section 4.38a Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Labeling...

  7. Hypersensitive reactions to local dental anesthetics and patient information: critical review of a drug leaflet

    PubMed Central

    Simonet, Daniel

    2011-01-01

    This paper discusses the case of a patient who experienced adverse reactions to a local anesthetic. It reviews symptoms of adverse reactions, possible causes, patient management, and alternative anesthesia modes. The second part of the paper discusses the product leaflet information and the associated legal issues. PMID:22915891

  8. Systematic CT Methodology for the Evaluation of Subclinical Leaflet Thrombosis.

    PubMed

    Jilaihawi, Hasan; Asch, Federico M; Manasse, Eric; Ruiz, Carlos E; Jelnin, Vladimir; Kashif, Mohammad; Kawamori, Hiroyuki; Maeno, Yoshio; Kazuno, Yoshio; Takahashi, Nobuyuki; Olson, Richard; Alkhatib, Joe; Berman, Daniel; Friedman, John; Gellada, Norman; Chakravarty, Tarun; Makkar, Raj R

    2017-04-01

    Subclinical leaflet thrombosis was recently described in a randomized trial of transcatheter aortic valve replacement. It was subsequently demonstrated in a series of registries that this was a commonly observed imaging finding seen in all transcatheter and surgical bioprostheses. The phenomenon has aroused considerable interest due to the as-yet-undefined risk for later clinical events and the possibility of pharmacological intervention with anticoagulation. Subclinical leaflet thrombosis is easily detected noninvasively by technically suitable computed tomography (CT) with a high degree of concordance to transesophageal echocardiography findings. The CT hallmarks were noted to be hypoattenuated leaflet thickening (HALT) associated with reduced leaflet motion (RELM). The combination of HALT and RELM signified hypoattenuation affecting motion, the standardized imaging endpoint used. This paper describes the systematic CT evaluation methodology that was devised during the Portico trial investigation and U.S. Food and Drug Administration submission; it also highlights the need for an ongoing discussion among experts to enable, with the help of the Valve Academic Research Consortium, standardization of reporting of this imaging finding to cater to the present and future needs of clinical trials.

  9. Teenage Pregnancy: An Intensive and Critical Problem in Search of a Solution. Student Fact Finder Leaflet.

    ERIC Educational Resources Information Center

    Glover-Smith, Alma

    This document presents materials from a course designed to teach adolescents about teenage pregnancy and parenting. The materials are organized into nine modules, each of which contains instructions on how to use the module; a pre- and post-test on the information presented in the module; a fact finder leaflet of information; and relevant…

  10. A study of the pulsatile flow and its interaction with rectangular leaflets

    NASA Astrophysics Data System (ADS)

    Ledesma, Rene; Zenit, Roberto; Pulos, Guillermo

    2009-11-01

    To avoid the complexity and limited understanding of the 3D pulsatile flow field through heart valves, a cardiac-like flow circuit and a test channel were designed to study the behavior of bidimensional leaflets made of hyperelastic materials. We study a simple 2D arrangement to understand the basic physics of the flow-leaflet interaction. Creating a periodic pressure gradient, measurements of leaflet deflection were obtained for different flow conditions, geometries and materials. Using PIV and Phase Locking techniques, we have obtained the leaflet motion and the time-dependent flow velocity fields. The results show that two dimensionless parameters determine the performance of a simple bi-dimensional valve, in accordance with the flow conditions applied: π1=f(sw)^1/2(E/ρ)^1/2 and π2=V/(2slw), where f is the pulsation frequency, V is the stroke volume, s, w and l are the dimensions on the leaftlet and E and ρ are the elastic modulus and density of the material, respectively. Furthermore, we have identified the conditions for which the fluid stresses can be minimized. With these results we propose a new set of parameters to improve the performance of prosthetic heart valves and, in consequence, to reduce blood damage.

  11. Perfusion Based Cell Culture Chips

    NASA Astrophysics Data System (ADS)

    Heiskanen, A.; Emnéus, J.; Dufva, M.

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers.

  12. Thallium-201 scintigraphy perfusion defect with dipyridamole in a patient with a myocardial bridge

    SciTech Connect

    Bennett, J.M.; Blomerus, P.

    1988-04-01

    A patient with myocardial bridging and a thallium-201 scintigraphy perfusion defect after the administration of intravenous dipyridamole is presented. The same patient had a normal perfusion study on exercise stress testing. The effects of coronary vasodilators and dipyridamole on coronary artery flow patterns in patients with myocardial bridging are discussed. We suggest that coronary vasodilators may induce perfusion defects in patients with myocardial bridging and should be avoided in such patients.

  13. Hemocompatibility and Hemodynamics of Novel Hyaluronan–Polyethylene Materials for Flexible Heart Valve Leaflets

    PubMed Central

    Prawel, David A.; Dean, Harold; Forleo, Marcio; Lewis, Nicole; Gangwish, Justin; Popat, Ketul C.; DASI, Lakshmi Prasad; James, Susan P.

    2013-01-01

    Polymeric heart valves (PHVs) hold the promise to be more durable than bioprosthetic heart valves and less thrombogenic than mechanical heart valves. We introduce a new framework to manufacture hemocompatible polymeric leaflets for HV (PHV) applications using a novel material comprised of interpenetrating networks (IPNs) of hyaluronan (HA) and linear low density polyethylene (LLDPE). We establish and characterize the feasibility of the material as a substitute leaflet material through basic hemodynamic measurements in a trileaflet configuration, in addition to demonstrating superior platelet response and clotting characteristics. Plain LLDPE sheets were swollen in a solution of silylated-HA, the silylated-HA was then crosslinked to itself before it was reverted back to native HA via hydrolysis. Leaflets were characterized with respect to (1) bending stiffness, (2) hydrophilicity, (3) whole blood clotting, and (4) cell (platelet and leukocyte) adhesion under static conditions using fresh human blood. In vitro hemodynamic testing of prototype HA/LLDPE IPN PHVs was used to assess feasibility as functional HVs. Bending stiffness was not significantly different from natural fresh leaflets. HA/LLDPE IPNs were more hydrophilic than LLDPE controls. HA/LLDPE IPNs caused less whole blood clotting and reduced cell adhesion compared to the plain LLDPE control. Prototype PHVs made with HA/LLDPE IPNs demonstrated an acceptable regurgitation fraction of 4.77 ± 0.42%, and effective orifice area in the range 2.34 ± 0.5 cm2. These results demonstrate strong potential for IPNs between HA and polymers as future hemocompatible HV leaflets. Further studies are necessary to assess durability and calcification resistance. PMID:24729797

  14. Nitric-oxide inhibits nyctinastic closure through cGMP in Albizia lophantha leaflets.

    PubMed

    Bergareche, Carmen; Moysset, Luisa; Angelo, Alcira Paola; Chellik, Samira; Simón, Esther

    2014-09-01

    Nitric oxide (NO) is a highly reactive radical that acts as a direct or indirect cellular signalling molecule in plant growth, development and environmental responses. Here we studied the contribution of NO to the control of leaflet movements during nyctinastic closure. For this purpose, we tested the effect of NO donors and an NO scavenger, all supplied in light, on Albizia lophantha leaflet closure after transferral to darkness. Exogenous NO, applied as four donors [sodium nitroprusside (SNP), diethylammonium (Z)-1-(N,N-diethylamino) diazen-1-ium-1,2-diolate (DEA-NONOate), S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GS-NO)], inhibited nyctinastic leaflet closure while the application of an NO scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO)] plus SNP cancelled the effect of the latter. The inclusion of Nω-nitro-l-arginine methyl ester (l-NAME) or sodium tungstate in the incubation media enhanced nyctinastic closure and also resulted in a decrease in the nitrate plus nitrite released by leaflets into the incubation solution. These results support the notion that NO is involved in regulating the nyctinastic closure of A. lophantha leaflets. Cellular perception of NO did not appear to be mediated by calcium. Pharmacological application of inhibitors of soluble guanylate cyclase (sGC) [1H-[1,2,4]-oxadiazole-[4,3-a]-quinoxalin-1-one (ODQ) and 6-anilino-5,8-quinolinequinone (Ly83583)], phosphodiesterase type 5 (PDE5) (Sildenafil) and the cyclic guanosine monophosphate (cGMP) analogue 8-bromoguanosine-3',5'-cyclomonophosphate sodium salt (8-Br-cGMP) indicated that cGMP was downstream of the NO signalling cascade during nyctinastic closure.

  15. Experimental measurement of dynamic fluid shear stress on the ventricular surface of the aortic valve leaflet

    PubMed Central

    Yap, Choon Hwai; Saikrishnan, Neelakantan

    2015-01-01

    Aortic valve (AV) calcification is a highly prevalent disease with serious impact on mortality and morbidity. The exact causes and mechanisms of AV calcification are unclear, although previous studies suggest that mechanical forces play a role. It has been clinically demonstrated that calcification preferentially occurs on the aortic surface of the AV. This is hypothesized to be due to differences in the mechanical environments on the two sides of the valve. It is thus necessary to characterize fluid shear forces acting on both sides of the leaflet to test this hypothesis. The current study is one of two studies characterizing dynamic shear stress on both sides of the AV leaflets. In the current study, shear stresses on the ventricular surface of the AV leaflets were measured experimentally on two prosthetic AV models with transparent leaflets in an in vitro pulsatile flow loop using two-component Laser Doppler Velocimetry (LDV). Experimental measurements were utilized to validate a theoretical model of AV ventricular surface shear stress based on the Womersley profile in a straight tube, with corrections for the opening angle of the valve leaflets. This theoretical model was applied to in vivo data based on MRI-derived volumetric flow rates and valve dimension obtained from the literature. Experimental results showed that ventricular surface shear stress was dominated by the streamwise component. The systolic shear stress waveform resembled a half-sinusoid during systole and peaks at 64–71 dyn/cm2, and reversed in direction at the end of systole for 15–25 ms, and reached a significant negative magnitude of 40–51 dyn/cm2. Shear stresses from the theoretical model applied to in vivo data showed that shear stresses peaked at 77–92 dyn/cm2 and reversed in direction for substantial period of time (108–110 ms) during late systole with peak negative shear stress of 35–38 dyn/cm2. PMID:21465260

  16. Extracellular matrix remodeling in wound healing of critical size defects in the mitral valve leaflet.

    PubMed

    Stephens, Elizabeth H; Nguyen, Tom C; Blazejewski, Jack G; Vekilov, Dragoslava P; Connell, Jennifer P; Itoh, Akinobu; Ingels, Neil B; Miller, D Craig; Grande-Allen, K Jane

    2016-07-01

    The details of valvular leaflet healing following valvuloplasty and leaflet perforation from endocarditis are poorly understood. In this study, the synthesis and turnover of valvular extracellular matrix due to healing of a critical sized wound was investigated. Twenty-nine sheep were randomized to either CTRL (n = 11) or HOLE (n = 18), in which a 2.8-4.8 mm diameter hole was punched in the posterior mitral leaflet. After 12 weeks, posterior leaflets were harvested and histologically stained to localize extracellular matrix components. Immunohistochemistry was also performed to assess matrix components and markers of matrix turnover. A semi-quantitative grading scale was used to quantify differences between HOLE and CTRL. After 12 weeks, the hole diameter was reduced by 71.3 ± 1.4 % (p < 0.001). Areas of remodeling surrounding the hole contained more activated cells, greater expression of proteoglycans, and markers of matrix turnover (prolyl 4-hydroxylase, metalloproteases, and lysyl oxidase, each p ≤ 0.025), along with fibrin accumulation. Two distinct remodeling regions were evident surrounding the hole, one directly bordering the hole rich in versican and hyaluronan and a second adjacent region with abundant collagen and elastic fiber turnover. The remodeling also caused reduced delineation between valve layers (p = 0.002), more diffuse staining of matrix components and markers of matrix turnover (p < 0.001), and disruption of the collagenous fibrosa. In conclusion, acute valve injury elicited distinct, heterogeneous alterations in valvular matrix composition and structure, resulting in partial wound closure. Because these changes could also affect leaflet mechanics and valve function, it will be important to determine their impact on healing wounds.

  17. Home delivery of medication - the role of a patient information leaflet on maximising service uptake.

    PubMed

    Watson, L; Ahmed, N; Mccall, H; Minton, J; Benn, P; Edwards, S; Waters, L

    2014-12-01

    There are currently over 30,000 HIV-positive individuals in London and over 25,000 on anti-retroviral therapy. In 2009/2010, this equated to £170m spent by London's NHS on anti-retroviral drugs. Ways employed to reduce this cost include standardising the drugs patients are on and delivering medication to patients at home. Home delivery (HD) medication is exempt from value-added tax. The savings made from 10 patients using the home delivery service would free up resources to provide anti-retroviral therapy to one further patient. Studies have shown that concerns surrounding potential breaches of confidentiality are a potential barrier to some people using the home delivery service. In order to challenge these concerns, a leaflet was devised highlighting the major benefits to both the patient and the NHS of home delivery and addressing concerns over confidentiality. The leaflet was handed out to patients at the Mortimer Market Centre who were currently on anti-retroviral medication but not on home delivery. They were asked to complete a survey on their views of the service before and after reading the leaflet, whether they had been previously aware of the service and whether their concerns had been addressed. Some 79% felt that the patient information leaflet addressed all of their concerns, and it helped 11% decide whether to consider using home delivery. However, as more patients were opposed to the service after reading the patient information leaflet than those considering it, more work needs to be done to explore patients' concerns and other factors influencing home delivery service uptake. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  18. EFFECTS OF DECELLULARIZATION ON THE MECHANICAL AND STRUCTURAL PROPERTIES OF THE PORCINE AORTIC VALVE LEAFLET

    PubMed Central

    Liao, Jun; Joyce, Erinn M.; Sacks, Michael S.

    2008-01-01

    The potential for decellularized aortic heart valves (AVs) as heart valve replacements is based on the assumption that the major cellular immunogenic components have been removed, and that the remaining extracellular matrix (ECM) should retain the necessary mechanical properties and functional design. However, decellularization processes likely alter the ECM mechanical and structural properties, potentially affecting long term durability. In the present study we explored the effects of an anionic detergent (SDS), enzymatic agent (Trypsin), and a non-ionic detergent (Triton X-100) on the mechanical and structural properties of AV leaflets (AVLs) to provide greater insight into the initial functional state of the decellularized AVL. The overall extensibility represented by the areal strain under 60 N/m increased from 68.85% for the native AV to 139.95%, 137.51%, and 177.69% for SDS, Trypsin, and Triton X-100, respectively, after decellularization. In flexure, decellularized AVLs demonstrated a profound loss of stiffness overall, and also produced a nonlinear moment-curvature relation compared to the linear response of the native AVL. Effective flexural moduli decreased from 156.0±24.6 kPa for the native AV to 23.5±5.8 kPa, 15.6±4.8 kPa, and 19.4±8.9 kPa for SDS, Trypsin, and Triton X-100 treated leaflets, respectively. While the overall leaflet fiber architecture remained relatively unchanged, decellularization resulted in substantial microscopic disruption. In conclusion, changes in mechanical and structural properties of decellularized leaflets were likely associated with disruption of the ECM, which may impact the durability of the leaflets. PMID:18096223

  19. Diel Variation in Population Size and Ice Nucleation Activity of Pseudomonas syringae on Snap Bean Leaflets.

    PubMed

    Hirano, S S; Upper, C D

    1989-03-01

    The extent to which diel changes in the physical environment affect changes in population size and ice nucleation activity of Pseudomonas syringae on snap bean leaflets was determined under field conditions. To estimate bacterial population size and ice nucleation activity, bean leaflets were harvested at 2-h intervals during each of three 26-h periods. A tube nucleation test was used to assay individual leaflets for ice nuclei. Population sizes of P. syringae were determined by dilution plating of leaflet homogenates. The overall diel changes in P. syringae population sizes differed during each of the 26-h periods. In one 26-h period, there was a continuous increase in the logarithm of P. syringae population size despite intense solar radiation, absence of free moisture on leaf surfaces, and low relative humidity during the day. A mean doubling time of approximately 4.9 h was estimated for the 28-fold increase in P. syringae population size that occurred from 0900 to 0900 h during the 26-h period. However, doubling times of 3.3 and 1.9 h occurred briefly during this period from 1700 to 2300 h and from 0100 to 0700 h, respectively. Thus, growth rates of P. syringae in association with leaves in the field were of the same order of magnitude as optimal rates measured in the laboratory. The frequency with which leaflets bore ice nuclei active at -2.0, -2.2, and -2.5 degrees C varied greatly within each 26-h period. These large diel changes were inversely correlated primarily with the diel changes in air temperature and reflected changes in nucleation frequency rather than changes in population size of P. syringae. Thus, the response of bacterial ice nucleation activity to the physical environment was distinct from the changes in population size of ice nucleation-active P. syringae.

  20. Development and Validation of Educational Leaflet for Caregivers of Preterm Infants

    PubMed Central

    Khurana, Sonia; Rao, Bhamini Krishna; Lewis, Leslie Edward S.; Bhat, Ramesh; Purkayastha, Jayashree; Kamath, Asha

    2016-01-01

    Introduction Facilitation of child development is usually emphasized in the form of early intervention classes and practical demonstrations. However, non-adherence to home program for such interventions has been reported due to various reasons. Aim To develop and validate an educational leaflet as a supplement guide for caregivers to promote better development of their child during 4-6 months of age. Materials and Methods An in-depth literature review and focus group discussion with the experts was conducted to formulate the content of leaflet. Initial framework consisted of introduction, main text with pictorial representation and instructions about facilitation of various milestones, do’s–don’ts and disclaimer. Validation was done through a questionnaire consisting of 9 questions pertaining to completeness, understandability, legibility, clarity and utility of educational material for caregivers and a section for comments. Leaflet with enclosed questionnaire was distributed to 14 validators (2 neonatologists, 4 paediatricians and 8 physiotherapists), along with a covering letter stating the purpose and relevance of this educational material, and the importance of their participation in validation process. Scoring was done on 5 point Likert scale for each item in the material. Results Responses from the 14 evaluators were collected and analysed. Item level content validity index (I-CVI) was calculated for individual items which ranged from 0.73 – 1. Scale level Content Validity Index (S-CVI) was calculated for complete nine items and it was found to be 0.91. Validators expressed their views to include a column on normal milestones across 4-6 months of age and also to highlight the significance of performing each activity mentioned in the leaflet. These suggestions were incorporated in consensus with the subject experts and the final draft was made. Conclusion Educational leaflet for caregivers of 4-6 months preterm infants has been developed and validated

  1. Comparison of the occurrence of thromboembolic and bleeding complications in patients with mechanical heart valve prosthesis with one and two leaflets in the mitral position

    PubMed Central

    de Campos, Nelson Leonardo Kerdahi Leite

    2014-01-01

    Introduction Patients with mechanical heart valve prostheses must continuously be treated with oral anticoagulants to prevent thromboembolic events related to prosthetesis. These patients should be continually evaluated for the control of oral anticoagulation. Objective To compare the occurrence of thromboembolic and hemorragic complications in patients with mechanical heart valve prosthesis with one (mono) and two (bi) leaflets in the mitral position in anticoagulant therapy. Methods We studied the 10-year interval, 117 patients with prosthesis in the mitral position, 48 with prosthetic single leaflet and 69 with two leaflets. We evaluated the occurrence of thromboembolic and hemorrhagic major and minor degree under gravity. The results are presented in an actuarial study and the frequency of occurrence of linear events. Results The actuarial survival curves showed that over time, patients with prosthetic heart valve with one leaflet were less free of thromboembolic complications than patients with two leaflet prosthetic valve, while the latter (two leaflet) were less free of hemorrhagic accidents. The linearized frequency of occurrence of thromboembolism were higher in patients with mono leaflet prosthesis. Bleeding rates were higher for patients with bi leaflet prosthetic valve. Conclusion Patients with mono leaflet prosthetic heart valve showed that they are more prone to the occurrence of serious thromboembolic events compared to those with bi leaflet prosthetic valve. Patients with bi leaflet prosthetic valve had more bleeding than patients with mono leaflet prosthetic valve, however this difference was restricted to the bleeding of minor nature. PMID:24896164

  2. Perfusion Bioreactor Module

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R.

    1990-01-01

    Perfusion bioreactor module, self-contained, closed-loop cell-culture system that operates in microgravity or on Earth. Equipment supports growth or long-term maintenance of cultures of human or other fragile cells for experiments in basic cell biology or process technology. Designed to support proliferation (initially at exponential rates of growth) of cells in complex growth medium and to maintain confluent cells in defined medium under conditions optimized to permit or encourage selected functions of cells, including secretion of products of cells into medium.

  3. [Medication leaflets used by elderly with hypertension: adequacy of information for sanitary regulation and possible implications for health].

    PubMed

    de Lyra Junior, Divaldo Pereira; Balisa-Rocha, Blície Jennifer; Mesquita, Alessandra Resende; da Rocha, Chiara Ermínia

    2010-09-01

    The medication leaflets represent the main source of written information supplied to the patients, in special to the elderly. This study aimed to analyze the content of the leaflets of drugs often prescribed for elderly people with hypertension, as well as their adequacy to the sanitary regulations and possible health implications. A descriptive study was conducted in two stages: A, in July 2002, and B, in July 2007. In each stage were analyzed 34 medication leaflets of seven antihypertensive drugs of the National Essential Drugs List (2006). Among the 68 leaflets analyzed, most did not contain all the information required by Portaria nº 110/1997 (89.5%) in the stage A and the RDC nº 140/2003 (100%) in B. In 100% of the leaflets, the legislation had not been fulfilled. Some important topics as way of administration, how to use and overdose had been absent in 76% of the leaflets, the lack of this information has an impact in the security of the antihypertensive users. Based on these data, it was possible to evidence inadequate contents of the medication leaflets. So, it is necessary greater surveillance by Anvisa, to ensure the rational use of medicines and the reduction of the risks to the elderly health.

  4. Simplifying drug package leaflets written in Spanish by using word embedding.

    PubMed

    Segura-Bedmar, Isabel; Martínez, Paloma

    2017-09-29

    Drug Package Leaflets (DPLs) provide information for patients on how to safely use medicines. Pharmaceutical companies are responsible for producing these documents. However, several studies have shown that patients usually have problems in understanding sections describing posology (dosage quantity and prescription), contraindications and adverse drug reactions. An ultimate goal of this work is to provide an automatic approach that helps these companies to write drug package leaflets in an easy-to-understand language. Natural language processing has become a powerful tool for improving patient care and advancing medicine because it leads to automatically process the large amount of unstructured information needed for patient care. However, to the best of our knowledge, no research has been done on the automatic simplification of drug package leaflets. In a previous work, we proposed to use domain terminological resources for gathering a set of synonyms for a given target term. A potential drawback of this approach is that it depends heavily on the existence of dictionaries, however these are not always available for any domain and language or if they exist, their coverage is very scarce. To overcome this limitation, we propose the use of word embeddings to identify the simplest synonym for a given term. Word embedding models represent each word in a corpus with a vector in a semantic space. Our approach is based on assumption that synonyms should have close vectors because they occur in similar contexts. In our evaluation, we used the corpus EasyDPL (Easy Drug Package Leaflets), a collection of 306 leaflets written in Spanish and manually annotated with 1400 adverse drug effects and their simplest synonyms. We focus on leaflets written in Spanish because it is the second most widely spoken language on the world, but as for the existence of terminological resources, the Spanish language is usually less prolific than the English language. Our experiments show an

  5. A qualitative study of Telehealth patient information leaflets (TILs): are we giving patients enough information?

    PubMed

    Kayyali, Reem; Hesso, Iman; Ejiko, Evelyn; Nabhani Gebara, Shereen

    2017-05-19

    The provision of patient information leaflets regarding telehealth has been perceived by potential consumers as a strategy to promote awareness and adoption of telehealth services. However, such leaflets need to be designed carefully if adoption and awareness among potential users is to be promoted. Therefore, the aims of this study were: first, to see how telehealth was portrayed in some of the existing telehealth leaflets (THLs). Second, to explore patients' perceptions of the existing THLs and their engagement with the concept and how THLs can be optimised. A two-step approach was employed to address the aims of this study. The first phase involved the use of discourse analysis to compare 12 electronically and publically available THLs, with the existing THL guidance "Involve Yorkshire and Humber". The second phase involved conducting 14 semi-structured interviews with potential telehealth users/patients to gauge their perception and engagement with the concept, using the two leaflets that were mostly matching with the guidance used. Six interviews were audio-recorded and eight had detailed jotted notes. The interviews were transcribed and thematically analysed to identify key themes. The discourse analysis showed certain gaps and variations within the screened leaflets when addressing the following aspects: cost of the telehealth service, confidentiality, patients' choices in addition to equipment use and technical support. Analysis of the interviews revealed patients' need for having clear and sufficient information about the telehealth service within the THLs; in addition to, patients' preference for the use of simpler terminologies for telehealth description and the provision of clear simple texts with pictorial presentations. The interviews also revealed certain limitations against adoption of telehealth by the participants, such as: lack of privacy and confidentiality of information, fear of technology breakdown and equipment failure, loss of face

  6. Engineering tissue constructs to mimic native aortic and pulmonary valve leaflets' structures and mechanics

    NASA Astrophysics Data System (ADS)

    Masoumi, Nafiseh

    There are several disadvantages correlated with current heart valve replacement, including anticoagulation therapy for patients with mechanical valves and the low durability of bioprosthetic valves. The non-viable nature of such devices is a critical drawback especially for pediatric cases due to the inability of the graft to grow in vivo with the patients. A tissue engineered heart valve (TEHV) with remodeling and growth ability, is conceptually appealing to use in the surgical repair and could serve as a permanent replacements when operating for pediatric valvular lesions. It is critical that scaffolds for functional heart valve tissue engineering, be capable of mimicking the native leaflet's structure and mechanical properties at the time of implantation. Meanwhile, the scaffolds should be able to support cellular proliferation and native-like tissue formation as the TEHV remodels toward a scaffold-free state. Our overall hypothesis is that an "ideal" engineered construct, designed based on native leaflet's structure and mechanics, will complement a native heart valve leaflet in providing benchmarks for use in the design of clinically-applicable TEHV. This hypothesis was addressed through several experiments conducted in the present study. To establish a functional biomimetic TEHV, we developed scaffolds capable of matching the anisotropic stiffness of native leaflet while promoting native-like cell and collagen content and supporting the ECM generation. Scaffolds with various polymer contents (e.g., poly (glycerol sebacate) (PGS) and poly (epsilon-caprolactone) (PCL)) and structural designs (e.g., microfabricated and microfibrous scaffolds), were fabricated based on native leaflet's structure and mechanics. It was found that the tri-layered scaffold, designed with assembly of microfabricated PGS and microfibrous PGS/PCL was a functional leaflet capable of promoting tissue formation. Furthermore, to investigate the effect of cyclic stress and flexure

  7. Harmonic analysis of perfusion pumps.

    PubMed

    Dougherty, F Carroll; Donovan, F M; Townsley, Mary I

    2003-12-01

    The controversy over the use of nonpulsatile versus pulsatile pumps for maintenance of normal organ function during ex vivo perfusion has continued for many years, but resolution has been limited by lack of a congruent mathematical definition of pulsatility. We hypothesized that the waveform frequency and amplitude, as well as the underlying mean distending pressure are all key parameters controlling vascular function. Using discrete Fourier Analysis, our data demonstrate the complexity of the pulmonary arterial pressure waveform in vivo and the failure of commonly available perfusion pumps to mimic in vivo dynamics. In addition, our data show that the key harmonic signatures are intrinsic to the perfusion pumps, are similar for flow and pressure waveforms, and are unchanged by characteristics of the downstream perfusion circuit or perfusate viscosity.

  8. Glomerular effects of AVT on the in situ perfused trunk preparation of the dogfish.

    PubMed

    Wells, Alan; Anderson, W Gary; Hazon, Neil

    2005-04-01

    The effects of arginine vasotocin on the pattern of glomerular perfusion in an elasmobranch fish were examined using an in situ perfused renal trunk preparation. A significant antidiuresis was coupled with a marked reduction in the proportion of filtering glomeruli (86%-25%) and an increase in the proportion of perfused but not filtering (10%-53%) and non-perfused glomeruli (4%-22%). However, the reduction in filtering glomeruli was greater than predicted by measurements of urine flow rate and glomerular filtration rate alone, suggesting that alterations in single nephron glomerular filtration rate may occur.

  9. The bioclimatological leaflet as a means conveying climatological information to tourists and the tourism industry

    NASA Astrophysics Data System (ADS)

    Zaninović, Ksenija; Matzarakis, Andreas

    2009-07-01

    Climate is an important resource for tourism and must be taken into account in tourism promotions. Here, a climate leaflet containing climatological and bioclimatological information for tourists is presented. The bioclimatological conditions are portrayed using mean values and frequency of thermal sensation based on physiologically equivalent temperature for 10-day intervals covering the whole year, along with air and sea temperature, sunshine duration, amount and number of days with precipitation and wind roses. In addition, the Climate Tourism Information Scheme is included. When combined with climatological and bioclimatological conditions, this scheme is valuable for tourists as it enables them to choose the most suitable time period for holidays, with the choice depending on personal preferences and requirements. The information provided here assists the tourism industry and stakeholders in decision-making. As an example, the bioclimatological leaflet for Hvar, an island off the Croatian Adriatic coast, is presented.

  10. Detection of cholesterol-rich microdomains in the inner leaflet of the plasma membrane

    SciTech Connect

    Hayashi, Masami; Shimada, Yukiko; Inomata, Mitsushi; Ohno-Iwashita, Yoshiko . E-mail: iwashita@tmig.or.jp

    2006-12-22

    The C-terminal domain (D4) of perfringolysin O binds selectively to cholesterol in cholesterol-rich microdomains. To address the issue of whether cholesterol-rich microdomains exist in the inner leaflet of the plasma membrane, we expressed D4 as a fusion protein with EGFP in MEF cells. More than half of the EGFP-D4 expressed in stable cell clones was bound to membranes in raft fractions. Depletion of membrane cholesterol with {beta}-cyclodextrin reduced the amount of EGFP-D4 localized in raft fractions, confirming EGFP-D4 binding to cholesterol-rich microdomains. Subfractionation of the raft fractions showed most of the EGFP-D4 bound to the plasma membrane rather than to intracellular membranes. Taken together, these results strongly suggest the existence of cholesterol-rich microdomains in the inner leaflet of the plasma membrane.

  11. Leaflet anatomy verifies relationships within Syagrus (Arecaceae) and aids in identification

    PubMed Central

    Noblick, Larry R.

    2013-01-01

    Abstract The current investigation was carried out to examine how palm anatomy may coincide with the current molecular analysis including the three recognized clades of Syagrus Mart. and to justify the splitting of acaulescent Syagrus species (e.g. Syagrus petraea (Mart.) Becc.) into several species. Free-hand cross-sections of leaflets were made and the comparison of these verifies the relationships suggested by the molecular data. Free-hand leaflet sections were also found to be useful in the identification of otherwise difficult-to-identify acaulescent Syagrus species. The result and conclusion is that anatomical data is valuable in helping to verify molecular data and that splitting the acaulescent species of Syagrus is justified by the differences discovered in their field habit and anatomy. These differences were used to produce an identification key that is based on the anatomy. PMID:24194671

  12. Effect of Light Intensity during Growth on Photoinhibition of Intact Attached Bean Leaflets.

    PubMed

    Powles, S B; Critchley, C

    1980-06-01

    In the study reported here, two different photoinhibitory phenomena were compared within a single plant species. Bean plants were grown in three different light intensities to simulate sun and shade environments. The effects of photoinhibitory treatments on in vivo CO(2) assimilation rates and in vitro chloroplast electron transport reactions were investigated and the extent to which carbon metabolism served to prevent photoinhibition was characterized. It was shown that the photoinhibition which follows exposure of intact leaflets of low light-grown bean plants to high light intensity in normal air is essentially similar to that which occurs when leaflets of plants grown in full sunlight are illuminated in the absence of CO(2) at low O(2) partial pressures.

  13. The surface microstructure of cusps and leaflets in rabbit and mouse heart valves

    PubMed Central

    Ye, Xia; Zhou, Ming; Lei, Weining

    2014-01-01

    Summary In this investigation, scanning electron microscopy was used to characterize the microstructure on the surfaces of animal heart valve cusps/leaflets. The results showed that though these surfaces appear smooth to the naked eye, they are actually comprised of a double hierarchical structure consisting of a cobblestone-like microstructure and nano-cilia along with mastoids with a directional arrangement. Such nanostructures could play a very important role in the hemocompatibility characteristics of heart valves. On this basis, the model of the microstructure was constructed and theoretical analysis was used to obtain optimal geometric parameters for the rough surface of artificial valve cusps/leaflets. This model may help improve reconstructive techniques and it may be beneficial in the design and fabrication of valve substitutes or partial substitutes. Namely, the model may help ameliorate heart valve replacement surgery. PMID:24991498

  14. A meso-scale layer-specific structural constitutive model of the mitral heart valve leaflets.

    PubMed

    Zhang, Will; Ayoub, Salma; Liao, Jun; Sacks, Michael S

    2016-03-01

    Fundamental to developing a deeper understanding of pathophysiological remodeling in mitral valve (MV) disease is the development of an accurate tissue-level constitutive model. In the present work, we developed a novel meso-scale (i.e. at the level of the fiber, 10-100 μm in length scale) structural constitutive model (MSSCM) for MV leaflet tissues. Due to its four-layer structure, we focused on the contributions from the distinct collagen and elastin fiber networks within each tissue layer. Requisite collagen and elastin fibrous structural information for each layer were quantified using second harmonic generation microscopy and conventional histology. A comprehensive mechanical dataset was also used to guide model formulation and parameter estimation. Furthermore, novel to tissue-level structural constitutive modeling approaches, we allowed the collagen fiber recruitment function to vary with orientation. Results indicated that the MSSCM predicted a surprisingly consistent mean effective collagen fiber modulus of 162.72 MPa, and demonstrated excellent predictive capability for extra-physiological loading regimes. There were also anterior-posterior leaflet-specific differences, such as tighter collagen and elastin fiber orientation distributions (ODF) in the anterior leaflet, and a thicker and stiffer atrialis in the posterior leaflet. While a degree of angular variance was observed, the tight valvular tissue ODF also left little room for any physically meaningful angular variance in fiber mechanical responses. Finally, a novel fibril-level (0.1-1 μm) validation approach was used to compare the predicted collagen fiber/fibril mechanical behavior with extant MV small angle X-ray scattering data. Results demonstrated excellent agreement, indicating that the MSSCM fully captures the tissue-level function. Future utilization of the MSSCM in computational models of the MV will aid in producing highly accurate simulations in non-physiological loading states that can

  15. Congenital isolated cleft mitral valve leaflet and apical muscular ventricular septal defect in a Holstein calf.

    PubMed

    Depenbrock, Sarah M; Visser, Lance C; Kohnken, Rebecca A; Russell, Duncan S; Simpson, Katharine M; Bonagura, John D

    2015-09-01

    A 5-week-old Holstein heifer calf presented for emergency treatment of signs referable to gastrointestinal disease and hypovolemic shock. Fluid resuscitation uncovered clinical signs of primary cardiac disease and echocardiography revealed multiple congenital cardiac defects. Malformations included a cleft anterior mitral valve leaflet resembling an isolated cleft mitral valve and an apically-located muscular ventricular septal defect. The echocardiographic and postmortem findings associated with these defects are presented and discussed in this report.

  16. Tent-shape technique: another procedure to repair P2 of posterior leaflet of mitral valve.

    PubMed

    Kassem, Samer; Moasis, Ghassan A; Biglioli, Paolo

    2011-06-01

    In this report, we describe a new procedure to repair the prolapsing high mid-scallop of the mitral valve (MV) posterior leaflet (P2) with detailed consideration of the anatomy and physiology of the MV. A new artificial chord is implanted in the body of the P2 at the same height of non-prolapsing P1 and P3, and the remaining part of the prolapsing P2 is anchored to the artificial chord taking the shape of a tent.

  17. Ex vivo lung perfusion

    PubMed Central

    Machuca, Tiago N.

    2014-01-01

    Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs. PMID:25132972

  18. [Drug information for patients (Package Leaflets), and user testing in EU].

    PubMed

    Yamamoto, Michiko; Doi, Hirohisa; Furukawa, Aya

    2015-01-01

    Patients and consumers have desired high quality drug information in their pharmacotherapy, and are entitled to receive it. It is desirable that the information should be aimed at shared decision-making between patients and healthcare professionals about medications. The quality of drug information available to patients should also be assured. With an aim to improve the quality of "Drug Guide for Patients", we investigated Patient Information Leaflets (PILs) which are approved by the Medicines and Healthcare Products Regulatory Agency (MHRA) in the United Kingdom (UK) with regard to the criteria of development and user testing for assuring the quality of the PILs. In the European Union (EU), these are called Package Leaflets (PLs). PILs have been a legal requirement in the UK since 1999 for all medications. The user testing of PILs has been implemented as evidence since 2005 so that people can rely on the information provided in the leaflet. Execution of PILs which follow the guidance of the user testing, according to the guidance of this user testing, would reflect the views of patients. Here, we introduce the development process and implementation of user testing of PILs. In terms of readability, accessibility and understandability of drug information for patients, we need to discuss involving the public in decisions on how its quality should be assured and how it can be made easily be comprehensible for patients, in order to make effective use of "Drug Guide for Patients" in the future in Japan.

  19. Information leaflet as an adjunct to verbal counseling in obtaining informed consent.

    PubMed

    Gangol, R; Maharjan, D

    2010-01-01

    This study evaluates if addition of information leaflet after the usual verbal counseling improves the level of understanding of patients undergoing surgery about their disease, the need for surgery and its complications. It is a prospective observational case control study in which the control group receives verbal counseling only and the study group is given an information leaflet in addition to the verbal counseling after random allocation. An interviewer (surgical resident) interviews both the group using a set questionnaire. The answers are scored and added to give total marks. There were total 114 patients undergoing gall bladder surgery with 59 in the study group and 55 in the control group. The level of understanding was good or satisfactory in 18.2 % in the control group compared to 76.3% in the study group (P < 0.000). This statistically significant improvement was seen even among illiterate group when analyzed separately. Addition of information leaflet significantly improves the patients understanding of their disease irrespective of their education status.

  20. Nonlinear solid finite element analysis of mitral valves with heterogeneous leaflet layers

    NASA Astrophysics Data System (ADS)

    Prot, V.; Skallerud, B.

    2009-02-01

    An incompressible transversely isotropic hyperelastic material for solid finite element analysis of a porcine mitral valve response is described. The material model implementation is checked in single element tests and compared with a membrane implementation in an out-of-plane loading test to study how the layered structures modify the stress response for a simple geometry. Three different collagen layer arrangements are used in finite element analysis of the mitral valve. When the leaflets are arranged in two layers with the collagen on the ventricular side, the stress in the fibre direction through the thickness in the central part of the anterior leaflet is homogenized and the peak stress is reduced. A simulation using membrane elements is also carried out for comparison with the solid finite element results. Compared to echocardiographic measurements, the finite element models bulge too much in the left atrium. This may be due to evidence of active muscle fibres in some parts of the anterior leaflet, whereas our constitutive modelling is based on passive material.

  1. Papillary fibroelastoma of the anterior leaflet of the mitral valve mimicking vegetation

    PubMed Central

    Prifti, Edvin; Ikonomi, Majlinda; Veshti, Altin; Demiraj, Aurel; Xhaxho, Roland

    2015-01-01

    Introduction The papillary fibroelastoma (PFE) is a rare and benign primary cardiac tumor, and the mostly frequently found tumor occurring in cardiac valves. Case presentation We describe a 52 year old female presenting a history of 2 weeks of fever due to wound infection after breast’s surgery. A preoperative echocardiography demonstrated a mass >1 cm2 originating from the anterior leaflet of the mitral valve mimicking vegetation. The patient underwent successful surgical removal of the PFE. The histologic evaluation demonstrated a PFE. Discussion With the introduction of echocardiography, the diagnosis of these tumors in living patients has been reported sporadically. PFE have been found most often on valve leaflets, chordae tendineae, and both ventricles. The differential diagnosis of PFE includes other cardiac tumors, thrombus, vegetation, and Lambl’s excrescences. Conclusion To summarize, we report a PFE of the anterior leaflet of the mitral valve. The diagnosis was confirmed by histopathological examination after surgical removal. Finally, careful echocardiographic analyses during evaluation of valvular masses are strongly recommended for differential diagnosis. PMID:26209756

  2. Papillary fibroelastoma of the anterior leaflet of the mitral valve mimicking vegetation.

    PubMed

    Prifti, Edvin; Ikonomi, Majlinda; Veshti, Altin; Demiraj, Aurel; Xhaxho, Roland

    2015-01-01

    The papillary fibroelastoma (PFE) is a rare and benign primary cardiac tumor, and the mostly frequently found tumor occurring in cardiac valves. We describe a 52 year old female presenting a history of 2 weeks of fever due to wound infection after breast's surgery. A preoperative echocardiography demonstrated a mass >1cm(2) originating from the anterior leaflet of the mitral valve mimicking vegetation. The patient underwent successful surgical removal of the PFE. The histologic evaluation demonstrated a PFE. With the introduction of echocardiography, the diagnosis of these tumors in living patients has been reported sporadically. PFE have been found most often on valve leaflets, chordae tendineae, and both ventricles. The differential diagnosis of PFE includes other cardiac tumors, thrombus, vegetation, and Lambl's excrescences. To summarize, we report a PFE of the anterior leaflet of the mitral valve. The diagnosis was confirmed by histopathological examination after surgical removal. Finally, careful echocardiographic analyses during evaluation of valvular masses are strongly recommended for differential diagnosis. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Pointwise assessment of three-dimensional computer reconstruction of mitral leaflet surfaces from rotationally scanned echocardiograms in vitro.

    PubMed

    Bashein, Gerard; Legget, Malcolm E; Detmer, Paul R

    2004-03-01

    Three-dimensional transesophageal echocardiography offers promise for improved understanding of mitral leaflet pathology, but it has not been validated quantitatively, nor has the minimum number of imaging planes for satisfactory reconstruction been determined with a rotational scanning geometry. This study assessed its accuracy in vitro by comparing, on a 1 x 1-mm grid, the surfaces of mitral leaflets derived from 5-degree rotational ultrasonic scans with those derived from laser scans of casts of the atrial side of the leaflets. Overall, the ultrasonically derived surface had a mean absolute deviation of 0.65 +/- 0.12 mm from the laser-derived surface. Using only alternate imaging planes (10-degree increments) made no significant difference in the overall distribution of deviations (P =.56), although the distributions on some individual specimens differed markedly. We conclude that 5-degree rotational scanning in vitro can reconstruct the mitral valve leaflets with sufficient accuracy and detail to render clinically important features.

  4. Flush mounted hot film anemometer measurement of wall shear stress distal to a tri-leaflet valve for Newtonian and non-Newtonian blood analog fluids.

    PubMed

    Nandy, S; Tarbell, J M

    1987-01-01

    Wall shear stress has been measured by flush-mounted hot film anemometry distal to an Ionescu-Shiley tri-leaflet valve under pulsatile flow conditions. Both Newtonian (aqueous glycerol) and non-Newtonian (aqueous polyacrylamide) blood analog fluids were investigated. Significant differences in the axial distribution of wall shear stress between the two fluids are apparent in flows having nearly identical Reynolds numbers. The Newtonian fluid exhibits a (peak) wall shear rate which is maximized near the valve seat (30 mm) and then decays to a fully developed flow value (by 106 mm). In contrast, the shear rate of the non-Newtonian fluid at 30 mm is less than half that of the Newtonian fluid and at 106 mm is more than twice that of the Newtonian fluid. It is suggested that non-Newtonian rheology influences valve flow patterns either through alterations in valve opening associated with low shear separation zones behind valve leaflets, or because of variations in the rate of jet spreading. More detailed studies are required to clarify the mechanisms. The Newtonian wall shear stresses for this valve are low. The highest value observed anywhere in the aortic chamber was 2.85 N/m2 at a peak Reynolds number of 3694.

  5. Perfusion measurement in acute pancreatitis using dynamic perfusion MDCT.

    PubMed

    Bize, Pierre E; Platon, Alexandra; Becker, Christoph D; Poletti, Pierre-Alexandre

    2006-01-01

    Our objective was to determine whether MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis in the initial phase of the disease. One hundred six patients with abdominal pain were prospectively enrolled in this study. Patients were separated into two groups: P1 (severe) and P2 (mild) acute pancreatitis. Mean perfusion value was 24.8 mL/100 mL/min in the P1 group and 50.5 mL/100 mL/min in the P2 group (p = 0.0016, significant). Our preliminary data suggest that pancreatic perfusion measurement using MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis.

  6. Cerebral-Body Perfusion Model

    DTIC Science & Technology

    1990-07-01

    compared to the 0.5g curve) fall in flow. Fig. 9b, showing the 5g case, strongly suggests a possible, so-called, " luxury perfusion ", in which natural...as the luxury perfusion situation which bypasses the flow with the nutrients it carries (through newly opened collaterals) and result in a "blackout...89-0054 CEREBRAL-BODY PERFUSION MODEL S. Sorek’, J. Bear2, and M., Feinsod3 in Collaboration with K. Allen4, L. Bunt5 and S. Ben-IHaiM6 July 1990

  7. Advanced modeling strategy for the analysis of heart valve leaflet tissue mechanics using high-order finite element method.

    PubMed

    Mohammadi, Hadi; Bahramian, Fereshteh; Wan, Wankei

    2009-11-01

    Modeling soft tissue using the finite element method is one of the most challenging areas in the field of biomechanical engineering. To date, many models have been developed to describe heart valve leaflet tissue mechanics, which are accurate to some extent. Nevertheless, there is no comprehensive method to modeling soft tissue mechanics, This is because (1) the degree of anisotropy in the heart valve leaflet changes layer by layer due to a variety of collagen fiber densities and orientations that cannot be taken into account in the model and also (2) a constitutive material model fully describing the mechanical properties of the leaflet structure is not available in the literature. In this framework, we develop a new high-order element using p-type finite element formulation to create anisotropic material properties similar to those of the heart valve leaflet tissue in only one single element. This element also takes the nonlinearity of the leaflet tissue into consideration using a bilinear material model. This new element is composed a two-dimensional finite element in the principal directions of leaflet tissue and a p-type finite element in the direction of thickness. The proposed element is easy to implement, much more efficient than standard elements available in commercial finite element packages. This study is one step towards the modeling of soft tissue mechanics using a meshless finite element approach to be applied in real-time haptic feedback of soft-tissue models in virtual reality simulation.

  8. Time-dependent biaxial mechanical behavior of the aortic heart valve leaflet.

    PubMed

    Stella, John A; Liao, Jun; Sacks, Michael S

    2007-01-01

    Despite continued progress in the treatment of aortic valve (AV) disease, current treatments continue to be challenged to consistently restore AV function for extended durations. Improved approaches for AV repair and replacement rests upon our ability to more fully comprehend and simulate AV function. While the elastic behavior the AV leaflet (AVL) has been previously investigated, time-dependent behaviors under physiological biaxial loading states have yet to be quantified. In the current study, we performed strain rate, creep, and stress-relaxation experiments using porcine AVL under planar biaxial stretch and loaded to physiological levels (60 N/m equi-biaxial tension), with strain rates ranging from quasi-static to physiologic. The resulting stress-strain responses were found to be independent of strain rate, as was the observed low level of hysteresis ( approximately 17%). Stress relaxation and creep results indicated that while the AVL exhibited significant stress relaxation, it exhibited negligible creep over the 3h test duration. These results are all in accordance with our previous findings for the mitral valve anterior leaflet (MVAL) [Grashow, J.S., Sacks, M.S., Liao, J., Yoganathan, A.P., 2006a. Planar biaxial creep and stress relaxatin of the mitral valve anterior leaflet. Annals of Biomedical Engineering 34 (10), 1509-1518; Grashow, J.S., Yoganathan, A.P., Sacks, M.S., 2006b. Biaxial stress-stretch behavior of the mitral valve anterior leaflet at physiologic strain rates. Annals of Biomedical Engineering 34 (2), 315-325], and support our observations that valvular tissues are functionally anisotropic, quasi-elastic biological materials. These results appear to be unique to valvular tissues, and indicate an ability to withstand loading without time-dependent effects under physiologic loading conditions. Based on a recent study that suggested valvular collagen fibrils are not intrinsically viscoelastic [Liao, J., Yang, L., Grashow, J., Sacks, M.S., 2007

  9. Distributed Perfusion Educational Model: A Shift in Perfusion Economic Realities

    PubMed Central

    Austin, Jon W.; Evans, Edward L.; Hoerr, Harry R.

    2005-01-01

    Abstract: In recent years, a steady decline in the number of perfusion education programs in the United States has been noted. At the same time, there has been a parallel decline in the number of students graduated from perfusion educational programs in the United States. Also, as noted by several authors, there has been an increase in demand for perfusion graduates. The decline in programs and graduates has also been noted in anesthesia and surgical residency programs. The shift is caused by a combination of economic and clinical factors. First, decreased reimbursement has led to reallocation of hospital resources. Second, the original enthusiasm for beating heart coronary artery bypass surgery was grossly overestimated and has led to further reallocation of hospital resources and denigration of cardiopulmonary bypass. This paper describes two models of perfusion education programs: serial perfusion education model (SPEM) and the distributed perfusion education model (DPEM). Arguments are presented that the SPEM has some serious limitations and challenges for long-term economic survival. The authors feel the DPEM along with dependence on tuition funding can survive the current clinical and economic conditions and allow the profession to adapt to changes in scope of practice. PMID:16524152

  10. Pulmonary ventilation/perfusion scan

    MedlinePlus

    ... JavaScript. A pulmonary ventilation/perfusion scan involves two nuclear scan tests to measure breathing (ventilation) and circulation ( ... In: Mettler FA, Guiberteau MJ, eds. Essentials of Nuclear Medicine Imaging . 6th ed. Philadelphia, PA: Elsevier Saunders; ...

  11. Isolated heart perfusion according to Langendorff---still viable in the new millennium.

    PubMed

    Skrzypiec-Spring, Monika; Grotthus, Bartosz; Szelag, Adam; Schulz, Richard

    2007-01-01

    The isolated perfused mammalian heart preparation was established in 1897 by Oscar Langendorff. The method was developed on the basis of the isolated perfused frog heart established by Elias Cyon at the Carl Ludwig Institute of Physiology in Leipzig, Germany in 1866. Observations made using both methods at the end of the 19th and at the beginning of the 20th century led to important discoveries, forming the basis for our understanding of heart physiology. This included the role of temperature, oxygen and calcium ions for heart contractile function, the origin of cardiac electrical activity in the atrium, the negative chronotropic effect of vagus stimulation and the chemical transmission of impulses in the vagus nerve by acetylcholine. Langendorff himself demonstrated that the heart receives its nutrients and oxygen from blood via the coronary arteries and that cardiac mechanical function is reflected by changes in the coronary circulation. The method underwent many modifications but its general principle remains the same today. Blood, or more commonly crystalloid perfusates, are delivered into the heart through a cannula inserted in the ascending aorta, either at constant pressure or constant flow. Retrograde flow in the aorta closes the leaflets of the aortic valve and as a consequence, the entire perfusate enters the coronary arteries via the ostia at the aortic root. After passing through the coronary circulation the perfusate drains into the right atrium via the coronary sinus. The simplicity of the isolated mammalian heart preparation, the broad spectrum of measurements which can be done using this method, its high reproducibility and relatively low cost make it a very useful tool in modern cardiovascular and pharmacological research, in spite of a few shortcomings. In the last decade the method has brought many important advances in many areas including ischemia-reperfusion injury, cell-based therapy and donor heart preservation for transplant.

  12. Non-ischemic perfusion defects due to delayed arrival of contrast material on stress perfusion cardiac magnetic resonance imaging after coronary artery bypass graft surgery.

    PubMed

    Kim, Yeo Koon; Park, Eun-Ah; Park, Sang Joon; Cheon, Gi Jeong; Lee, Whal; Chung, Jin Wook; Park, Jae Hyung

    2014-01-01

    Herein we report about the adenosine stress perfusion MR imaging findings of a 50-year-old man who exhibited two different perfusion defects resulting from two different mechanisms after a coronary artery bypass surgery. An invasive coronary angiography confirmed that one perfusion defect at the mid-anterior wall resulted from an ischemia due to graft stenosis. However, no stenosis was detected on the graft responsible for the mid-inferior wall showing the other perfusion defect. It was assumed that the perfusion defect at the mid-inferior wall resulted from delayed perfusion owing to the long pathway of the bypass graft. The semiquantitative analysis of corrected signal-time curves supported our speculation, demonstrating that the rest-to-stress ratio index of the maximal slope of the myocardial territory in question was similar to those of normal myocardium, whereas that of myocardium with the stenotic graft showed a typical ischemic pattern. A delayed perfusion during long graft pathway in a post-bypass graft patient can mimick a true perfusion defect on myocardial stress MR imaging. Radiologists should be aware of this knowledge to avoid misinterpretation of graft and myocardial status in post bypass surgery patients.

  13. Myocardial perfusion during exercise in endurance-trained and untrained humans.

    PubMed

    Laaksonen, Marko S; Kalliokoski, Kari K; Luotolahti, Matti; Kemppainen, Jukka; Teräs, Mika; Kyröläinen, Heikki; Nuutila, Pirjo; Knuuti, Juhani

    2007-08-01

    Because of technical challenges very little is known about absolute myocardial perfusion in humans in vivo during physical exercise. In the present study we applied positron emission tomography (PET) in order to 1) investigate the effects of dynamic bicycle exercise on myocardial perfusion and 2) clarify the possible effects of endurance training on myocardial perfusion during exercise. Myocardial perfusion was measured in endurance-trained and healthy untrained subjects at rest and during absolutely the same (150 W) and relatively similar [70% maximal power output (W(max))] bicycle exercise intensities. On average, the absolute myocardial perfusion was 3.4-fold higher during 150 W (P < 0.001) and 4.9-fold higher during 70% W(max) (P < 0.001) than at rest. At 150 W myocardial perfusion was 46% lower in endurance-trained than in untrained subjects (1.67 +/- 0.45 vs. 3.00 +/- 0.75 ml x g(-1) x min(-1); P < 0.05), whereas during 70% W(max) perfusion was not significantly different between groups (P = not significant). When myocardial perfusion was normalized with rate-pressure product, the results were similar. Thus, according to the present results, myocardial perfusion increases in parallel with the increase in working intensity and in myocardial work rate. Endurance training seems to affect myocardial blood flow pattern during submaximal exercise and leads to more efficient myocardial pump function.

  14. Nifedipine increases fetoplacental perfusion.

    PubMed

    Karahanoglu, Ertugrul; Altinboga, Orhan; Akpinar, Funda; Demirdag, Erhan; Ozdemirci, Safak; Akyol, Aysegul; Yalvac, Serdar

    2017-01-01

    Our aim is to evaluate the effect of nifedipine on fetoplacental hemodynamic parameters. A retrospective study was conducted at a tertiary center with 30 patients for whom nifedipine treatment was used as a tocolytic therapy for preterm labor. Initiation of this treatment was at 31.6±2.5 weeks of gestation. We combined the pulse Doppler imaging parameters with grayscale imaging via the Bernoulli theorem, which is called the "continuity equation", to get the fetoplacental perfusion (FPP). Evaluated parameters were the resistance index (RI), the pulsatility index (PI), systole/diastole ratios (S/D), the velocity-time integral of the umbilical artery (VTI), the radius of the umbilical artery, the peak systolic velocity and the mean pressure gradient in the umbilical artery. From these parameters, the FPP was acquired. We found that the RI, the PI and the S/D ratio did not change after treatment with nifedipine. The mean pressure gradient, the VTI and the peak systolic velocity increased after treatment with nifedipine. Nifedipine increases FPP from 166±73.81 beat.cm3/min to 220±83.3 beat.cm3/min. Although nifedipine had no effect on the PI, the RI or the S/D, it increased the mean pressure gradient, the VTI and FPP.

  15. CAD of myocardial perfusion

    NASA Astrophysics Data System (ADS)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2007-03-01

    Our purpose is in the automated evaluation of the physiological relevance of lesions in coronary angiograms. We aim to extract as much as possible quantitative information about the physiological condition of the heart from standard angiographic image sequences. Coronary angiography is still the gold standard for evaluating and diagnosing coronary abnormalities as it is able to locate precisely the coronary artery lesions. The dimensions of the stenosis can be assessed nowadays successfully with image processing based Quantitative Coronary Angiography (QCA) techniques. Our purpose is to assess the clinical relevance of the pertinent stenosis. We therefore analyze the myocardial perfusion as revealed in standard angiographic image sequences. In a Region-of-Interest (ROI) on the angiogram (without an overlaying major blood vessel) the contrast is measured as a function of time (the so-called time-density curve). The required hyperemic state of exercise is induced artificially by the injection of a vasodilator drug e.g. papaverine. In order to minimize motion artifacts we select based on the recorded ECG signal end-diastolic images in both a basal and a hyperemic run in the same projection to position the ROI. We present the development of the algorithms together with results of a small study of 20 patients which have been catheterized following the standard protocol.

  16. Regional pulmonary perfusion following human heart-lung transplantation

    SciTech Connect

    Lisbona, R.; Hakim, T.S.; Dean, G.W.; Langleben, D.; Guerraty, A.; Levy, R.D. )

    1989-08-01

    Ventilation and perfusion scans were obtained in six subjects who had undergone heart-lung transplantation with consequent denervation of the cardiopulmonary axis. Two of the subjects had developed obliterative bronchiolitis, which is believed to be a form of chronic rejection. Their pulmonary function tests demonstrated airflow obstruction and their scintigraphic studies were abnormal. In the remaining four subjects without obstructive airways disease, ventilation and planar perfusion scans were normal. Single photon emission computed tomography imaging of pulmonary perfusion in these patients revealed a layered distribution of blood flow indistinguishable from that of normal individuals. It is concluded that neurogenic mechanisms have little influence on the pattern of local pulmonary blood flow at rest.

  17. Quantitative variations of individual carotenoids in relationship with the leaflet development of six species of the genus Ceratozamia (Cycads).

    PubMed

    Cardini, Franco; Pucci, Susanna; Calamassi, Roberto

    2006-02-01

    The content and relative variations of individual carotenoids during the leaflet development stages (I, II, III, A and P) of six species of Ceratozamia (Cycads) were investigated. There is an unusual, transitory and marked presence of six red stroma keto-carotenoids in the first development stages, while the thylakoidal carotenoids showed a low concentration during the same period. As no official A1cm1% coefficients were available, it was necessary to calculate these for the following stroma carotenoids: semi-beta-carotenone (major component), triphasiaxanthin, ceratoxanthin, ceratozamiaxanthin, kuesteriaxanthin and ceratoxanthone. The stroma keto-carotenoids, which reached the highest content in the first development stage (average of 78% of total carotenoids), were always present in the five species: C. fuscoviridis, C. robusta, C. spinosa, C. kuesteriana and C. hildae, but never in C. mexicana. From stage II, the stroma keto-carotenoids decreased and finally disappeared in the green adult leaflets. The thylakoidal carotenoids showed a minimum at stage III, and then increased to a maximum in the perennial leaflets. Among these, beta-carotene showed an anomalous and characteristic behaviour, being a minor component during leaflet development (from stage I to A). In stage P it was markedly exceeded not only by lutein but also by alpha-carotene, neoxanthin and violaxanthin, and in C. robusta also by lutein-5,6-epoxide. Additionally, the alpha/beta ratio in these species is unusual: it increased from 0.3-0.5 to 1.5-3.0 during leaflet development. Moreover, antheraxanthin amounts are very small, while zeaxanthin was present only in the evergreen leaflets of C. mexicana in small quantities. Lutein-5,6-epoxide represented more than 5% of thylakoidal carotenoids in the leaflets of all the species. A revision of the taxonomic rank of C. fuscoviridis is recommended.

  18. Participants' preference for type of leaflet used to feed back the results of a randomised trial: a survey.

    PubMed

    Brealey, Stephen; Andronis, Lazaros; Dennis, Laura; Atwell, Christine; Bryan, Stirling; Coulton, Simon; Cox, Helen; Cross, Ben; Fylan, Fiona; Garratt, Andrew; Gilbert, Fiona; Gillan, Maureen; Hendry, Maggie; Hood, Kerenza; Houston, Helen; King, David; Morton, Veronica; Robling, Michael; Russell, Ian; Wilkinson, Clare

    2010-12-01

    Hundreds of thousands of volunteers take part in medical research, but many will never hear from researchers about what the study revealed. There is a growing demand for the results of randomised trials to be fed back to research participants both for ethical research practice and for ensuring their co-operation in a trial. This study aims to determine participants' preferences for type of leaflet (short versus long) used to summarise the findings of a randomised trial; and to test whether certain characteristics explained participants' preferences. 553 participants in a randomised trial about General Practitioners' access to Magnetic Resonance Imaging for patients presenting with suspected internal derangement of the knee were asked in the final follow-up questionnaire whether they would like to be fed back the results of the trial. Participants who agreed to this were included in a postal questionnaire survey asking about their preference, if any, between a short and a long leaflet and what it was about the leaflet that they preferred. Multinomial logistic regression was used to test whether certain demographics of responding participants along with treatment group explained whether a participant had a preference for type of leaflet or no preference. Of the participants who returned the final follow-up questionnaire, 416 (88%) agreed to receive the results of the trial. Subsequently 132 (32%) participants responded to the survey. Most participants preferred the longer leaflet (55%) and the main reasons for this were the use of technical information (94%) and diagrams (89%). There was weak evidence to suggest that gender might explain whether participants have a preference for type of leaflet or not (P = 0.084). Trial participants want to receive feed back about the results and appear to prefer a longer leaflet. Males and females might require information to be communicated to them differently and should be the focus of further research. The trial is registered

  19. Low literacy and written drug information: information-seeking, leaflet evaluation and preferences, and roles for images.

    PubMed

    van Beusekom, Mara M; Grootens-Wiegers, Petronella; Bos, Mark J W; Guchelaar, Henk-Jan; van den Broek, Jos M

    2016-12-01

    Background Low-literate patients are at risk to misinterpret written drug information. For the (co-) design of targeted patient information, it is key to involve this group in determining their communication barriers and information needs. Objective To gain insight into how people with low literacy use and evaluate written drug information, and to identify ways in which they feel the patient leaflet can be improved, and in particular how images could be used. Setting Food banks and an education institution for Dutch language training in the Netherlands. Method Semi-structured focus groups and individual interviews were held with low-literate participants (n = 45). The thematic framework approach was used for analysis to identify themes in the data. Main outcome measure Low-literate people's experience with patient information leaflets, ideas for improvements, and perceptions on possible uses for visuals. Results Patient information leaflets were considered discouraging to use, and information difficult to find and understand. Many rely on alternative information sources. The leaflet should be shorter, and improved in terms of organisation, legibility and readability. Participants thought images could increase the leaflet's appeal, help ask questions, provide an overview, help understand textual information, aid recall, reassure, and even lead to increased confidence, empowerment and feeling of safety. Conclusion Already at the stages of paying attention to the leaflet and maintaining interest in the message, low-literate patients experience barriers in the communication process through written drug information. Short, structured, visual/textual explanations can lower the motivational threshold to use the leaflet, improve understanding, and empower the low-literate target group.

  20. The adverse effects of reduced cerebral perfusion on cognition and brain structure in older adults with cardiovascular disease

    PubMed Central

    Alosco, Michael L; Gunstad, John; Jerskey, Beth A; Xu, Xiaomeng; Clark, Uraina S; Hassenstab, Jason; Cote, Denise M; Walsh, Edward G; Labbe, Donald R; Hoge, Richard; Cohen, Ronald A; Sweet, Lawrence H

    2013-01-01

    Background It is well established that aging and vascular processes interact to disrupt cerebral hemodynamics in older adults. However, the independent effects of cerebral perfusion on neurocognitive function among older adults remain poorly understood. We examined the associations among cerebral perfusion, cognitive function, and brain structure in older adults with varying degrees of vascular disease using perfusion magnetic resonance imaging (MRI) arterial spin labeling (ASL). Materials and methods 52 older adults underwent neuroimaging and were administered the Mini Mental State Examination (MMSE), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and measures of attention/executive function. ASL and T1-weighted MRI were used to quantify total brain perfusion, total brain volume (TBV), and cortical thickness. Results Regression analyses showed reduced total brain perfusion was associated with poorer performance on the MMSE, RBANS total index, immediate and delayed memory composites, and Trail Making Test B. Reduced frontal lobe perfusion was associated with worse executive and memory function. A similar pattern emerged between temporal lobe perfusion and immediate memory. Regression analyses revealed that decreased total brain perfusion was associated with smaller TBV and mean cortical thickness. Regional effects of reduced total cerebral perfusion were found on temporal and parietal lobe volumes and frontal and temporal cortical thickness. Discussion Reduced cerebral perfusion is independently associated with poorer cognition, smaller TBV, and reduced cortical thickness in older adults. Conclusion Prospective studies are needed to clarify patterns of cognitive decline and brain atrophy associated with cerebral hypoperfusion. PMID:24363966

  1. Effects of acute ischemic mitral regurgitation on three-dimensional mitral leaflet edge geometry.

    PubMed

    Bothe, Wolfgang; Nguyen, Tom C; Ennis, Daniel B; Itoh, Akinobu; Carlhäll, Carl Johan; Lai, David T; Ingels, Neil B; Miller, D Craig

    2008-02-01

    Improved quantitative understanding of in vivo leaflet geometry in ischemic mitral regurgitation (IMR) is needed to improve reparative techniques, yet few data are available due to current imaging limitations. Using marker technology we tested the hypotheses that IMR (1) occurs chiefly during early systole; (2) affects primarily the valve region contiguous with the myocardial ischemic insult; and (3) results in systolic leaflet edge restriction. Eleven sheep had radiopaque markers sutured as five opposing pairs along the anterior (A(1)-E(1)) and posterior (A(2)-E(2)) mitral leaflet free edges from the anterior commissure (A(1)-A(2)) to the posterior commissure (E(1)-E(2)). Immediately postoperatively, biplane videofluoroscopy was used to obtain 4D marker coordinates before and during acute proximal left circumflex artery occlusion. Regional mitral orifice area (MOA) was calculated in the anterior (Ant-MOA), middle (Mid-MOA), and posterior (Post-MOA) mitral orifice segments during early systole (EarlyS), mid systole (MidS), and end systole (EndS). MOA was normalized to zero (minimum orifice opening) at baseline EndS. Tenting height was the distance of the midpoint of paired markers to the mitral annular plane at EndS. Acute ischemia increased echocardiographic MR grade (0.5+/-0.3 vs 2.3+/-0.7, p<0.01) and MOA in all regions at EarlyS, MidS, and EndS: Ant-MOA (7+/-10 vs 22+/-19 mm(2), 1+/-2 vs 18+/-16 mm(2), 0 vs 17+/-15 mm(2)); Mid-MOA (9+/-13 vs 25+/-17 mm(2), 3+/-6 vs 21+/-19 mm(2), 0 vs 25+/-17 mm(2)); and Post-MOA (8+/-10 vs 25+/-16, 2+/-4 vs 22+/-13 mm(2), 0 vs 23+/-13 mm(2)), all p<0.05. There was no change in MOA throughout systole (EarlyS vs MidS vs EndS) during baseline conditions or ischemia. Tenting height increased with ischemia near the central and the anterior commissure leaflet edges (B(1)-B(2): 7.1+/-1.8mm vs 7.9+/-1.7 mm, C(1)-C(2): 6.9+/-1.3mm vs 8.0+/-1.5mm, both p<0.05). MOA during ischemia was larger throughout systole, indicating that acute IMR

  2. EFFECTS OF ACUTE ISCHEMIC MITRAL REGURGITATION ON THREE DIMENSIONAL MITRAL LEAFLET EDGE GEOMETRY

    PubMed Central

    Bothe, Wolfgang; Nguyen, Tom C.; Ennis, Daniel B.; Itoh, Akinobu; Carlhäll, Carl Johan; Lai, David T.; Ingels, Neil B.; Miller, D. Craig

    2008-01-01

    Background: Improved quantitative understanding of in-vivo leaflet geometry in ischemic mitral regurgitation (IMR) is needed to improve reparative techniques, yet few data are available due to current imaging limitations. Using marker technology we tested the hypotheses that IMR: (1) Occurs chiefly during early-systole; (2) Affects primarily the valve region contiguous with the myocardial ischemic insult; and, (3) Results in systolic leaflet edge restriction. Methods: Eleven sheep had radiopaque markers sutured as five opposing pairs along the anterior (A1-E1) and posterior (A2-E2) mitral leaflet free-edges from the anterior commissure (A1-A2) to the posterior commissure (E1-E2). Immediately postoperatively, biplane videofluoroscopy was used to obtain 4-D marker coordinates before and during acute proximal left circumflex artery occlusion. Regional mitral orifice area (MOA) was calculated in the anterior (Ant-MOA), middle (Mid-MOA) and posterior (Post-MOA) mitral orifice segments during early-systole (EarlyS), mid-systole (MidS), and end-systole (EndS). MOA was normalized to zero (minimum orifice opening) at baseline EndS. Tenting height was the distance of the midpoint of paired markers to the mitral annular plane at EndS. . Results: Acute ischemia increased echocardiographic MR grade (0.5±0.3 vs. 2.3±0.7, p<0.01) and MOA in all regions at EarlyS, MidS and EndS: Ant-MOA (7±10 vs. 22±19mm2, 1±2 vs. 18±16mm2, 0 vs. 17±15mm2); Mid-MOA (9±13 vs. 25±17mm2, 3±6 vs. 21±19mm2, 0 vs. 25±17mm2); and Post-MOA (8±10 vs. 25±16, 2±4 vs. 22±13mm2, 0 vs. 23±13mm2), all p<0.05. There was no change in MOA throughout systole (EarlyS vs. MidS vs. EndS) during baseline conditions or ischemia. Tenting height increased with ischemia near the central and the anterior commissure leaflet edges (B1-B2: 7.1±1.8mm vs. 7.9±1.7mm, C1-C2: 6.9±1.3mm vs. 8.0±1.5mm, both p<0.05). Conclusions: (1) MOA during ischemia was larger throughout systole, indicating that acute IMR in

  3. BOLD-Perfusion Coupling during Monocular and Binocular Stimulation

    PubMed Central

    Gauthier, Claudine; Hoge, Richard D.

    2008-01-01

    Previous studies have suggested that during selective activation of a subset of the zones comprising a columnar system in visual cortex, perfusion increases uniformly in all columns of the system, while increases in oxidative metabolism occur predominantly in the activated columns. This could lead to disproportionately large blood oxygenation level-dependent (BOLD) signal increases for a given flow increase during monocular (relative to binocular) stimulation, due to contributions from columns which undergo large increases in perfusion with little or no change in oxidative metabolism. In the present study, we sought to test this hypothesis by measuring BOLD-perfusion coupling ratios in spatially averaged signals over V1 during monocular and binocular visual stimulation. It was found that, although withholding input to one eye resulted in statistically significant decreases in BOLD and perfusion signals in primary visual cortex, the ratio between BOLD and perfusion increases did not change significantly. These results do not support a gross mismatch between spatial patterns of flow and metabolism response during monocular stimulation. PMID:18350120

  4. Evaluation of Australian dermatological postoperative patient information leaflets: Should we have a national checklist?

    PubMed

    Hunt, William Tn; O'Sullivan, Niamh-Anna; Donnelly, Alan

    2017-04-20

    Patient information leaflets (PILs) are frequently provided to patients following dermatological surgery to provide advice and reassurance in the community. This evaluation reviewed the guidance specified in postoperative PILs across the 40 Australian dermatology teaching departments and clinics. All 40 departments and clinics were identified and asked to provide their postoperative information leaflets on sutured wound care (preferable) or excision biopsy (September-October 2015). For each PIL, 10 preselected parameters were evaluated. In total, 28/40 (70%) of units responded. From these units, 11/28 (39.3%) stated they do not use a postoperative PIL. Of the 17 units that provided PILs, the mode minimum dressing duration was 24 (6/17; 35.3%) and 48 h (6/17; 35.3%). For haemostatic advice, 12 PILs specified the time to press on a bleeding wound, with the most common advice being 10 (3/12; 25%) and 20 min (3/12; 25%). Of the 14 PILs that provided analgesic advice, the mode information suggested using paracetamol only and avoiding aspirin (4/14, 28.6%). Two or more signs of infection were stated in 11/17 (64.7%) PILs; 7/17 (41.2%) advised applying petroleum jelly to the wound, almost all PILs highlighted the contact for postoperative problems 16/17 (94.1%), and 5/17 (29.4%) leaflets mentioned scarring. Altogether 8/17 (47.1%) of PILs advised on the timeframe until active exercise could resume postoperatively. Guidance provided in Australian postoperative dermatological PILs is heterogeneous. A consensus checklist or template would be beneficial and ensure that advice provided to patients is more consistent; this could be adapted for local factors. © 2017 The Australasian College of Dermatologists.

  5. Influence of aortic valve leaflet calcification on dynamic aortic valve motion assessed by cardiac computed tomography.

    PubMed

    Minami, Keisuke; Yoneyama, Kihei; Izumo, Masaki; Suzuki, Kengo; Ogawa, Yasuyoshi; Chikaraishi, Kousuke; Ogawa, Yukihisa; Kobayashi, Yasuyuki; Furukawa, Toshiyuki; Tanabe, Yasuhiro; Akashi, Yoshihiro J

    Computed tomography is the best noninvasive imaging modality for evaluating valve leaflet calcification. To evaluate the association of aortic valve leaflet calcification with instantaneous valve opening and closing using dynamic multidetector computed tomography (MDCT). We retrospectively evaluated 58 consecutive patients who underwent dynamic MDCT imaging. Aortic valve calcification (AVC) was quantified using the Agatston method. The aortic valve area (AVA) tracking curves were derived by planimetry during the cardiac cycle using all 20 phases (5% reconstruction). da/dt in cm(2)/s was calculated as the rate of change of AVA during opening (positive) or closing (negative). Patients were divided into 3 three groups according to Agatston score quartile: no AVC (Q2, Score 0, n = 18), mild AVC (Q3, Score 1-2254, n = 24), and severe AVC (Q4 Score >2254, n = 14). In multivariable linear regression, compared to the non AVC group, the mild and severe AVC groups had lower maximum AVA (by -1.71 cm(2) and -2.25 cm(2), respectively), lower peak positive da/dt (by -21.88 cm(2)/s and -26.65 cm(2)/s, respectively), and higher peak negative da/dt (by 13.78 cm(2)/s and 18.11 cm(2)/s, respectively) (p < 0.05 for all comparisons). AVA and its opening and closing were influenced by leaflet calcification. The present study demonstrates the ability of dynamic MDCT imaging to assess quantitative aortic valve motion in a clinical setting. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  6. [Leaflets and websites on colorectal cancer screening and their quality assessment from experts' views].

    PubMed

    Dreier, M; Borutta, B; Seidel, G; Münch, I; Töppich, J; Bitzer, E-M; Dierks, M-L; Walter, U

    2014-03-01

    In Germany, individuals who have statutory health insurance have free access to colorectal cancer (CRC) screening tests, and can choose between a fecal occult blood test and a screening colonoscopy. Evidence-based health information may support informed choices regarding whether or not to undergo CRC screening. The aim of this study was to assess whether the available German information materials on CRC screening meet evidence-based health information standards. A systematic search was made for print media and websites on CRC screening addressed to German people with average CRC risk (search period for print media August 2010, for websites January-March 2012). The identified information was assessed with a newly developed comprehensive list of criteria. In all, 41 print media, including 28 flyers and 13 brochures, and 36 websites were identified and assessed. These materials reported more often the benefits than the risks of CRC screening, and quantified presentations of benefits and risks were less frequently given. Most of the materials called for participation and did not indicate the option to decide whether or not to attend CRC screening. This bias in favor of screening was increased by fear-provoking or downplayed wording. Most materials included false and misleading information. The requirements for evidence-based patient information were currently not met by most of the leaflets and websites in Germany. Feedback was given to the producers of the leaflets including a discussion of the findings. The results may be used to revise existing leaflets or to develop new health information on CRC screening.

  7. Nonresectional Single-Suture Leaflet Remodeling for Degenerative Mitral Regurgitation Facilitates Minimally Invasive Mitral Valve Repair

    PubMed Central

    MacArthur, John W.; Cohen, Jeffrey E.; Goldstone, Andrew B.; Fairman, Alexander S.; Edwards, Bryan B.; Hornick, Matthew A.; Atluri, Pavan; Woo, Y. Joseph

    2014-01-01

    Background Both leaflet resection and neochordal construction are effective mitral repair techniques, but they may become incrementally time-consuming when using minimally invasive approaches. We have used a single-suture leaflet-remodeling technique of inverting the prolapsed or flail segment tissue into the left ventricle. This repair is straightforward, expeditious, and facilitates a minimally invasive approach. Methods Ninety-nine patients with degenerative mitral regurgitation (MR) underwent a minimally invasive single-suture repair of the mitral valve from May 2007 through December 2012. Preoperative and perioperative echocardiograms as well as patient outcomes were analyzed and compared with those obtained from patients undergoing minimally invasive mitral valve repair using quadrangular resection at the same institution during the same period. Results All 99 patients had a successful mitral repair through a sternal-sparing minimally invasive approach. Ninety-one of the 99 patients had zero MR on postoperative echocardiogram, and 8 of 99 had trace to mild MR. Patients in the nonresectional group had significantly shorter cardiopulmonary bypass and cross-clamp times compared with the quadrangular resection group (115.8 ± 41.7 minutes versus 144.9 ± 38.2 minutes; p < 0.001; 76.2 ± 28.1 minutes versus 112.6 ± 33.5 minutes; p < 0.001, respectively). The mean length of stay was 7.5 ± 3 days. All patients were discharged alive and free from clinical symptoms of MR. There have been no reoperations for recurrent MR on subsequent average follow-up of 1 year. Conclusions An effective, highly efficient, and thus far durable single-suture mitral leaflet-remodeling technique facilitates minimally invasive repair of degenerative MR. PMID:23932318

  8. Stress-strain behavior of mitral valve leaflets in the beating ovine heart.

    PubMed

    Krishnamurthy, Gaurav; Itoh, Akinobu; Bothe, Wolfgang; Swanson, Julia C; Kuhl, Ellen; Karlsson, Matts; Craig Miller, D; Ingels, Neil B

    2009-08-25

    Excised anterior mitral leaflets exhibit anisotropic, non-linear material behavior with pre-transitional stiffness ranging from 0.06 to 0.09 N/mm(2) and post-transitional stiffness from 2 to 9 N/mm(2). We used inverse finite element (FE) analysis to test, for the first time, whether the anterior mitral leaflet (AML), in vivo, exhibits similar non-linear behavior during isovolumic relaxation (IVR). Miniature radiopaque markers were sewn to the mitral annulus, AML, and papillary muscles in 8 sheep. Four-dimensional marker coordinates were obtained using biplane videofluoroscopic imaging during three consecutive cardiac cycles. A FE model of the AML was developed using marker coordinates at the end of isovolumic relaxation (when pressure difference across the valve is approximately zero), as the reference state. AML displacements were simulated during IVR using measured left ventricular and atrial pressures. AML elastic moduli in the radial and circumferential directions were obtained for each heartbeat by inverse FEA, minimizing the difference between simulated and measured displacements. Stress-strain curves for each beat were obtained from the FE model at incrementally increasing transmitral pressure intervals during IVR. Linear regression of 24 individual stress-strain curves (8 hearts, 3 beats each) yielded a mean (+/-SD) linear correlation coefficient (r(2)) of 0.994+/-0.003 for the circumferential direction and 0.995+/-0.003 for the radial direction. Thus, unlike isolated leaflets, the AML, in vivo, operates linearly over a physiologic range of pressures in the closed mitral valve.

  9. Stress-Strain Behavior of Mitral Valve Leaflets in the Beating Ovine Heart

    PubMed Central

    Krishnamurthy, Gaurav; Itoh, Akinobu; Bothe, Wolfgang; Swanson, Julia C.; Kuhl, Ellen; Karlsson, Matts; Miller, D. Craig; Ingels, Neil B.

    2009-01-01

    Excised anterior mitral leaflets exhibit anisotropic, nonlinear material behavior with pre-transitional stiffness ranging from 0.06-0.09 N/mm2 and post-transitional stiffness from 2-9 N/mm2. We used inverse finite element (FE) analysis to test, for the first time, whether the anterior mitral leaflet (AML), in vivo, exhibits similar non-linear behavior during isovolumic relaxation (IVR). Miniature radiopaque markers were sewn to the mitral annulus, AML, and papillary muscles in 8 sheep. 4-D marker coordinates were obtained using biplane videofluoroscopic imaging during three consecutive cardiac cycles. A FE model of the AML was developed using marker coordinates at the end of isovolumic relaxation (when pressure difference across the valve is approximately zero), as the reference state. AML displacements were simulated during IVR using measured left ventricular and atrial pressures. AML elastic moduli in the radial and circumferential directions were obtained for each heartbeat by inverse FEA, minimizing the difference between simulated and measured displacements. Stress-strain curves for each beat were obtained from the FE model at incrementally-increasing transmitral pressure intervals during IVR. Linear regression of 24 individual stress-strain curves (8 hearts, 3 beats each) yielded a mean (±SD) linear correlation coefficient (r2) of 0.994±0.003 for the circumferential direction and 0.995±0.003 for the radial direction. Thus, unlike isolated leaflets, the AML, in vivo, operates linearly over a physiologic range of pressures in the closed mitral valve. PMID:19535081

  10. Usefulness of an educational leaflet to modify sexual risk behaviour in women with external genital warts.

    PubMed

    Cortes-Bordoy, Javier; Vidart, José A; Coll-Capdevila, Carme; Colombo, José A; Ramírez, Patricia

    2010-01-01

    We aimed to assess the effectiveness of an educational leaflet to modify sexual risk behaviour in women with external genital warts. Women with genital warts who attended in daily gynecological practice participated in a 12-month prospective randomised observational study. Randomisation was carried out by centres. At the initial visit, patients underwent complete gynecological examination, including an acetic acid test. Those assigned to the intervention group received an educational leaflet to improve patient's knowledge about warts (counselled group). Only patients with complete clearance after 6 months of initial therapy continued the study. The counselled group included 114 women and the non-counselled group 97. A significant increase in the use of condoms at visit 3 as compared with baseline (83.2% vs 66.1%, P < 0.05) was observed in the counselled group. The mean number of sexual partners was also significantly lower in the counselled group at each follow-up visit. Recurrences were documented in 9 of the 145 patients who completed the study (recurrence rate 6.2%). Recurrences occurred in 7 patients in the counselled group and in 2 in the non-counselled group (8.6% vs 3.1%, P = 0.299), and in all cases occurred at 9 months after initiation of treatment. In conclusion, the educational leaflet, which is simple and easy to implement in routine daily practice, proved to be effective in modifying sexual risk behaviour in women with external genital warts. This educational strategy did not seem to affect recurrence if an acetic acid test is routinely performed during the initial work-up studies.

  11. Introduction of a paediatric anaesthesia comic information leaflet reduced preoperative anxiety in children

    PubMed Central

    Kassai, B.; Rabilloud, M.; Dantony, E.; Grousson, S.; Revol, O.; Malik, S.; Ginhoux, T.; Touil, N.; Chassard, D.; Pereira de Souza Neto, E.

    2016-01-01

    Background The aim of the study was to determine whether the introduction of a paediatric anaesthesia comic information leaflet reduced preoperative anxiety levels of children undergoing major surgery. Secondary objectives were to determine whether the level of understanding of participants and other risk factors influence STAIC-S (State–Trait Anxiety Inventory for Children—State subscale) score in children. Methods We performed a randomized controlled parallel-group trial comparing preoperative anxiety between two groups of children aged >6 and <17 yr. Before surgery, the intervention group received a comic information leaflet at home in addition to routine information given by the anaesthetist at least 1 day before surgery. The control group received the routine information only. The outcome measure was the difference between STAIC-S scores measured before any intervention and after the anaesthetist's visit. A multiple regression analysis was performed to explore the influence of the level of education, the anxiety of parents, and the childrens' intelligence quotient on STAIC-S scores. Results One hundred and fifteen children were randomized between April 2009 and April 2013. An intention-to-treat analysis on data from 111 patients showed a significant reduction (P=0.002) in STAIC-S in the intervention group (n=54, mean=−2.2) compared with the control group (n=57, mean=0.90). The multiple regression analysis did not show any influence on STAIC-S scores of the level of education, parental anxiety, or the intelligence quotient of the children. Conclusions A paediatric anaesthesia comic information leaflet was a cheap and effective means of reducing preoperative anxiety, measured by STAIC-S, in children. Clinical trials registration NCT 00841022. PMID:27317708

  12. Introduction of a paediatric anaesthesia comic information leaflet reduced preoperative anxiety in children.

    PubMed

    Kassai, B; Rabilloud, M; Dantony, E; Grousson, S; Revol, O; Malik, S; Ginhoux, T; Touil, N; Chassard, D; Pereira de Souza Neto, E

    2016-07-01

    The aim of the study was to determine whether the introduction of a paediatric anaesthesia comic information leaflet reduced preoperative anxiety levels of children undergoing major surgery. Secondary objectives were to determine whether the level of understanding of participants and other risk factors influence STAIC-S (State-Trait Anxiety Inventory for Children-State subscale) score in children. We performed a randomized controlled parallel-group trial comparing preoperative anxiety between two groups of children aged >6 and <17 yr. Before surgery, the intervention group received a comic information leaflet at home in addition to routine information given by the anaesthetist at least 1 day before surgery. The control group received the routine information only. The outcome measure was the difference between STAIC-S scores measured before any intervention and after the anaesthetist's visit. A multiple regression analysis was performed to explore the influence of the level of education, the anxiety of parents, and the childrens' intelligence quotient on STAIC-S scores. One hundred and fifteen children were randomized between April 2009 and April 2013. An intention-to-treat analysis on data from 111 patients showed a significant reduction (P=0.002) in STAIC-S in the intervention group (n=54, mean=-2.2) compared with the control group (n=57, mean=0.90). The multiple regression analysis did not show any influence on STAIC-S scores of the level of education, parental anxiety, or the intelligence quotient of the children. A paediatric anaesthesia comic information leaflet was a cheap and effective means of reducing preoperative anxiety, measured by STAIC-S, in children. NCT 00841022. © The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Infective endocarditis presenting as an isolated aneurysm of the posterior mitral leaflet.

    PubMed

    Unger, Philippe; Antoine, Martine; Hastir, Delfyne; Dedobbeleer, Chantal; Leeman, Marc

    2013-06-01

    We describe the case of a 64-year-old woman in whom an aneurysm located on the posterior mitral leaflet was detected. Blood cultures grew methicillin-sensitive Staphylococcus epidermidis, and histologic examination of the operative specimen showed polymorphonuclear neutrophilic infiltration of the valve wall associated with fibrin and necrosis, consistent with a diagnosis of endocarditis. The posterior mitral location of the aneurysm and the absence of vegetation are exceptionally rare in this setting. This case demonstrates that a mitral aneurysm may be the sole cardiac presentation of infective endocarditis. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  14. Intentional Laceration of the Anterior Mitral Valve Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement: Pre-Clinical Findings.

    PubMed

    Khan, Jaffar M; Rogers, Toby; Schenke, William H; Mazal, Jonathan R; Faranesh, Anthony Z; Greenbaum, Adam B; Babaliaros, Vasilis C; Chen, Marcus Y; Lederman, Robert J

    2016-09-12

    The authors propose a novel transcatheter transection of the anterior mitral leaflet to prevent iatrogenic left ventricular outflow tract (LVOT) obstruction during transcatheter mitral valve replacement (TMVR). LVOT obstruction is a life-threatening complication of TMVR caused by septal displacement of the anterior mitral leaflet. In vivo procedures in swine were guided by biplane x-ray fluoroscopy and intracardiac echocardiography. Retrograde transaortic 6-F guiding catheters straddled the anterior mitral leaflet. A stiff 0.014-inch guidewire with polymer jacket insulation was electrified and advanced from the LVOT, through the A2 leaflet base, into the left atrium. The wire was snared and externalized, forming a loop that was energized and withdrawn to lacerate the anterior mitral leaflet. The anterior mitral leaflet was successfully lacerated in 7 live and 1 post-mortem swine under heparinization. Lacerations extended to 89 ± 19% of leaflet length and were located within 0.5 ± 0.4 mm of leaflet centerline. The chordae were preserved and retracted the leaflet halves away from the LVOT. LVOT narrowing after benchtop TMVR was significantly reduced with intentional laceration of the anterior mitral leaflet to prevent LVOT obstruction than without (65 ± 10% vs. 31 ± 18% of pre-implantation diameter, p < 0.01). The technique caused mean blood pressure to fall (from 54 ± 6 mm Hg to 30 ± 4 mm Hg, p < 0.01), but blood pressure remained steady until planned euthanasia. No collateral tissue injury was identified on necropsy. Using simple catheter techniques, the anterior mitral valve leaflet was transected. Cautiously applied in patients, this strategy can prevent anterior mitral leaflet displacement and LVOT obstruction caused by TMVR. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  15. Effect of educational leaflets and questions on knowledge of contraception in women taking the combined contraceptive pill: randomised controlled trial.

    PubMed

    Little, P; Griffin, S; Kelly, J; Dickson, N; Sadler, C

    1998-06-27

    To assess whether provision of educational leaflets or questions on contraception improves knowledge of contraception in women taking the combined contraceptive pill. Randomisation of women into three groups according to type of educational leaflet on contraceptive information. These groups were subdivided into two on the basis of questions on contraception asked by the doctor or practice nurse. The women were followed up by postal questionnaire 3 months later. 15 general practices in South and West region. 636 women attending check up appointment for repeat prescription of the combined contraceptive pill. Knowledge of: factors causing pill failure, subsequent action, emergency contraception, and all the rules (pill rules) that apply to the contraceptive pill. 523 women returned completed questionnaires (response rate 82%). Knowledge of contraception with no intervention was low with only 10 (12%) women knowing all the pill rules. Educational intervention had a highly significant effect on knowledge of: factors causing pill failure (likelihood ratio chi2=22); subsequent action (21); emergency contraception (24); and all the pill rules (22) (P<0.01 in all cases). Improvement in knowledge of all the pill rules occurred with provision of the summary leaflet (28% knew all the rules, adjusted odds ratio 4.04, 95% confidence interval 1.68 to 9.75), the Family Planning Association's leaflet (27%, 3.43, 1.45 to 8.09), and asking questions (26%, 3.03, 1.30 to 7.00). Asking questions in addition to provision of leaflets improved knowledge of contraception further for the summary leaflet (39%, 6.81, 2.85 to 16.27) but not for the Family Planning Association leaflet (21%, 2.58, 1.07 to 6.18). Women attending check ups for repeat prescriptions of the contraceptive pill should be provided with educational leaflets on contraception or asked relevant questions to help improve their knowledge of contraception. Asking questions in addition to providing a summary leaflet is time

  16. Resolution and reproducibility of BOLD and perfusion functional MRI at 3.0 Tesla.

    PubMed

    van Gelderen, Peter; W H Wu, Carolyn; de Zwart, Jacco A; Cohen, Leonardo; Hallett, Mark; Duyn, Jeff H

    2005-09-01

    Visual and somatosensory activation studies were performed on normal subjects to compare the spatial discrimination and reproducibility between functional MRI (fMRI) methods based on blood oxygen level-dependent (BOLD) and perfusion contrast. To allow simultaneous measurement of BOLD and perfusion contrast, a dedicated MRI acquisition technique was developed. Repeated experiments of sensory stimulation of single digits of the right hand showed an average variability of activation amplitude of 25% for BOLD data, and a significantly lower variability of 21% for perfusion data. No significant difference in the variability of the locus of activity was observed between the BOLD and perfusion data. In somatotopy experiments, digits II and V were subjected to passive sensory stimulation. Both the BOLD and perfusion data showed substantial overlap in the activation patterns from the two digits. In a retinotopy study, two stimuli were alternated to excite different patches of V1. Again there was substantial overlap between the activation patterns from both stimuli, although the perfusion performed somewhat better than the BOLD method. Particularly for the visual studies, the overlap in activation patterns was more than expected based on the fine-scale retinotopic mapping of cortical activity, suggesting that both BOLD and perfusion contrast mechanisms contribute substantially to the point-spread function (PSF).

  17. Hydrothermal Pretreatment of Date Palm (Phoenix dactylifera L.) Leaflets and Rachis to Enhance Enzymatic Digestibility and Bioethanol Potential

    PubMed Central

    Fang, Chuanji; Schmidt, Jens Ejbye; Cybulska, Iwona; Brudecki, Grzegorz P.; Frankær, Christian Grundahl; Thomsen, Mette Hedegaard

    2015-01-01

    Date palm residues are one of the most promising lignocellulosic biomass for bioethanol production in the Middle East. In this study, leaflets and rachis were subjected to hydrothermal pretreatment to overcome the recalcitrance of the biomass for enzymatic conversion. Evident morphological, structural, and chemical changes were observed by scanning electron microscopy, X-ray diffraction, and infrared spectroscopy after pretreatment. High glucan (>90% for both leaflets and rachis) and xylan (>75% for leaflets and >79% for rachis) recovery were achieved. Under the optimal condition of hydrothermal pretreatment (210°C/10 min) highly digestible (glucan convertibility, 100% to leaflets, 78% to rachis) and fermentable (ethanol yield, 96% to leaflets, 80% to rachis) solid fractions were obtained. Fermentability test of the liquid fractions proved that no considerable inhibitors to Saccharomyces cerevisiae were produced in hydrothermal pretreatment. Given the high sugar recovery, enzymatic digestibility, and ethanol yield, production of bioethanol by hydrothermal pretreatment could be a promising way of valorization of date palm residues in this region. PMID:26347878

  18. Tricuspid Anterior Leaflet Replacement with Autologous Pericardium and Polytetrafluoroethylene Chordae, Followed by Edge-to-Edge Repair

    PubMed Central

    García-Rinaldi, Raúl

    2007-01-01

    Treatment of endocarditis of the tricuspid valve is very complex. Valvectomy without replacement can result in significant postoperative morbidity, and replacement is hazardous due to the possibility of prosthetic infection. Repair of the tricuspid valve is the best alternative. Many ingenious methods have been devised to repair the tricuspid valve in patients with infective endocarditis. However, repair of the endocarditic anterior leaflet presents a difficult surgical problem. We have developed a technique to replace the central portion of the anterior leaflet, in which most of the leaflet is excised and replaced with autologous pericardium. By preserving a small rim of the leaflet, we preserve the lateral and medial chordal attachments. Supplemental neochordae are created with polytetrafluoroethylene sutures. An edge-to-edge repair is used to correct residual insufficiency of the valve. We have used this technique in 4 patients. One patient died 1 month after surgery, but with a competent tricuspid valve. Three patients are now alive, 48, 34, and 1.5 months after surgery. Their tricuspid valves are functional, moving well, and competent. We conclude that the centrally infected anterior leaflet of the tricuspid valve can be replaced with autologous pericardium. The implantation of polytetrafluoroethylene neochordae and edge-to-edge repair can be used to achieve valve competence. Short- and medium-term follow-up in patients who have been treated with these techniques demonstrates that the valve remains fully mobile and competent. PMID:17948081

  19. Mitral Valve Replacement After Failed Mitral Ring Insertion With or Without Leaflet/Chordal Repair for Pure Mitral Regurgitation.

    PubMed

    Roberts, William C; Moore, Meagan; Ko, Jong Mi; Hamman, Baron L

    2016-06-01

    Mitral repair operations for correction of pure mitral regurgitation (MR) are generally quite successful. Occasionally, however, the reparative procedure incompletely corrects the MR or the MR recurs. From March 1993 to January 2016, twenty nine patients had mitral valve replacement after the initial mitral repair operation, and observations in them were analyzed. All 29 patients at the repair operation had an annular ring inserted and later (<1 year in 6 and >1 year in 21) mitral valve replacement. The cause of the MR before the repair operation appears to have been prolapse in 16 patients (55%), secondary (functional) in 12 (41%) (ischemic in 5), and infective endocarditis which healed in 1 (3%). At the replacement operation the excised anterior mitral leaflet was thickened in all 29 patients. Some degree of stenosis appeared to have been present in 16 of the 29 patients before the replacement operation, although only 10 had an echocardiographic or hemodynamic recording of a transvalvular gradient; at least 11 patients had restricted motion of the posterior mitral leaflet; 10, ring dehiscence; 2, severe hemolysis; and 2, left ventricular outflow obstruction. In conclusion, there are multiple reasons for valve replacement after earlier mitral repair. Uniformly, at the time of the replacement, the mitral leaflets were thickened by fibrous tissue. Measurement of the area enclosed by the 360° rings and study of the excised leaflet suggest that the ring itself may have contributed to the leaflet scarring and development of some transmitral stenosis.

  20. Architectural trends in the human normal and bicuspid aortic valve leaflet and its relevance to valve disease.

    PubMed

    Aggarwal, Ankush; Ferrari, Giovanni; Joyce, Erin; Daniels, Michael J; Sainger, Rachana; Gorman, Joseph H; Gorman, Robert; Sacks, Michael S

    2014-05-01

    The bicuspid aortic valve (AV) is the most common cardiac congenital anomaly and has been found to be a significant risk factor for developing calcific AV disease. However, the mechanisms of disease development remain unclear. In this study we quantified the structure of human normal and bicuspid leaflets in the early disease stage. From these individual leaflet maps average fiber structure maps were generated using a novel spline based technique. Interestingly, we found statistically different and consistent regional structures between the normal and bicuspid valves. The regularity in the observed microstructure was a surprising finding, especially for the pathological BAV leaflets and is an essential cornerstone of any predictive mathematical models of valve disease. In contrast, we determined that isolated valve interstitial cells from BAV leaflets show the same in vitro calcification pathways as those from the normal AV leaflets. This result suggests the VICs are not intrinsically different when isolated, and that external features, such as abnormal microstructure and altered flow may be the primary contributors in the accelerated calcification experienced by BAV patients.

  1. Quantification and Analysis of Leaflet Flutter on Biological Prosthetic Cardiac Valves.

    PubMed

    Avelar, Artur H de F; Canestri, Jean A; Bim, Camila; Silva, Maíra G M; Huebner, Rudolf; Pinotti, Marcos

    2017-09-01

    The use of porcine or bovine pericardium biological cardiac valves has as its main disadvantage a relatively short lifespan, with failures due to calcification and fatigue. Increasing these valves' durability constitutes a great challenge. An understudied phenomenon is the effect of flutter, an oscillation of the leaflets that can cause regurgitation and accelerate calcification and fatigue. As a starting point to study how to reduce or prevent these oscillations, a method was developed to quantify the flutter frequencies occurring at the point of the valve's full opening. On a test bench that simulates the heart flow, the cusp behaviors of eight biological valves were filmed with a high speed camera at 2000 frames per second at different flow rates and motion capture software obtained the frequencies and amplitudes of the vibrations of each leaflet. Oscillations in the range of 200 Hz with average amplitudes of 0.4 mm were found; larger nominal diameter valves obtained lower values, and bovine pericardial valves had superior performance compared to porcine valves. A dimensionless analysis was performed to find a relationship between the geometric and mechanical properties of the valves with the critical speed of the onset of fluttering. This relationship inspired a method to predict whether flutter will occur in the bioprosthesis. This method is a new tool for the consideration of maximizing the life of prosthetic valves. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  2. Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes

    SciTech Connect

    Smith, Jeremy C.; Cheng, Xiaolin; Nickels, Jonathan D.

    2015-07-29

    Understanding of cell membrane organization has evolved significantly from the classic fluid mosaic model. It is now recognized that biological membranes are highly organized structures, with differences in lipid compositions between inner and outer leaflets and in lateral structures within the bilayer plane, known as lipid rafts. These organizing principles are important for protein localization and function as well as cellular signaling. However, the mechanisms and biophysical basis of lipid raft formation, structure, dynamics and function are not clearly understood. One key question, which we focus on in this review, is how lateral organization and leaflet compositional asymmetry are coupled. Detailed information elucidating this question has been sparse because of the small size and transient nature of rafts and the experimental challenges in constructing asymmetric bilayers. Resolving this mystery will require advances in both experimentation and modeling. We discuss here the preparation of model systems along with experimental and computational approaches that have been applied in efforts to address this key question in membrane biology. Furthermore, we seek to place recent and future advances in experimental and computational techniques in context, providing insight into in-plane and transverse organization of biological membranes.

  3. A mirror code for protein-cholesterol interactions in the two leaflets of biological membranes

    PubMed Central

    Fantini, Jacques; Di Scala, Coralie; Evans, Luke S.; Williamson, Philip T. F.; Barrantes, Francisco J.

    2016-01-01

    Cholesterol controls the activity of a wide range of membrane receptors through specific interactions and identifying cholesterol recognition motifs is therefore critical for understanding signaling receptor function. The membrane-spanning domains of the paradigm neurotransmitter receptor for acetylcholine (AChR) display a series of cholesterol consensus domains (referred to as “CARC”). Here we use a combination of molecular modeling, lipid monolayer/mutational approaches and NMR spectroscopy to study the binding of cholesterol to a synthetic CARC peptide. The CARC-cholesterol interaction is of high affinity, lipid-specific, concentration-dependent, and sensitive to single-point mutations. The CARC motif is generally located in the outer membrane leaflet and its reverse sequence CRAC in the inner one. Their simultaneous presence within the same transmembrane domain obeys a “mirror code” controlling protein-cholesterol interactions in the outer and inner membrane leaflets. Deciphering this code enabled us to elaborate guidelines for the detection of cholesterol-binding motifs in any membrane protein. Several representative examples of neurotransmitter receptors and ABC transporters with the dual CARC/CRAC motifs are presented. The biological significance and potential clinical applications of the mirror code are discussed. PMID:26915987

  4. Comparative anatomy of leaflets of Zamia acuminata and Z. pseudomonticola (Zamiaceae) in Costa Rica.

    PubMed

    Acuña-Castillo, Rafael; Marin-Méndez, Walter

    2013-06-01

    The genus Zamia is morphologically and ecologically the most diverse of the order Cycadales. Throughout its history this genus has been restricted to the New World and is presently almost entirely restricted to the Neotropics. Unusual anatomical traits of the leaflets, such as the sunken stomata and thick cuticle, are common in this and related genera. The objective of this research was to study and compare the leaflet anatomy of Zamia acuminata and Z pseudomonticola and establish possible phylogenetic relationships between the anatomical traits and the near relatives of these species. The leaf material was obtained from living plants and then processed for electron microscopy study. We found that both species are very similar to each other and to Z fairchildiana, and that they share several unusual traits with other species of the genus, such as the parenchyma morphology, the spatial distribution of tissues between the veins and the stomata morphology. The main differences between these species were seen in their fiber clusters and in the abundance oftrichome basal cells on the epidermis. The anatomical similarities between the three species could be the result of their close phylogenetic relationship and the divergences between them could be the result of recent speciation during the Pleistocene, resulting from geological changes in Southern Costa Rica.

  5. Tissue-engineered fibrin-based heart valve with a tubular leaflet design.

    PubMed

    Weber, Miriam; Heta, Eriona; Moreira, Ricardo; Gesche, Valentine N; Schermer, Thomas; Frese, Julia; Jockenhoevel, Stefan; Mela, Petra

    2014-04-01

    The general approach in heart valve tissue engineering is to mimic the shape of the native valve in the attempt to recreate the natural haemodynamics. In this article, we report the fabrication of the first tissue-engineered heart valve (TEHV) based on a tubular leaflet design, where the function of the leaflets of semilunar heart valves is performed by a simple tubular construct sutured along a circumferential line at the root and at three single points at the sinotubular junction. The tubular design is a recent development in pericardial (nonviable) bioprostheses, which has attracted interest because of the simplicity of the construction and the reliability of the implantation technique. Here we push the potential of the concept further from the fabrication and material point of view to realize the tube-in-tube valve: an autologous, living HV with remodelling and growing capability, physiological haemocompatibility, simple to construct and fast to implant. We developed two different fabrication/conditioning procedures and produced fibrin-based constructs embedding cells from the ovine umbilical cord artery according to the two different approaches. Tissue formation was confirmed by histology and immunohistology. The design of the tube-in-tube foresees the possibility of using a textile coscaffold (here demonstrated with a warp-knitted mesh) to achieve enhanced mechanical properties in vision of implantation in the aortic position. The tube-in-tube represents an attractive alternative to the conventional design of TEHVs aiming at reproducing the valvular geometry.

  6. Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes

    DOE PAGES

    Smith, Jeremy C.; Cheng, Xiaolin; Nickels, Jonathan D.

    2015-07-29

    Understanding of cell membrane organization has evolved significantly from the classic fluid mosaic model. It is now recognized that biological membranes are highly organized structures, with differences in lipid compositions between inner and outer leaflets and in lateral structures within the bilayer plane, known as lipid rafts. These organizing principles are important for protein localization and function as well as cellular signaling. However, the mechanisms and biophysical basis of lipid raft formation, structure, dynamics and function are not clearly understood. One key question, which we focus on in this review, is how lateral organization and leaflet compositional asymmetry are coupled.more » Detailed information elucidating this question has been sparse because of the small size and transient nature of rafts and the experimental challenges in constructing asymmetric bilayers. Resolving this mystery will require advances in both experimentation and modeling. We discuss here the preparation of model systems along with experimental and computational approaches that have been applied in efforts to address this key question in membrane biology. Furthermore, we seek to place recent and future advances in experimental and computational techniques in context, providing insight into in-plane and transverse organization of biological membranes.« less

  7. Tissue-Engineered Fibrin-Based Heart Valve with a Tubular Leaflet Design

    PubMed Central

    Weber, Miriam; Heta, Eriona; Moreira, Ricardo; Gesche, Valentine N.; Schermer, Thomas; Frese, Julia

    2014-01-01

    The general approach in heart valve tissue engineering is to mimic the shape of the native valve in the attempt to recreate the natural haemodynamics. In this article, we report the fabrication of the first tissue-engineered heart valve (TEHV) based on a tubular leaflet design, where the function of the leaflets of semilunar heart valves is performed by a simple tubular construct sutured along a circumferential line at the root and at three single points at the sinotubular junction. The tubular design is a recent development in pericardial (nonviable) bioprostheses, which has attracted interest because of the simplicity of the construction and the reliability of the implantation technique. Here we push the potential of the concept further from the fabrication and material point of view to realize the tube-in-tube valve: an autologous, living HV with remodelling and growing capability, physiological haemocompatibility, simple to construct and fast to implant. We developed two different fabrication/conditioning procedures and produced fibrin-based constructs embedding cells from the ovine umbilical cord artery according to the two different approaches. Tissue formation was confirmed by histology and immunohistology. The design of the tube-in-tube foresees the possibility of using a textile coscaffold (here demonstrated with a warp-knitted mesh) to achieve enhanced mechanical properties in vision of implantation in the aortic position. The tube-in-tube represents an attractive alternative to the conventional design of TEHVs aiming at reproducing the valvular geometry. PMID:23829551

  8. Interleaflet Coupling, Pinning, and Leaflet Asymmetry-Major Players in Plasma Membrane Nanodomain Formation.

    PubMed

    Fujimoto, Toyoshi; Parmryd, Ingela

    2016-01-01

    The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence.

  9. Planar biaxial creep and stress relaxation of the mitral valve anterior leaflet.

    PubMed

    Grashow, Jonathan S; Sacks, Michael S; Liao, Jun; Yoganathan, Ajit P

    2006-10-01

    A fundamental assumption in mitral valve (MV) therapies is that a repaired or replaced valve should mimic the functionality of the native valve as closely as possible. Thus, improvements in valvular treatments are dependent on the establishment of a complete understanding of the function and mechanical properties of the native normal MV. In a recent study [Grashow et al. ABME 34(2), 2006] we demonstrated that the planar biaxial stress-strain relationship of the MV anterior leaflet (MVAL) exhibited minimal hysteresis and a stress-strain response independent of strain rate, suggesting that MVAL could be modeled as a "quasi-elastic" material. The objective of our current study was to expand these results to provide a more complete picture of the time-dependent mechanical properties of the MVAL. To accomplish this, biaxial stress-relaxation and creep studies were performed on porcine MVAL specimens. Our primary finding was that while the MVAL leaflet exhibited significant stress relaxation, it exhibited negligible creep over the 3-h test. These results furthered our assertion that the MVAL functionally behaves not as a linear or non-linear viscoelastic material, but as an anisotropic quasi-elastic material. These results appear to be unique in the soft tissue literature; suggesting that valvular tissues are unequalled in their ability to withstand significant loading without time-dependent material effects. Moreover, insight into these specialized characteristics can help guide and inform efforts directed toward surgical repair and engineered valvular tissue replacements.

  10. Evaluation of the Readability of Dermatological Postoperative Patient Information Leaflets Across England.

    PubMed

    Hunt, William T N; McGrath, Emily J

    2016-06-01

    Postoperative patient information leaflets (PILs) provide important guidance to patients after skin surgery. Readability is a method of evaluating information for text comprehension. The recommended level for PIL readability is US grade ≤6. To evaluate the readability of public English dermatological postoperative PILs. All dermatology departments in England were requested to provide their postoperative PILs. Patient information leaflets were evaluated using Readability Studio (Oleander Software, Vandalia, OH). Two preselected parameters were also noted: whether the PIL was doctor or nurse-written, and whether the PIL was Information Standard hallmarked. Eighty-five of one hundred thirty (65.4%) of PILs were evaluated. Only 29.4% of the PILs were grade level ≤6 with Flesch-Kincaid. The mean readability levels were 7.8 for Flesch-Kincaid, 67 for Flesch reading ease, 10.5 for Simple Measure of Gobbledygook (SMOG), 9.4 for Gunning-Fog, 8 for Fry, and 9.8 for FORCAST. No instruments demonstrated a significant difference between doctor (6) and nurse-written (7) PILs. Two instruments found that the 3 Information Standard hallmarked PILs had a higher (harder) readability than ordinary PILs (n = 82) (Gunning-Fog, p = .029*; SMOG p = .049*). Most English postoperative dermatological PILs' readability levels exceed recommendations (US grade ≤6). Departmental PILs should be reviewed to ensure that they are comprehensible to their patients.

  11. Interleaflet Coupling, Pinning, and Leaflet Asymmetry—Major Players in Plasma Membrane Nanodomain Formation

    PubMed Central

    Fujimoto, Toyoshi; Parmryd, Ingela

    2017-01-01

    The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence. PMID:28119914

  12. A mirror code for protein-cholesterol interactions in the two leaflets of biological membranes

    NASA Astrophysics Data System (ADS)

    Fantini, Jacques; di Scala, Coralie; Evans, Luke S.; Williamson, Philip T. F.; Barrantes, Francisco J.

    2016-02-01

    Cholesterol controls the activity of a wide range of membrane receptors through specific interactions and identifying cholesterol recognition motifs is therefore critical for understanding signaling receptor function. The membrane-spanning domains of the paradigm neurotransmitter receptor for acetylcholine (AChR) display a series of cholesterol consensus domains (referred to as “CARC”). Here we use a combination of molecular modeling, lipid monolayer/mutational approaches and NMR spectroscopy to study the binding of cholesterol to a synthetic CARC peptide. The CARC-cholesterol interaction is of high affinity, lipid-specific, concentration-dependent, and sensitive to single-point mutations. The CARC motif is generally located in the outer membrane leaflet and its reverse sequence CRAC in the inner one. Their simultaneous presence within the same transmembrane domain obeys a “mirror code” controlling protein-cholesterol interactions in the outer and inner membrane leaflets. Deciphering this code enabled us to elaborate guidelines for the detection of cholesterol-binding motifs in any membrane protein. Several representative examples of neurotransmitter receptors and ABC transporters with the dual CARC/CRAC motifs are presented. The biological significance and potential clinical applications of the mirror code are discussed.

  13. Intrahemispheric Perfusion in Chronic Stroke-Induced Aphasia

    PubMed Central

    Walenski, Matthew; Chen, YuFen; Caplan, David; Rapp, Brenda; Grunewald, Kristin; Nunez, Mia; Zinbarg, Richard; Parrish, Todd B.

    2017-01-01

    Stroke-induced alterations in cerebral blood flow (perfusion) may contribute to functional language impairments and recovery in chronic aphasia. Using MRI, we examined perfusion in the right and left hemispheres of 35 aphasic and 16 healthy control participants. Across 76 regions (38 per hemisphere), no significant between-subjects differences were found in the left, whereas blood flow in the right was increased in the aphasic compared to the control participants. Region-of-interest (ROI) analyses showed a varied pattern of hypo- and hyperperfused regions across hemispheres in the aphasic participants; however, there were no significant correlations between perfusion values and language abilities in these regions. These patterns may reflect autoregulatory changes in blood flow following stroke and/or increases in general cognitive effort, rather than maladaptive language processing. We also examined blood flow in perilesional tissue, finding the greatest hypoperfusion close to the lesion (within 0–6 mm), with greater hypoperfusion in this region compared to more distal regions. In addition, hypoperfusion in this region was significantly correlated with language impairment. These findings underscore the need to consider cerebral perfusion as a factor contributing to language deficits in chronic aphasia as well as recovery of language function. PMID:28357141

  14. Viable neurons with luxury perfusion in hydrocephalus.

    PubMed

    Wong, C Y; Luciano, M G; MacIntyre, W J; Brunken, R C; Hahn, J F; Go, R T

    1997-09-01

    A woman with hydrocephalus due to aqueductal stenosis had functional imaging of cerebral perfusion and metabolism to demonstrate the effects of endoscopic third ventriculostomy--a new form of internal surgical shunting. Technetium-99m-ECD SPECT and 18F-FDG PET showed regional luxury perfusion at the left frontal region. Three months after a successful third ventriculostomy, a repeated imaging of cerebral perfusion and metabolism showed resolution of luxury perfusion and global improvement of both perfusion and metabolism. This concurred with postoperative clinical improvement. The paired imaging of cerebral perfusion and metabolism provides more information than just imaging perfusion or metabolism. Thus, the detection of perfusion and metabolism mismatch may open a new window of opportunity for surgical intervention.

  15. Use of a tantalum-178 generator and a multiwire gamma camera to study the effect of the Mueller maneuver on left ventricular performance: comparison to hemodynamics and single photon emission computed tomography perfusion patterns.

    PubMed

    Gioia, G; Lin, B; Katz, R; DiMarino, A J; Ogilby, J D; Cassel, D; DePace, N L; Heo, J; Iskandrian, A S

    1995-11-01

    During the Mueller maneuver, there is a decrease in intrathoracic pressure and an increase in transmural left ventricular pressure. The changes in loading conditions cause transient left ventricular dysfunction. This study examined the effects of the Mueller maneuver on left ventricular performance using tantalum (Ta)-178 (half-life 9.3 min) and a multiwire gamma camera. First-pass radionuclide angiograms were obtained at baseline and during Mueller maneuver in 41 patients aged 58 +/- 10 years. In 34 patients, stress single photon emission computed tomography (SPECT) myocardial perfusion imaging with thallium-201 or sestamibi was also performed. Hemodynamic measurements during the Mueller maneuver (n = 10) showed a decrease in systemic pressure (139 +/- 25 mm Hg vs 123 +/- 24 mm Hg, p < 0.001) and pulmonary artery pressure (24 +/- 6 mm Hg vs 14 +/- 12 mm Hg, p = 0.01) and an increase in heart rate (67 +/- 10 bpm vs 75 +/- 14 beats/min, p = 0.001). Among the 34 patients who had perfusion imaging, the left ventricular ejection fraction remained unchanged or increased in 17 patients (group 1) (48% +/- 19% vs 49% +/- 21%, p not significant) and decreased (> or = 5%) in 17 patients (group 2) (55% +/- 13% vs 40% +/- 16%, p = 0.001). The stress SPECT images showed no or only fixed defects in 11 (65%) patients in group 1 and 3 (18%) patients in group 2 (p = 0.02), and reversible defects in 6 (35%) patients in group 1 and 14 (82%) patients in group 2 (p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

  16. The pediatric template of brain perfusion

    PubMed Central

    Avants, Brian B; Duda, Jeffrey T; Kilroy, Emily; Krasileva, Kate; Jann, Kay; Kandel, Benjamin T; Tustison, Nicholas J; Yan, Lirong; Jog, Mayank; Smith, Robert; Wang, Yi; Dapretto, Mirella; Wang, Danny J J

    2015-01-01

    Magnetic resonance imaging (MRI) captures the dynamics of brain development with multiple modalities that quantify both structure and function. These measurements may yield valuable insights into the neural patterns that mark healthy maturation or that identify early risk for psychiatric disorder. The Pediatric Template of Brain Perfusion (PTBP) is a free and public neuroimaging resource that will help accelerate the understanding of childhood brain development as seen through the lens of multiple modality neuroimaging and in relation to cognitive and environmental factors. The PTBP uses cross-sectional and longitudinal MRI to quantify cortex, white matter, resting state functional connectivity and brain perfusion, as measured by Arterial Spin Labeling (ASL), in 120 children 7–18 years of age. We describe the PTBP and show, as a demonstration of validity, that global summary measurements capture the trajectories that demarcate critical turning points in brain maturation. This novel resource will allow a more detailed understanding of the network-level, structural and functional landmarks that are obtained during normal adolescent brain development. PMID:25977810

  17. The pediatric template of brain perfusion.

    PubMed

    Avants, Brian B; Duda, Jeffrey T; Kilroy, Emily; Krasileva, Kate; Jann, Kay; Kandel, Benjamin T; Tustison, Nicholas J; Yan, Lirong; Jog, Mayank; Smith, Robert; Wang, Yi; Dapretto, Mirella; Wang, Danny J J

    2015-01-01

    Magnetic resonance imaging (MRI) captures the dynamics of brain development with multiple modalities that quantify both structure and function. These measurements may yield valuable insights into the neural patterns that mark healthy maturation or that identify early risk for psychiatric disorder. The Pediatric Template of Brain Perfusion (PTBP) is a free and public neuroimaging resource that will help accelerate the understanding of childhood brain development as seen through the lens of multiple modality neuroimaging and in relation to cognitive and environmental factors. The PTBP uses cross-sectional and longitudinal MRI to quantify cortex, white matter, resting state functional connectivity and brain perfusion, as measured by Arterial Spin Labeling (ASL), in 120 children 7-18 years of age. We describe the PTBP and show, as a demonstration of validity, that global summary measurements capture the trajectories that demarcate critical turning points in brain maturation. This novel resource will allow a more detailed understanding of the network-level, structural and functional landmarks that are obtained during normal adolescent brain development.

  18. Left ventricular wall function abnormalities in patients with ankylosing spondylitis evaluated by gated myocardial perfusion scintigraphy.

    PubMed

    Yalcin, H; Guler, H; Gunay, E; Yeral, N; Turhanoglu, A; Bolaç, E; Yalcin, F

    2011-01-01

    Ankylosing spondilitis (AS) is a chronic inflammatory disease with prominent inflammation in joints and extraarticular organs. AS patients have approximately two times more risk of mortality than the normal population. One reason for this increase in mortality is increased cardiovascular risk. In this study, we have aimed to evaluate myocardial perfusion and left ventricular function using (99m)Tc-MIBI gated myocardial perfusion single photon emission computed tomography (SPECT). The study group consisted of 28 AS patients (19 men, 9 women), and mean age 39.46±10.98 years. All patients underwent (99m)Tc-MIBI gated myocardial perfusion SPECT with the same day protocol. We detected various risk factors including smoking habits in 12, family history of cardiovascular disease in 12, hypertension in 3, hyperlipidemia in 9 patients. We performed a myocardial perfusion SPECT for each patient and found normal perfusion pattern in SPECT images. Out of 28 patients, eight patients had normal perfusion but wall motion abnormalities. We detected that myocardial perfusion is preserved in the patients with AS. However, left ventricular wall motion abnormalities are seen. We concluded that ankylosing spondylitis may be associated with microvascular dysfunction and gated myocardial perfusion scintigraphy could be valuable in AS patients for the evaluation of LV function even if the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score are low and the disease duration shorter. Copyright © 2010 Elsevier España, S.L. and SEMNIM. All rights reserved.

  19. Consumer’s Perception on Design and Layout of Consumer Medical Information Leaflets on Obesity and Lipid Lowering Drugs

    PubMed Central

    Mathew, Elizabeth M.; Rajiah, Kingston; Sharma, Krishana Kumar

    2013-01-01

    Background: Printed education materials are often used to augment healthcare professional’s verbal information to consumers so it serves as an important component of symptom management. They also enhance the teaching process and can be used by consumers as a home reference. Objective: This study was aimed to interpret consumers’ perception on Consumer Medical Information Leaflets (CMILs) on obesity and lipid lowering drugs, on design and layout using the standard method such as Baker Able Leaflet Design (BALD). Material and Methods: Convenience sampling was done. The study was conducted over a period of 3 years in community pharmacy settings in Tamil Nadu, India. The Consumer Medical Information Leaflets (CMILs) were randomly collected from different community pharmacies. Total of 19 CMILs which are commonly used by the consumers were collected and CMILs were assessed using BALD assessment tool Results: According to BALD assessment (46.28%) leaflets were rated as ‘above standard’ and (53.72) leaflets were rated as ‘standard or poor’ in layout and design since their scores were less than 25. This shows that this issue may be important from the patient’s perspective, which may discourage patient from actually reading the CMILs. Conclusion: In India, generally CMILs are continued to be prepared in English and with higher proportion of consumers with English illiteracy. CMILs, which are prepared without taking consideration of reading level of consumers and proper layout and design, may not achieve the intended purpose. This is an important aspect that any company has to reckon while preparing leaflets and at least in some major local languages in which CMILs have to be prepared. PMID:24551641

  20. Randomised controlled trial using smartphone website vs leaflet to support antenatal perineal massage practice for pregnant women.

    PubMed

    Takeuchi, Shoko; Horiuchi, Shigeko

    2016-10-01

    In Japan, the rate of pregnant women who practice antenatal perineal massage was only 15.1%. The aim of this study was to develop and evaluate a smartphone website and a leaflet to support antenatal perineal massage practice for primiparous women. In a randomised control trial, 161 primiparous women were randomly assigned to a smartphone website group (n=81) or a leaflet group (n=80). Data analysis were by per protocol analysis and intention to treat analysis. Of the 161 women participants, 47 in the smartphone website group and 49 in the leaflet group completed all questionnaires. Primary outcome was continuance rate (three times a week over a three week period) of antenatal perineal massage practice. The rates by a per protocol analysis were 51.1% in the smartphone website group and 51.0% in the leaflet group, respectively. There was no significant difference between the groups. Moreover, the rates by an intention to treat analysis were 29.6% in the smartphone website group and 31.3% in the leaflet group, respectively. There was also no significant difference between the groups. There were no significant differences in the evaluation of perineal massage, childbirth self-efficacy, satisfaction with efforts towards childbirth, and perineal outcomes following childbirth which were measured as secondary outcomes between the groups. There was no significant difference in continuance rate of antenatal perineal massage practice between those using a smartphone website and those with a leaflet, however, the rate was better than no instructions. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Comparing the effect of a leaflet and a movie in preventing tick bites and Lyme disease in The Netherlands.

    PubMed

    Beaujean, Desirée Jacqueline Mathieu Angélique; Crutzen, Rik; Gassner, Fedor; Ameling, Caroline; Wong, Albert; van Steenbergen, James Everard; Ruwaard, Dirk

    2016-06-10

    Lyme disease (LD) has become the most common vector borne illness in the Northern hemisphere. Prevention relies predominantly on fostering protective behaviors (e.g., avoiding tick areas, using protective clothing and repellent, and doing routine tick checks post-exposure). The objective of this study was to evaluate the effectiveness (in terms of knowledge, perceived severity and susceptibility, self-efficacy, response efficacy, intention, and behavior over time) and appreciation of a leaflet and a movie as tools for informing the public in the Netherlands about ticks and LD protective behaviors. Participants (1,677 at t1 and 361 extra at t2) were members of a representative Internet panel (adults aged 18 years and above). A four group randomized controlled design was used to test the effect of an information leaflet and a movie (two intervention groups), compared to a control group and a follow-up only control group. Data were collected over two periods: July 15-29, 2013 (t1) and at follow-up 4 weeks later, August 16-31, 2013 (t2). Post-intervention results show all respondents in all groups possess good general basic knowledge of ticks and LD. Respondents in both the leaflet and movie groups knew more than respondents in the control group, and had greater awareness of best practices after a tick bite. Intention to perform protective behavior in future was stronger among respondents in the intervention groups. While respondents generally appreciated both the movie and the leaflet, they found the movie ran too long. Follow-up revealed no lasting positive effects from either the leaflet or the movie. Our results suggest that both the movie and the leaflet are valued and effective intervention tools for improving knowledge about tick bites and strengthening self-efficacy and intentions to perform protective behavior against ticks and LD . Achieving lasting effects, however, calls for more action.

  2. Prediction of reversible perfusion defects by quantitative analysis of post-exercise electrocardiogram-gated acquisition of technetium-99m 2-methoxyisobutylisonitrile myocardial perfusion scintigraphy.

    PubMed

    Marcassa, C; Marzullo, P; Sambuceti, G; Parodi, O

    1992-01-01

    The aim of this study was to assess the reliability of the quantitative analysis of regional wall thickening with electrocardiographic-gated technetium-99m 2-methoxyisobutylisonitrile (SESTAMIBI) in predicting the reversibility of stress-induced perfusion defects. The assumption was that a preserved resting wall thickening in a segment with stress-induced perfusion defect would predict normal resting perfusion. Twenty-five patients with suspected coronary artery disease underwent planar stress-rest SESTAMIBI scintigraphy. The wall thickening was quantitatively evaluated as percentage increase in counts from diastole to systole; a ratio defined as the wall thickening index (WTI) between patient and normal profile (mean - 2 SD) below 1 was considered abnormal. Improvement of the perfusion pattern at rest was observed in 76% (54/71) of segments with a stress-induced perfusion defect; 90% of these segments had a (WTI) greater than 0.8. Five segments (9%) showed fixed perfusion defects despite a WTI value greater than 0.8. In conclusion, quantitative analysis of regional wall thickening by electrocardiographic-gated SESTAMIBI identifies segments with reversible perfusion defects; this may overcome the need for studies at rest and may direct the detection of hypoperfused but viable myocardium.

  3. Contrast enhanced MRI characterization of the perfusion territories fed by individual coronary arteries in ex-vivo porcine heart

    NASA Astrophysics Data System (ADS)

    Szeverenyi, Nikolaus M.; Searles, Bruce; Pertsov, Arkady

    2008-03-01

    Sudden cardiac death is often caused by ventricular arrhythmias. These arrhythmias are believed to originate from the border zones where tissue was damaged by an ischemic event involving the coronary arteries. The specific mechanisms relating the geometry of these territories to the electrical behavior remains poorly understood. A major problem is the lack of detailed information describing the morphology of the affected perfusion bed. We present the first perfusion MR images of excised whole heart preparations where the irregular boundaries of perfusion territories are described. The filling pattern and final volume of the RCA perfusion territory are clearly visualized.

  4. Total ellipse of the heart valve: the impact of eccentric stent distortion on the regional dynamic deformation of pericardial tissue leaflets of a transcatheter aortic valve replacement

    PubMed Central

    Gunning, Paul S.; Saikrishnan, Neelakantan; Yoganathan, Ajit P.; McNamara, Laoise M.

    2015-01-01

    Transcatheter aortic valve replacements (TAVRs) are a percutaneous alternative to surgical aortic valve replacements and are used to treat patients with aortic valve stenosis. This minimally invasive procedure relies on expansion of the TAVR stent to radially displace calcified aortic valve leaflets against the aortic root wall. However, these calcium deposits can impede the expansion of the device causing distortion of the valve stent and pericardial tissue leaflets. The objective of this study was to elucidate the impact of eccentric TAVR stent distortion on the dynamic deformation of the tissue leaflets of the prosthesis in vitro. Dual-camera stereophotogrammetry was used to measure the regional variation in strain in a leaflet of a TAVR deployed in nominal circular and eccentric (eccentricity index = 28%) orifices, representative of deployed TAVRs in vivo. It was observed that (i) eccentric stent distortion caused incorrect coaptation of the leaflets at peak diastole resulting in a ‘peel-back’ leaflet geometry that was not present in the circular valve and (ii) adverse bending of the leaflet, arising in the eccentric valve at peak diastole, caused significantly higher commissure strains compared with the circular valve in both normotensive and hypertensive pressure conditions (normotension: eccentric = 13.76 ± 2.04% versus circular = 11.77 ± 1.61%, p = 0.0014, hypertension: eccentric = 15.07 ± 1.13% versus circular = 13.56 ± 0.87%, p = 0.0042). This study reveals that eccentric distortion of a TAVR stent can have a considerable impact on dynamic leaflet deformation, inducing deleterious bending of the leaflet and increasing commissures strains, which might expedite leaflet structural failure compared to leaflets in a circular deployed valve. PMID:26674192

  5. Ex Vivo Lung Perfusion: Establishment and Operationalization in Iran.

    PubMed

    Shafaghi, Shadi; Abbasi Dezfuli, Azizollah; Ansari Aval, Zahra; Sheikhy, Kambiz; Farzanegan, Behrooz; Mortaz, Esmaeil; Emami, Habib; Aigner, Clemens; Hosseini-Baharanchi, Fatemeh Sadat; Najafizadeh, Katayoun

    2017-02-01

    Although the number of lung transplants is limited because of general shortage of organ donors, ex vivo lung perfusion is a novel method with 2 main benefits, including better evaluation of lung potential and recovery of injured lungs. The main aim of this study was to establish and operationalize ex vivo lung perfusion as the first experience in Iran. This was a prospective operational research study on 5 cases, including 1 pig from Vienna Medical University and 4 patients from Masih Daneshvari Hospital. All organ donations from brain dead donors were evaluated according to lung transplant or ex vivo lung perfusion criteria from May 2013 to July 2015 in Tehran, Iran. If a donor did not have any sign of severe chest trauma or pneumonia but had poor oxygenation due to possible atelectasis or neurogenic pulmonary edema, their lungs were included for ex vivo lung perfusion. A successful trend in the difference between the pulmonary arterial Po2 and the left atrial Po2 was observed, as well as an increasing pattern in other functional parameters, including dynamic lung compliance and a decreasing trend in pulmonary vascular resistance. These initial trials indicate that ex vivo lung perfusion can lead to remarkable progress in lung transplant in Iran. They also provide several important pieces of guidance for successful ex vivo lung perfusion, including the necessity of following standard lung retrieval procedures and monitoring temperature and pressure precisely. The development of novel methods can provide opportunities for further research studies on lungs of deceased donors and lead to undiscovered findings. By keeping this science up to date in Iran and developing such new and creative methods, we can reveal effective strategies to promote the quality of donor lungs to support patients on transplant wait lists.

  6. Perfusion decellularization of whole organs.

    PubMed

    Guyette, Jacques P; Gilpin, Sarah E; Charest, Jonathan M; Tapias, Luis F; Ren, Xi; Ott, Harald C

    2014-01-01

    The native extracellular matrix (ECM) outlines the architecture of organs and tissues. It provides a unique niche of composition and form, which serves as a foundational scaffold that supports organ-specific cell types and enables normal organ function. Here we describe a standard process for pressure-controlled perfusion decellularization of whole organs for generating acellular 3D scaffolds with preserved ECM protein content, architecture and perfusable vascular conduits. By applying antegrade perfusion of detergents and subsequent washes to arterial vasculature at low physiological pressures, successful decellularization of complex organs (i.e., hearts, lungs and kidneys) can be performed. By using appropriate modifications, pressure-controlled perfusion decellularization can be achieved in small-animal experimental models (rat organs, 4-5 d) and scaled to clinically relevant models (porcine and human organs, 12-14 d). Combining the unique structural and biochemical properties of native acellular scaffolds with subsequent recellularization techniques offers a novel platform for organ engineering and regeneration, for experimentation ex vivo and potential clinical application in vivo.

  7. Idiopathic pulmonary fibrosis. A rare cause of scintigraphic ventilation-perfusion mismatch

    SciTech Connect

    Pochis, W.T.; Krasnow, A.Z.; Collier, B.D.; Mewissen, M.W.; Almagro, U.A.; Hellman, R.S.; Isitman, A.T. )

    1990-05-01

    A case of idiopathic pulmonary fibrosis with multiple areas of mismatch on ventilation-perfusion lung imaging in the absence of pulmonary embolism is presented. Idiopathic pulmonary fibrosis is one of the few nonembolic diseases producing a pulmonary ventilation-perfusion mismatch. In this condition, chest radiographs may not detect the full extent of disease, and xenon-133 ventilation imaging may be relatively insensitive to morbid changes in small airways. Thus, when examining patients with idiopathic pulmonary fibrosis, one should be aware that abnormal perfusion imaging patterns without matching ventilation abnormalities are not always due to embolism. In this setting, contrast pulmonary angiography is often needed for accurate differential diagnosis.

  8. Mitral valve repair of isolated posterior leaflet prolapse: resect or respect?

    PubMed

    Tourmousoglou, Christos; Lalos, Spiros; Dougenis, Dimitrios

    2014-12-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether it is best in a patient with posterior leaflet prolapse to resect tissue from the posterior leaflet or to preserve the leaflet tissue by only adding neochordal reconstruction. Altogether, 279 papers were found using the reported search, of which 16 represented the best evidence to answer the clinical question. The authors, journal, date, country of publication, patient group, study type, relevant outcomes and results of these papers are tabulated. The results of the reported studies provided interesting results. All the studies identified were retrospective. Seven papers reported their results on mitral valve (MV) repair with neochordae. These papers included study groups of 74 to 662 patients. The spanned operation dates were from 1983 to 2008. The main disease was degenerative valve disease. The authors performed MV repair using neochordae with or without a ring. The 5-year freedom rate from reoperation was from 94.3 to 98.7%, the 10-year freedom rate from reoperation was from 81.7 to 94.7%, the 15-year freedom rate from reoperation was 92%, and the 18-year freedom rate from reoperation was 90.2%. The 5-year survival rate was from 96.6 to 96.9%, the 10-year survival rate was from 88 to 89.3%, the 15-year survival rate was 84%, and the 18-year survival rate was 66.8%. Seven papers reported their results on MV repair with resection techniques. These papers included patient groups of 162 to 3074 patients. Operation dates were from 1970 to 2008. The authors performed MV repair with quadrangular resection, plus or minus a sliding annuloplasty. The 5-year freedom rate from reoperation was from 93.9 to 98%, the 10-year freedom rate from reoperation was from 93 to 98.5%, and the 20-year freedom rate from reoperation was from 88 to 96.9%. The 5-year survival rate was from 86.9 to 96%, the 10-year survival rate was from 79 to 93.5%, the 15-year

  9. On the biomechanical role of glycosaminoglycans in the aortic heart valve leaflet.

    PubMed

    Eckert, Chad E; Fan, Rong; Mikulis, Brandon; Barron, Mathew; Carruthers, Christopher A; Friebe, Vincent M; Vyavahare, Naren R; Sacks, Michael S

    2013-01-01

    While the role of collagen and elastin fibrous components in heart valve valvular biomechanics has been extensively investigated, the biomechanical role of the glycosaminoglycan (GAG) gelatinous-like material phase remains unclear. In the present study, we investigated the biomechanical role of GAGs in porcine aortic valve (AV) leaflets under tension utilizing enzymatic removal. Tissue specimens were removed from the belly region of porcine AVs and subsequently treated with either an enzyme solution for GAG removal or a control (buffer with no enzyme) solution. A dual stress level test methodology was used to determine the effects at low and high (physiological) stress levels. In addition, planar biaxial tests were conducted both on-axis (i.e. aligned to the circumferential and radial axes) and at 45° off-axis to induce maximum shear, to explore the effects of augmented fiber rotations on the fiber-fiber interactions. Changes in hysteresis were used as the primary metric of GAG functional assessment. A simulation of the low-force experimental setup was also conducted to clarify the internal stress system and provide viscoelastic model parameters for this loading range. Results indicated that under planar tension the removal of GAGs had no measureable affect extensional mechanical properties (either on- or 45° off-axis), including peak stretch, hysteresis and creep. Interestingly, in the low-force range, hysteresis was markedly reduced, from 35.96±2.65% in control group to 25.00±1.64% (p<0.001) as a result of GAG removal. Collectively, these results suggest that GAGs do not play a direct role in modulating the time-dependent tensile properties of valvular tissues. Rather, they appear to be strongly connected with fiber-fiber and fiber-matrix interactions at low force levels. Thus, we speculate that GAGs may be important in providing a damping mechanism to reduce leaflet flutter when the leaflet is not under high tensile stress. Copyright © 2012 Acta Materialia

  10. On the Biomechanical Role of Glycosaminoglycans in the Aortic Heart Valve Leaflet

    PubMed Central

    Eckert, Chad E.; Fan, Rong; Mikulis, Brandon; Barron, Mathew; Carruthers, Christopher A.; Friebe, Vincent M.; Vyavahare, Naren R.; Sacks, Michael S.

    2012-01-01

    While the role of collagen and elastin fibrous components in heart valve valvular biomechanics has been extensively investigated [see Sacks et al. 2009 J. Biomech. 42, 1804-24], the biomechanical role of the glycosaminoglycan (GAG) gelatinous-like material phase remains unclear. In the present study, we investigated the biomechanical role of GAGs in porcine aortic valve (AV) leaflets under tension utilizing enzymatic removal. Tissue specimens were removed from the belly region of porcine AVs and subsequently treated with either an enzyme solution for GAG removal, or a control (buffer with no enzyme) solution. A dual stress level test methodology was used to determine the effects at low and high (physiological) stress levels). In addition, planar biaxial tests were conducted both on-axis (i.e. aligned to the circumferential and radial axes) and at 45° off-axis to induce maximum shear, to explore the effects of augmented fiber rotations on the fiber-fiber interactions. Changes in hysteresis were used as the primary metric of GAG functional assessment. A simulation of the low force experimental setup was also conducted to clarify the internal stress system and provide viscoelastic model parameters fo this loading range. Results indicated that under planar tension the removal of GAGs had no measureable affect extensional mechanical properties (either on- or 45° off-axis) including peak stretch, hysteresis, or creep. Interestingly, in the low force range, hysteresis was markedly reduced from 35.96 ± 2.65% in control group to 25.00 ± 1.64% (p < 0.001) as a result of GAG removal. Collectively, these results suggest that GAGs do not play a direct role in modulating the time-dependent tensile properties of valvular tissues. Rather, they appear to be strongly connected with fiber-fiber and fiber-matrix interactions at low forces levels. Thus, we speculate that GAGs may be important in providing a damping mechanism to reduce leaflet flutter when the leaflet is not under

  11. Thallium-201 myocardial perfusion imaging in myocarditis

    SciTech Connect

    Tamaki, N.; Yonekura, Y.; Kadota, K.; Kambara, H.; Torizuka, K.

    1985-08-01

    TI-201 myocardial perfusion imaging was performed in six patients with clinically documented myocarditis. Each case manifested electrocardiographic abnormalities with elevation of serum cardiac enzymes and no significant stenosis of the coronary arteries observed on angiogram. Resting TI-201 images were visually assessed by three observers. Focal perfusion defects were observed in three cases (50%), among which two showed multiple perfusion defects. Emission computed tomography using TI-201 clearly delineated multifocal lesions in the first case. On the other hand, no significant perfusion defects were noted in the remaining three cases. Thus, myocarditis should be considered as one of the disease entities that may produce perfusion defects on TI-201 myocardial imaging.

  12. Perfusion studies in cholera: methods and procedures.

    PubMed

    van Loon, F P; Gyr, K; Banik, A K

    1992-09-01

    This paper reviews the characteristics of perfusion techniques in the study of intestinal functions by specifically examining the methods and procedures of perfusion in patients with diarrhoea due to infection with V. cholerae 01. Because of abundant jejunal secretion of water and electrolytes in cholera, perfusion studies require special approaches with regard to patient preparation, use of tubing material, selection of markers, and rate of perfusion. A discussion on specific problems involved in marker perfusion techniques in cholera and on the interpretation of the results is followed by practical recommendations.

  13. Does machine perfusion decrease ischemia reperfusion injury?

    PubMed

    Bon, D; Delpech, P-O; Chatauret, N; Hauet, T; Badet, L; Barrou, B

    2014-06-01

    In 1990's, use of machine perfusion for organ preservation has been abandoned because of improvement of preservation solutions, efficient without perfusion, easy to use and cheaper. Since the last 15 years, a renewed interest for machine perfusion emerged based on studies performed on preclinical model and seems to make consensus in case of expanded criteria donors or deceased after cardiac death donations. We present relevant studies highlighted the efficiency of preservation with hypothermic machine perfusion compared to static cold storage. Machines for organ preservation being in constant evolution, we also summarized recent developments included direct oxygenation of the perfusat. Machine perfusion technology also enables organ reconditioning during the last hours of preservation through a short period of perfusion on hypothermia, subnormothermia or normothermia. We present significant or low advantages for machine perfusion against ischemia reperfusion injuries regarding at least one primary parameter: risk of DFG, organ function or graft survival.

  14. Color flow signal in the left atrium as a mirror image artifact suggesting one leaflet constriction of the St. Jude Medical valve: a case report.

    PubMed

    Iga, K; Izumi, C; Konishi, T

    2000-01-01

    Color Doppler echocardiography detected an abnormal color flow signal originating from the prosthetic mitral valve and extending to the left atrium during diastole in an 84-year-old woman with St. Jude Medical valve replacement. The flow was away from the transducer and almost identical to the left ventricular inflow signal except for the direction. Cinefluoroscopy showed one of the leaflets fixed at systole whereas the other leaflet was mobile. After reinforcement of anticoagulant therapy, this abnormal color flow signal disappeared and motion of both leaflets normalized. This color flow signal, presumably a mirror image artifact of the left ventricular inflow caused by the immobilized leaflet, could be a sign of one leaflet constriction in patients with St. Jude Medical valve replacement.

  15. Patient information leaflets: informing or frightening? A focus group study exploring patients' emotional reactions and subsequent behavior towards package leaflets of commonly prescribed medications in family practices.

    PubMed

    Herber, Oliver Rudolf; Gies, Verena; Schwappach, David; Thürmann, Petra; Wilm, Stefan

    2014-10-02

    The purpose of patient information leaflets (PILs) is to inform patients about the administration, precautions and potential side effects of their prescribed medication. Despite European Commission guidelines aiming at increasing readability and comprehension of PILs little is known about the potential risk information has on patients. This article explores patients' reactions and subsequent behavior towards risk information conveyed in PILs of commonly prescribed drugs by general practitioners (GPs) for the treatment of Type 2 diabetes, hypertension or hypercholesterolemia; the most frequent cause for consultations in family practices in Germany. We conducted six focus groups comprising 35 patients which were recruited in GP practices. Transcripts were read and coded for themes; categories were created by abstracting data and further refined into a coding framework. Three interrelated categories are presented: (i) The vast amount of side effects and drug interactions commonly described in PILs provoke various emotional reactions in patients which (ii) lead to specific patient behavior of which (iii) consulting the GP for assistance is among the most common. Findings show that current description of potential risk information caused feelings of fear and anxiety in the reader resulting in undesirable behavioral reactions. Future PILs need to convey potential risk information in a language that is less frightening while retaining the information content required to make informed decisions about the prescribed medication. Thus, during the production process greater emphasis needs to be placed on testing the degree of emotional arousal provoked in patients when reading risk information to allow them to undertake a benefit-risk-assessment of their medication that is based on rational rather than emotional (fearful) reactions.

  16. Effect of the mitral valve on diastolic flow patterns

    SciTech Connect

    Seo, Jung Hee; Vedula, Vijay; Mittal, Rajat; Abraham, Theodore; Dawoud, Fady; Luo, Hongchang; Lardo, Albert C.

    2014-12-15

    The leaflets of the mitral valve interact with the mitral jet and significantly impact diastolic flow patterns, but the effect of mitral valve morphology and kinematics on diastolic flow and its implications for left ventricular function have not been clearly delineated. In the present study, we employ computational hemodynamic simulations to understand the effect of mitral valve leaflets on diastolic flow. A computational model of the left ventricle is constructed based on a high-resolution contrast computed-tomography scan, and a physiological inspired model of the mitral valve leaflets is synthesized from morphological and echocardiographic data. Simulations are performed with a diode type valve model as well as the physiological mitral valve model in order to delineate the effect of mitral-valve leaflets on the intraventricular flow. The study suggests that a normal physiological mitral valve promotes the formation of a circulatory (or “looped”) flow pattern in the ventricle. The mitral valve leaflets also increase the strength of the apical flow, thereby enhancing apical washout and mixing of ventricular blood. The implications of these findings on ventricular function as well as ventricular flow models are discussed.

  17. High energy phosphate depletion in leaflet matrix cells during processing of cryopreserved cardiac valves.

    PubMed

    Messier, R H; Domkowski, P W; Aly, H M; Abd-Elfattah, A S; Crescenzo, D G; Wallace, R B; Hopkins, R A

    1992-05-01

    Preimplantation preparation of cardiac valves includes three major steps: (1) harvesting with accompanying ischemia (warm time from cessation of donor heart beat), (2) antibiotic disinfection, and (3) controlled-rate cryopreservation. To define the interdependent injury effects of these manipulations on leaflet matrix cells and specifically the potential for prolonged harvest-related ischemia to predispose greater injury by the subsequent steps, 96 semilunar valves were harvested from pigs in a manner analogous to human heart valve retrievals and randomly allocated to study groups as follows: 48 control valves were exposed to increasing harvested-related ischemic times, (2, 6, 12, 24 hr) and immersed in liquid nitrogen to arrest metabolic activity (i.e., prior to cryopreservation) and conclude the ischemia; another 48 were similarly harvested, subjected to identical ischemic times, then disinfected in 4 degrees C RPMI medium with standard antibiotics for 24 hr and dimethylsulfoxide cryopreserved at -1 degrees C/min to -170 degrees C (i.e., formal cryopreservation protocol). At thawing, each valve was extracted in 12% trichloroacetic acid and assayed by high performance liquid chromatography for components of the adenine nucleotide pool including ATP, lower energy nucleotides (total adenine nucleotides, [TAN] = [ATP] + [ADP] + [AMP]), adenosine, and the diffusible purines. Results are reported as nanomoles metabolite/milligram of leaflet cell protein (Lowry) and reflect a maintenance of total high energy phosphates in the control groups (5.41 +/- 0.29 nmole TAN at 2 hr; 8.34 +/- 0.67 nmole TAN at 24 hr), which fell significantly in all cryopreserved groups (1.27 +/- 0.33 nmole TAN at 2 hr; 0.34 +/- 0.22 nmole TAN at 24 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

  18. TIME DEPENDENT BIAXIAL MECHANICAL BEHAVIOR OF THE AORTIC HEART VALVE LEAFLET

    PubMed Central

    Stella, John A.; Liao, Jun; Sacks, Michael S.

    2007-01-01

    Despite continued progress in the treatment of aortic valve (AV) disease, current treatments continue to be challenged to consistently restore AV function for extended durations. Improved approaches toward AV repair and replacement rests upon our ability to more fully comprehend and simulate AV function. While the elastic behavior the AV leaflet (AVL) has been previously investigated, time dependent behaviors under physiological biaxial loading states have yet to be quantified. In the current study, we performed strain rate, creep, and stress relaxation experiments using porcine AVL under planar biaxial stretch and loaded to physiological levels (60 N/m equi-biaxial tension), with strain rates ranging from quasi-static to physiologic. The resulting stress-strain responses were found to be independent of strain rate, as was the observed low level of hysteresis (∼17%). Stress relaxation and creep results indicated that while the AVL exhibited significant stress relaxation, it exhibited negligible creep over the three hour test duration. These results are all in accordance with our previous findings for the mitral valve anterior leaflet (MVAL) (Grashow et al., 2006, ABME vol. 34, pp. 315-25; Grashow et al., ABME, Vol. 34, pp. 1509-18, 2006), and support our observations that valvular tissues are functionally anisotropic, quasi-elastic biological materials. These results appear to be unique to valvular tissues, and indicate an ability to withstand loading without time-dependent effects under physiologic loading conditions. Based on a recent study that suggested valvular collagen fibrils are not intrinsically viscoelastic (Liao, et al., JBME, vol. 129, 2007), we speculate that the mechanisms underlying this quasi-elastic behavior may be attributed to supra-fibrillar structure unique to valvular tissue. These mechanisms are an important functional aspect of native valvular tissues, and are likely critical to improve our understanding of valvular disease and help guide

  19. The influence of health literacy on comprehension of a colonoscopy preparation information leaflet

    PubMed Central

    Smith, Samuel G.; von Wagner, Christian; McGregor, Lesley M.; Curtis, Laura M.; Wilson, Elizabeth A. H.; Serper, Marina; Wolf, Michael S.

    2012-01-01

    BACKGROUND Successful bowel preparation is important for safe, efficacious, cost-effective colonoscopy procedures, however poor preparation is common. OBJECTIVE We sought to determine if there was an association between health literacy and comprehension of typical written instructions on how to prepare for a colonoscopy to enable more targeted interventions in this area. DESIGN Cross-sectional observational study SETTING Primary care clinics and federally qualified health centres in Chicago, Illinois. PATIENTS 764 participants (mean age: 63 years; Standard Deviation: 5.42) were recruited. The sample was from a mixed socio-demographic background and 71.9% of the participants were classified as having adequate health literacy scores. INTERVENTION 764 participants were presented with an information leaflet outlining the bowel preparatory instructions for colonoscopy. MAIN OUTCOME MEASURES Five questions assessing comprehension of the instructions in an ‘open book’ test. RESULTS Comprehension scores on the bowel preparation items were low. The mean number of items correctly answered was 3.2 (Standard Deviation, 1.2) out of a possible 5. Comprehensions scores overall and for each individual item differed significantly by health literacy level (all p<0.001). After controlling for gender, age, race, socio-economic status and previous colonoscopy experience in a multivariable model, health literacy was a significant predictor of comprehension (inadequate vs. adequate: β = −0.2; p < 0.001; marginal vs. adequate: β = −0.2; p < 0.001). LIMITATIONS The outcome represents a simulated task and not actual comprehension of preparation instructions for participants’ own recommended behavior. CONCLUSIONS Comprehension of a written colonoscopy preparation leaflet was generally low and significantly more so among people with low health literacy. Poor comprehension has implications for the safety and economic impact of gastroenterological procedures such as colonoscopy

  20. The impact of imperfect frame deployment and rotational orientation on stress within the prosthetic leaflets during transcatheter aortic valve implantation.

    PubMed

    Bailey, Jonathon; Curzen, Nick; Bressloff, Neil W

    2017-02-28

    TAVI devices are manufactured with cylindrical frames. However, the frames are rarely cylindrical post-deployment since deformation due to localised under expansion can be induced by calcified material on the native valve leaflets exerting irregular forces upon the frame. Consequently, the leaflets within a deformed TAVI device may undergo elevated stress during operation, which may lead to premature device failure. Using computational analysis a complete TAVI device model was simulated undergoing deployment into an aortic root model derived from CT data for a patient with severe calcific aortic stenosis, followed by a pressure simulated cardiac cycle. The complete analysis was performed eight times, each with the device at a different rotational orientation relative to the native valve, with an increment spacing of 15°. The TAVI device frames consistently featured significant distortions associated with bulky calcified material at the base of the non-coronary sinus. It was found that the average von Mises stress in the prosthetic valves was only increased in one of the cases relative to an idealised device. However, the maximum von Mises stress in the prosthetic valves was elevated in the majority of the cases. Furthermore, it was found that there were preferable orientations to deploy the prosthetic device, in this case, when the prosthetic leaflets were aligned with the native leaflets. As device orientation deviated from this orientation, the stresses in the valve increased because the distance between the prosthetic commissures decreased. This potentially could represent a sufficient increase in stress to induce variation in device lifespan.

  1. Birds, Bats, and Butterflies. A Leaflet for Adults Who Want To Share Nature with Children. No. 1-4.

    ERIC Educational Resources Information Center

    Baldwin, Mark K., Ed.

    This series of leaflets provides information about nature education in outdoor settings. Each issue begins with an account of a personal experience with children in nature. Following the personal narrative is a section titled, "A Nature Primer," which provides scientific information about a topic in nature. The next section, "Ready,…

  2. Microstructured Nickel-Titanium Thin Film Leaflets for Hybrid Tissue Engineered Heart Valves Fabricated by Magnetron Sputter Deposition.

    PubMed

    Loger, K; Engel, A; Haupt, J; Lima de Miranda, R; Lutter, G; Quandt, E

    2016-03-01

    Heart valves are constantly exposed to high dynamic loading and are prone to degeneration. Therefore, it is a challenge to develop a durable heart valve substitute. A promising approach in heart valve engineering is the development of hybrid scaffolds which are composed of a mechanically strong inorganic mesh enclosed by valvular tissue. In order to engineer an efficient, durable and very thin heart valve for transcatheter implantations, we developed a fabrication process for microstructured heart valve leaflets made from a nickel-titanium (NiTi) thin film shape memory alloy. To examine the capability of microstructured NiTi thin film as a matrix scaffold for tissue engineered hybrid heart valves, leaflets were successfully seeded with smooth muscle cells (SMCs). In vitro pulsatile hydrodynamic testing of the NiTi thin film valve leaflets demonstrated that the SMC layer significantly improved the diastolic sufficiency of the microstructured leaflets, without affecting the systolic efficiency. Compared to an established porcine reference valve model, magnetron sputtered NiTi thin film material demonstrated its suitability for hybrid tissue engineered heart valves.

  3. A Controlled Trial of the Knowledge Impact of Tuberculosis Information Leaflets among Staff Supporting Substance Misusers: Pilot Study

    PubMed Central

    Roy, Anjana; Abubakar, Ibrahim; Chapman, Ann; Andrews, Nick; Pattinson, Mike; Lipman, Marc; Rodrigues, Laura C.; Figueroa, Jose; Tamne, Surinder; Catchpole, Mike

    2011-01-01

    Background Information leaflets are widely used to increase awareness and knowledge of disease. Limited research has, to date, been undertaken to evaluate the efficacy of these information resources. This pilot study sought to determine whether information leaflets developed specifically for staff working with substance mis-users improved knowledge of tuberculosis (TB). Method Staffs working with individuals affected by substance mis-use were recruited between January and May 2008. All participants were subjectively allocated by their line manager either to receive the TB-specific leaflet or a control leaflet providing information on mental health. Level of knowledge of TB was assessed using questionnaires before and after the intervention and data analysed using McNemar's exact test for matched pairs. Results The control group showed no evidence of a change in knowledge of TB, whereas the TB questionnaire group demonstrated a significant increase in knowledge including TB being curable (81% correct before to 100% correct after), length of treatment required (42% before to 73% after), need to support direct observation (18% to 62%) and persistent fever being a symptom (56% to 87%). Among key workers, who have a central role in implementing a care plan, 88% reported never receiving any TB awareness-raising intervention prior to this study, despite 11% of all respondents having TB diagnosed among their clients. Conclusion Further randomized controlled trials are required to confirm the observed increase in short-term gain in knowledge and to investigate whether knowledge gain leads to change in health status. PMID:21698103

  4. Lipid asymmetry in plant plasma membranes: phosphate deficiency-induced phospholipid replacement is restricted to the cytosolic leaflet.

    PubMed

    Tjellström, Henrik; Hellgren, Lars I; Wieslander, Ake; Sandelius, Anna Stina

    2010-04-01

    As in other eukaryotes, plant plasma membranes contain sphingolipids, phospholipids, and free sterols. In addition, plant plasma membranes also contain sterol derivatives and usually <5 mol% of a galactolipid, digalactosyldiacylglycerol (DGDG). We earlier reported that compared to fully fertilized oats (Avena sativa), oats cultivated without phosphate replaced up to 70 mol% of the root plasma membrane phospholipids with DGDG. Here, we investigated the implications of a high DGDG content on membrane properties. The phospholipid-to-DGDG replacement almost exclusively occurred in the cytosolic leaflet, where DGDG constituted up to one-third of the lipids. In the apoplastic (exoplasmic) leaflet, as well as in rafts, phospholipids were not replaced by DGDG, but by acylated sterol glycosides. Liposome studies revealed that the chain ordering in free sterol/phospholipid mixtures clearly decreased when >5 mol% DGDG was included. As both the apoplastic plasma membrane leaflet (probably the major water permeability barrier) and rafts both contain only trace amounts of DGDG, we conclude that this lipid class is not compatible with membrane functions requiring a high degree of lipid order. By not replacing phospholipids site specifically with DGDG, negative functional effects of this lipid in the plasma membrane are avoided.-Tjellström, H., Hellgren, L. I., Wieslander, A., Sandelius, A. S. Lipid asymmetry in plant plasma membranes: phosphate deficiency-induced phospholipid replacement is restricted to the cytosolic leaflet.

  5. Quantitative histologic analysis of the mitral valve anterior leaflet: ischemic alterations and implications for valve replacement design

    NASA Astrophysics Data System (ADS)

    Quick, David W.; Kunzelman, Karyn S.; Cochran, Richard P.

    1999-06-01

    There is a current trend to design innovative mitral valve replacements that mimic the native mitral valve (MV). A prerequisite for these new designs is the characterization of MV structure. This study was conducted to determine the distribution of MV collagen and glycosaminoglycan (GAGs) in MV anterior leaflets. Methods: Specimens from the mid-line of eight sheep MV anterior leaflets were stained with aniline blue (collagen) and alcian blue (GAGs). These specimens were analyzed using an image analysis system running Optimas software. Based on the luminance of stains within individual valve layers, the distribution of valvular collagen and GAGs from leaflet annulus to free-edge were determined. Results: Near the annulus, 100% of MV thickness is fibrosa (collagen dominated layer). Moving towards the free-edge, fibrosa prominence decreases and there is a transition to spongiosa (GAG dominated layer). Near the free-edge 100% of MV thickness is dominated by the spongiosa. Conclusions: Valvular collagen dominates MV structure near the annulus to support the stresses of bending and pressurization. Valvular GAGs dominate the MV near the free-edge to absorb the impact of leaflet coaptation. Image analysis has proven to be an effective tool to evaluate MV structure and facilitate the design of valve replacements.

  6. Epicardially-derived Fibroblasts Preferentially Contribute to the Parietal Leaflets of the Atrioventricular Valves in the Murine Heart

    PubMed Central

    Wessels, Andy; van den Hoff, Maurice J. B.; Adamo, Richard F.; Phelps, Aimee L.; Lockhart, Marie M.; Sauls, Kimberly; Briggs, Laura E.; Norris, Russell A.; van Wijk, Bram; Perez-Pomares, Jose M.; Dettman, Robert W.; Burch, John B. E.

    2012-01-01

    The importance of the epicardium for myocardial and valvuloseptal development has been well established; perturbation of epicardial development results in cardiac abnormalities, including thinning of the ventricular myocardial wall and malformations of the atrioventricular valvuloseptal complex. To determine the spatiotemporal contribution of epicardially derived cells to the developing fibroblast population in the heart we have used a mWt1/IRES/GFP-Cre mouse to trace the fate of EPDCs from embryonic day (ED)10 until birth. EPDCs begin to populate the compact ventricular myocardium around ED12. The migration of epicardially-derived fibroblasts toward the interface between compact and trabecular myocardium is completed around ED14. Remarkably, epicardially-derived fibroblasts do not migrate into the trabecular myocardium until after ED17. Migration of EPDCs into the atrioventricular cushion mesenchyme commences around ED12. As development progresses, the number of EPDCs increases significantly, specifically in the leaflets which derive from the lateral atrioventricular cushions. In these developing leaflets the epicardially-derived fibroblasts eventually largely replace the endocardially-derived cells. Importantly, the contribution of EPDCs to the leaflets derived from the major AV cushions is very limited. The differential contribution of EPDCs to the various leaflets of the atrioventricular valves provides a new paradigm in valve development and could lead to new insights into the pathogenesis of abnormalities that preferentially affect individual components of this region of the heart. The notion that there is a significant difference in the contribution of epicardially and endocardially derived cells to the individual leaflets of the atrioventricular valves has also important pragmatic consequences for the use of endocardial and epicardial cre-mouse models in studies of heart development. PMID:22546693

  7. Intestinal perfusion monitoring using photoplethysmography

    NASA Astrophysics Data System (ADS)

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. Nance; Coté, Gerard L.

    2013-08-01

    In abdominal trauma patients, monitoring intestinal perfusion and oxygen consumption is essential during the resuscitation period. Photoplethysmography is an optical technique potentially capable of monitoring these changes in real time to provide the medical staff with a timely and quantitative measure of the adequacy of resuscitation. The challenges for using optical techniques in monitoring hemodynamics in intestinal tissue are discussed, and the solutions to these challenges are presented using a combination of Monte Carlo modeling and theoretical analysis of light propagation in tissue. In particular, it is shown that by using visible wavelengths (i.e., 470 and 525 nm), the perfusion signal is enhanced and the background contribution is decreased compared with using traditional near-infrared wavelengths leading to an order of magnitude enhancement in the signal-to-background ratio. It was further shown that, using the visible wavelengths, similar sensitivity to oxygenation changes could be obtained (over 50% compared with that of near-infrared wavelengths). This is mainly due to the increased contrast between tissue and blood in that spectral region and the confinement of the photons to the thickness of the small intestine. Moreover, the modeling results show that the source to detector separation should be limited to roughly 6 mm while using traditional near-infrared light, with a few centimeters source to detector separation leads to poor signal-to-background ratio. Finally, a visible wavelength system is tested in an in vivo porcine study, and the possibility of monitoring intestinal perfusion changes is showed.

  8. Crossed cerebellar diaschisis in patients with acute middle cerebral artery infarction: Occurrence and perfusion characteristics

    PubMed Central

    Sommer, Wieland H; Bollwein, Christine; Thierfelder, Kolja M; Baumann, Alena; Janssen, Hendrik; Ertl-Wagner, Birgit; Reiser, Maximilian F; Plate, Annika; Straube, Andreas

    2015-01-01

    We aimed to investigate the overall prevalence and possible factors influencing the occurrence of crossed cerebellar diaschisis after acute middle cerebral artery infarction using whole-brain CT perfusion. A total of 156 patients with unilateral hypoperfusion of the middle cerebral artery territory formed the study cohort; 352 patients without hypoperfusion served as controls. We performed blinded reading of different perfusion maps for the presence of crossed cerebellar diaschisis and determined the relative supratentorial and cerebellar perfusion reduction. Moreover, imaging patterns (location and volume of hypoperfusion) and clinical factors (age, sex, time from symptom onset) resulting in crossed cerebellar diaschisis were analysed. Crossed cerebellar diaschisis was detected in 35.3% of the patients with middle cerebral artery infarction. Crossed cerebellar diaschisis was significantly associated with hypoperfusion involving the left hemisphere, the frontal lobe and the thalamus. The degree of the relative supratentorial perfusion reduction was significantly more pronounced in crossed cerebellar diaschisis-positive patients but did not correlate with the relative cerebellar perfusion reduction. Our data suggest that (i) crossed cerebellar diaschisis is a common feature after middle cerebral artery infarction which can robustly be detected using whole-brain CT perfusion, (ii) its occurrence is influenced by location and degree of the supratentorial perfusion reduction rather than infarct volume (iii) other clinical factors (age, sex and time from symptom onset) did not affect the occurrence of crossed cerebellar diaschisis. PMID:26661242

  9. Crossed cerebellar diaschisis in patients with acute middle cerebral artery infarction: Occurrence and perfusion characteristics.

    PubMed

    Sommer, Wieland H; Bollwein, Christine; Thierfelder, Kolja M; Baumann, Alena; Janssen, Hendrik; Ertl-Wagner, Birgit; Reiser, Maximilian F; Plate, Annika; Straube, Andreas; von Baumgarten, Louisa

    2016-04-01

    We aimed to investigate the overall prevalence and possible factors influencing the occurrence of crossed cerebellar diaschisis after acute middle cerebral artery infarction using whole-brain CT perfusion. A total of 156 patients with unilateral hypoperfusion of the middle cerebral artery territory formed the study cohort; 352 patients without hypoperfusion served as controls. We performed blinded reading of different perfusion maps for the presence of crossed cerebellar diaschisis and determined the relative supratentorial and cerebellar perfusion reduction. Moreover, imaging patterns (location and volume of hypoperfusion) and clinical factors (age, sex, time from symptom onset) resulting in crossed cerebellar diaschisis were analysed. Crossed cerebellar diaschisis was detected in 35.3% of the patients with middle cerebral artery infarction. Crossed cerebellar diaschisis was significantly associated with hypoperfusion involving the left hemisphere, the frontal lobe and the thalamus. The degree of the relative supratentorial perfusion reduction was significantly more pronounced in crossed cerebellar diaschisis-positive patients but did not correlate with the relative cerebellar perfusion reduction. Our data suggest that (i) crossed cerebellar diaschisis is a common feature after middle cerebral artery infarction which can robustly be detected using whole-brain CT perfusion, (ii) its occurrence is influenced by location and degree of the supratentorial perfusion reduction rather than infarct volume (iii) other clinical factors (age, sex and time from symptom onset) did not affect the occurrence of crossed cerebellar diaschisis. © The Author(s) 2015.

  10. DiI Perfusion as a Method for Vascular Visualization in Ambystoma mexicanum.

    PubMed

    Saltman, Anna J; Barakat, May; Bryant, Donald M; Brodovskaya, Anastasia; Whited, Jessica L

    2017-06-16

    Perfusion techniques have been used for centuries to visualize the circulation of tissues. Axolotl (Ambystoma mexicanum) is a species of salamander that has emerged as an essential model for regeneration studies. Little is known about how revascularization occurs in the context of regeneration in these animals. Here we report a simple method for visualization of the vasculature in axolotl via perfusion of 1,1'-Dioctadecy-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI). DiI is a lipophilic carbocyanine dye that inserts into the plasma membrane of endothelial cells instantaneously. Perfusion is done using a peristaltic pump such that DiI enters the circulation through the aorta. During perfusion, dye flows through the axolotl's blood vessels and incorporates into the lipid bilayer of vascular endothelial cells upon contact. The perfusion procedure takes approximately one hour for an eight-inch axolotl. Immediately after perfusion with DiI, the axolotl can be visualized with a confocal fluorescent microscope. The DiI emits light in the red-orange range when excited with a green fluorescent filter. This DiI perfusion procedure can be used to visualize the vascular structure of axolotls or to demonstrate patterns of revascularization in regenerating tissues.

  11. Cerebral perfusion alterations in epileptic patients during peri-ictal and post-ictal phase: PASL vs DSC-MRI.

    PubMed

    Pizzini, Francesca B; Farace, Paolo; Manganotti, Paolo; Zoccatelli, Giada; Bongiovanni, Luigi G; Golay, Xavier; Beltramello, Alberto; Osculati, Antonio; Bertini, Giuseppe; Fabene, Paolo F

    2013-07-01

    Non-invasive pulsed arterial spin labeling (PASL) MRI is a method to study brain perfusion that does not require the administration of a contrast agent, which makes it a valuable diagnostic tool as it reduces cost and side effects. The purpose of the present study was to establish the viability of PASL as an alternative to dynamic susceptibility contrast (DSC-MRI) and other perfusion imaging methods in characterizing changes in perfusion patterns caused by seizures in epileptic patients. We evaluated 19 patients with PASL. Of these, the 9 affected by high-frequency seizures were observed during the peri-ictal period (within 5hours since the last seizure), while the 10 patients affected by low-frequency seizures were observed in the post-ictal period. For comparison, 17/19 patients were also evaluated with DSC-MRI and CBF/CBV. PASL imaging showed focal vascular changes, which allowed the classification of patients in three categories: 8 patients characterized by increased perfusion, 4 patients with normal perfusion and 7 patients with decreased perfusion. PASL perfusion imaging findings were comparable to those obtained by DSC-MRI. Since PASL is a) sensitive to vascular alterations induced by epileptic seizures, b) comparable to DSC-MRI for detecting perfusion asymmetries, c) potentially capable of detecting time-related perfusion changes, it can be recommended for repeated evaluations, to identify the epileptic focus, and in follow-up and/or therapy-response assessment.

  12. Quantitative pixelwise myocardial perfusion maps from first-pass perfusion MRI.

    PubMed

    Weng, A M; Ritter, C O; Beer, M; Hahn, D; Köstler, H

    2014-07-01

    To calculate and evaluate absolute quantitative myocardial perfusion maps from rest first-pass perfusion MRI. 10 patients after revascularization of myocardial infarction underwent cardiac rest first-pass perfusion MRI. Additionally, perfusion examinations were performed in 12 healthy volunteers. Quantitative myocardial perfusion maps were calculated by using a deconvolution technique, and results were compared were the findings of a sector-based quantification. Maps were typically calculated within 3 min per slice. For the volunteers, myocardial blood flow values of the maps were 0.51 ± 0.16 ml g(-1) per minute, whereas sector-based evaluation delivered 0.52 ± 0.15 ml g(-1) per minute. A t-test revealed no statistical difference between the two sets of values. For the patients, all perfusion defects visually detected in the dynamic perfusion series could be correctly reproduced in the maps. Calculation of quantitative perfusion maps from myocardial perfusion MRI examinations is feasible. The absolute quantitative maps provide additional information on the transmurality of perfusion defects compared with the visual evaluation of the perfusion series and offer a convenient way to present perfusion MRI findings. Voxelwise analysis of myocardial perfusion helps clinicians to assess the degree of tissue damage, and the resulting maps are a good tool to present findings to patients.

  13. Computed tomography perfusion imaging in spectacular shrinking deficit.

    PubMed

    Lee, Vivien H; John, Sayona; Mohammad, Yousef; Prabhakaran, Shyam

    2012-02-01

    Spectacular shrinking deficit (SSD) is characterized by abrupt onset of a major hemispheric stroke syndrome, followed by dramatic and rapid improvement. We retrospectively identified patients with SSD diagnosed at our institution between December 1, 2007, and June 30, 2009. We reviewed computed tomography perfusion (CTP) imaging to determine perfusion defect as a measure of initial ischemic penumbra, and magnetic resonance imaging diffusion-weighted imaging (DWI) to determine the final infarct core. Among the 472 consecutive ischemic stroke patients, 126 (27%) presented with major hemispheric ischemic stroke syndrome, defined as National Institutes of Health Stroke Scale score (NIHSS) ≥8 in the territory of the middle cerebral artery (MCA) or internal carotid artery (ICA). Out of these patients, we identified 8 SSD patients with available CTP data. In these 8 patients, the mean time to dramatic recovery was 3.4 hours (range, 0.75-7 hours), and the mean time from onset to CTP was 12.7 hours (range, 3-30 hours). All 8 patients had perfusion abnormalities in portions of the MCA territory (partial MCA territory in 5 patients and complete MCA territory in 3 patients). The mean time from onset to MRI DWI was 15.5 hours (range, 7.9-34 hours). Restricted diffusion was present in all patients in the corresponding MCA distribution. Vascular imaging revealed MCA occlusion in 2 patients. Cervical vascular imaging revealed carotid occlusion in 2 patients and high-grade carotid stenosis in 2 patients. The stroke mechanisms were cardioembolism in 2 patients, large artery in 4 patients, and unknown in 2 patients. Four patients had repeat CTP imaging available that demonstrated eventual resolution of the perfusion defect. SSD is associated with a "shrinking" clinical syndrome and a "shrinking" perfusion pattern on CTP that lags behind clinical recovery. CTP imaging corroborates that a larger territory is at risk in SSD and contributes to better understanding of SSD.

  14. Ultrasound perfusion signal processing for tumor detection

    NASA Astrophysics Data System (ADS)

    Kim, MinWoo; Abbey, Craig K.; Insana, Michael F.

    2016-04-01

    Enhanced blood perfusion in a tissue mass is an indication of neo-vascularity and a sign of a potential malignancy. Ultrasonic pulsed-Doppler imaging is a preferred modality for noninvasive monitoring of blood flow. However, the weak blood echoes and disorganized slow flow make it difficult to detect perfusion using standard methods without the expense and risk of contrast enhancement. Our research measures the efficiency of conventional power-Doppler (PD) methods at discriminating flow states by comparing measurement performance to that of an ideal discriminator. ROC analysis applied to the experimental results shows that power Doppler methods are just 30-50 % efficient at perfusion flows less than 1ml/min, suggesting an opportunity to improve perfusion assessment through signal processing. A new perfusion estimator is proposed by extending the statistical discriminator approach. We show that 2-D perfusion color imaging may be enhanced using this approach.

  15. Identification of cerebral perfusion using arterial spin labeling in patients with seizures in acute settings

    PubMed Central

    Yoo, Roh-Eul; Yoon, Byung-Woo; Lee, Sang Kun; Lee, Soon-Tae; Kang, Koung Mi; Choi, Seung Hong; Kim, Ji-hoon; Sohn, Chul-Ho; Park, Sun-Won; Han, Moon Hee

    2017-01-01

    This study aimed to explore the utility of arterial spin labeling perfusion-weighted imaging (ASL-PWI) in patients with suspected seizures in acute settings. A total of 164 patients who underwent ASL-PWI for suspected seizures in acute settings (with final diagnoses of seizure [n = 129], poststroke seizure [n = 18], and seizure mimickers [n = 17]), were included in this retrospective study. Perfusion abnormality was analyzed for: (1) pattern, (2) multifocality, and (3) atypical distribution against vascular territories. Perfusion abnormality was detected in 39% (50/129) of the seizure patients, most (94%, 47/50) being the hyperperfusion pattern. Of the patients with perfusion abnormality, multifocality or hemispheric involvement and atypical distribution against vascular territory were revealed in 46% (23/50) and 98% (49/50), respectively. In addition, seizures showed characteristic features including hyperperfusion (with or without non-territorial distribution) on ASL-PWI, thus differentiating them from poststroke seizures or seizure mimickers. In patients in whom seizure focus could be localized on both EEG and ASL-PWI, the concordance rate was 77%. The present study demonstrates that ASL-PWI can provide information regarding cerebral perfusion status in patients with seizures in acute settings and has the potential to be used as a non-invasive imaging tool to identify the cerebral perfusion in patients with seizures. PMID:28291816

  16. Framework for cognitive analysis of dynamic perfusion computed tomography with visualization of large volumetric data

    NASA Astrophysics Data System (ADS)

    Hachaj, Tomasz; Ogiela, Marek R.

    2012-10-01

    The proposed framework for cognitive analysis of perfusion computed tomography images is a fusion of image processing, pattern recognition, and image analysis procedures. The output data of the algorithm consists of: regions of perfusion abnormalities, anatomy atlas description of brain tissues, measures of perfusion parameters, and prognosis for infracted tissues. That information is superimposed onto volumetric computed tomography data and displayed to radiologists. Our rendering algorithm enables rendering large volumes on off-the-shelf hardware. This portability of rendering solution is very important because our framework can be run without using expensive dedicated hardware. The other important factors are theoretically unlimited size of rendered volume and possibility of trading of image quality for rendering speed. Such rendered, high quality visualizations may be further used for intelligent brain perfusion abnormality identification, and computer aided-diagnosis of selected types of pathologies.

  17. Dynamic perfusion assessment during perforator flap surgery: an up-to-date

    PubMed Central

    MUNTEAN, MAXIMILIAN VLAD; MUNTEAN, VALENTIN; ARDELEAN, FILIP; GEORGESCU, ALEXANDRU

    2015-01-01

    Flap monitoring technology has progressed alongside flap design. The highly variable vascular anatomy and the complexity associated with modern perforator flaps demands dynamic, real-time, intraoperative information about the vessel location, perfusion patterns and flap physiology. Although most surgeons still assess flap perfusion and viability based solely on clinical experience, studies have shown that results may be highly variable and often misleading. Poor judgment of intraoperative perfusion leads to major complications. Employing dynamic perfusion imaging during flap reconstruction has led to a reduced complication rate, lower morbidity, shorter hospital stay, and an overall better result. With the emergence of multiple systems capable of intraoperative flap evaluation, the purpose of this article is to review the two systems that have been widely accepted and are currently used by plastic surgeons: Indocyanine green angiography (ICGA) and dynamic infrared thermography (DIRT). PMID:26609259

  18. Particle image velocimetry study of pulsatile flow in bi-leaflet mechanical heart valves with image compensation method.

    PubMed

    Shi, Yubing; Yeo, Tony Joon Hock; Zhao, Yong; Hwang, Ned H C

    2006-12-01

    Particle Image Velocimetry (PIV) is an important technique in studying blood flow in heart valves. Previous PIV studies of flow around prosthetic heart valves had different research concentrations, and thus never provided the physical flow field pictures in a complete heart cycle, which compromised their pertinence for a better understanding of the valvular mechanism. In this study, a digital PIV (DPIV) investigation was carried out with improved accuracy, to analyse the pulsatile flow field around the bi-leaflet mechanical heart valve (MHV) in a complete heart cycle. For this purpose a pulsatile flow test rig was constructed to provide the necessary in vitro test environment, and the flow field around a St. Jude size 29 bi-leaflet MHV and a similar MHV model were studied under a simulated physiological pressure waveform with flow rate of 5.2 l/min and pulse rate at 72 beats/min. A phase-locking method was applied to gate the dynamic process of valve leaflet motions. A special image-processing program was applied to eliminate optical distortion caused by the difference in refractive indexes between the blood analogue fluid and the test section. Results clearly showed that, due to the presence of the two leaflets, the valvular flow conduit was partitioned into three flow channels. In the opening process, flow in the two side channels was first to develop under the presence of the forward pressure gradient. The flow in the central channel was developed much later at about the mid-stage of the opening process. Forward flows in all three channels were observed at the late stage of the opening process. At the early closing process, a backward flow developed first in the central channel. Under the influence of the reverse pressure gradient, the flow in the central channel first appeared to be disturbed, which was then transformed into backward flow. The backward flow in the central channel was found to be the main driving factor for the leaflet rotation in the valve

  19. Calcium acetate induces calcium uptake and formation of calcium-oxalate crystals in isolated leaflets of Gleditsia triacanthos L.

    PubMed

    Borchert, R

    1986-09-01

    During treatment of isolated, peeled leaflets of Gleditsia triacanthos with 0.5-2 mM [(45)Ca]acetate, saturation of the cell-wall free space with Ca(2+) occurred within 10 min and was followed by a period of 6-10 h during which there was no significant Ca-uptake into the protoplast, but apoplastic Ca(2+) was periodically released into the medium. Later, Ca(2+) was absorbed for 3-4 d at rates of up to 2.2 μmol Ca(2+)·h(-1)·(g FW)(-1) to final concentrations of 350 μmol Ca(2+)· (g FW)(-1). The distribution of absorbed Ca(2+) between cell wall, vacuole and Ca-oxalate crystals was determined during Ca-uptake. Wheras intact, cut leaflets deposited absorbed Ca(2+) as Ca-oxalate in the crystal cells, peeled leaflets lacking crystal cells accumulated at least 40-50 μmol·(g FW)(-1) soluble Ca(2+) before the absorbed Ca(2+) was precipitated as Ca-oxalate. These observations indicate that the mechanisms for the continuous uptake of Ca(2+), the synthesis of oxalate and the precipitation of Ca(2+) as Ca-oxalate are operational in the crystal cells of intact leaflets, but not in the mesophyll cells of peeled leaflets where they must be induced by exposure to Ca(2+). The precipitation of absorbed Ca(2+) as Ca-oxalate by the crystal cells of isolated Gleditsia leaflets illustrates the role of these cells in the excretion of surplus Ca(2+) which enters normal, attached leaves with the transpiration stream.In addition to acetate, only Ca-lactate and Ca-carbonate lead to Ca-uptake, but at rates well below those observed with Ca-acetate. Other small organic anions (citrate, glycolate, glyoxalate, malate) and inorganic anions (chloride, nitrate, sulfate) did not permit Ca-uptake. Acetate-(14)C was rapidly absorbed during Ca-uptake, but less than 20% was incorporated into Ca-oxalate; the rest remained mostly in the soluble fraction or was metabolized to CO2. Acetate, as a permeable weak acid, may enable rapid Ca-uptake by stimulating proton extrusion at the plasmalemma and by

  20. Importance of anterior leaflet tethering in predicting recurrence of ischemic mitral regurgitation after restrictive annuloplasty.

    PubMed

    van Garsse, Leen; Gelsomino, Sandro; Lucà, Fabiana; Lorusso, Roberto; Rao, Carmelo Massimiliano; Stefàno, Pieluigi; Maessen, Jos

    2012-04-01

    We investigated the relationship between anterior mitral leaflet (AML) tethering and recurrent ischemic mitral regurgitation (MR) after restrictive annuloplasty. We also explored whether the effect of AML tethering was secondary to modifications in left ventricular size and geometry. The study population consisted of 435 consecutive patients with chronic ischemic MR who survived combined coronary artery bypass grafting and undersized mitral ring annuloplasty performed at 3 institutions (University Hospital, Maastricht, The Netherlands; Careggi Hospital, Florence, Italy; and Civic Hospital, Brescia, Italy) from 2001 to 2008. The median follow-up was 44.7 months (interquartile range 25.9-66.4). The patients were divided by the baseline measurements into quintiles of AML tethering angle α' as follows: group 1, normal/slight AML tethering; group 2, mild AML tethering; group 3, moderate AML tethering; group 4, moderate-to-severe AML tethering; and group 5, severe AML tethering. Recurrence of MR was significantly greater in patients with moderate-to-severe (28.3%) and severe (39.4%) AML tethering (P < .001). A strong correlation was found between α' (r = 0.83, P < .001) and recurrent MR but a weak correlation with the posterior mitral angle β' (r = 0.12, P = .05). On logistic regression analysis corrected for other echocardiographic risk factors, moderate-severe AML tethering or worse (adjusted odds ratio, 3.6; 95% confidence interval, 3.0-4.1; P < .001) was a strong predictor of MR recurrence. Compared with patients with β' of 45 or greater, those with severe and moderate-severe AML tethering had more than 3.7 and 1.7 times greater odds of MR recurrence, respectively. No significant interactions were found between α' and the indexes of left ventricular function and geometry. Preoperative moderate-severe AML tethering or worse was strongly associated with MR recurrence. Thus, assessment of leaflet tethering should be incorporated into clinical risk assessment and

  1. How to Test Mandatory Text Templates: The European Patient Information Leaflet

    PubMed Central

    Pander Maat, Henk; Lentz, Leo; Raynor, David K.

    2015-01-01

    The structure of patient information leaflets (PILs) supplied with medicines in the European Union is largely determined by a regulatory template, requiring a fixed sequence of pre-formulated headings and sub-headings. The template has been criticized on various occasions, but it has never been tested with users. This paper proposes an alternative template, informed by templates used in the USA and Australia, and by previous user testing.The main research question is whether the revision better enables users to find relevant information. Besides, the paper proposes a methodology for testing templates. Testing document templates is complex, as they are “empty”. For both the current and the alternative template, we produced a document with bogus text and real headings (reflecting the empty template) and a real-life document with readable text (reflecting the “filled” template). The documents were tested both in Dutch and in English, with 64 British and 64 Dutch users. The test used a set of scenario questions that covers the full range of template (sub)topics; users needed to indicate the text locations where they expected each question to be answered. The revised template improved findability of information; this effect was strongest for the “filled” template with readable text. When participants were shown both filled templates, there was a clear preference for the revised template. A closer analysis of the findability data revealed question-specific effects of topic grouping, topic ordering, subtopic granularity and wording of headings. Most of these favoured the revised template, but our revision led to adverse effects as well, for instance in the new heading Check with your doctor. Language-specific effects showed that the wording of the headings is a delicate task. Generally, we conclude that document template designs can be analyzed in terms of the four parameters grouping, ordering, granularity and wording. Furthermore, they need to be tested on

  2. Three patients with signs of acute flail mitral leaflet seen on emergency department echo: a critical constellation within the focused cardiac exam.

    PubMed

    Bomann, J Scott; Stephenson, George; Wallace, Craig; Mao, Pras; Moore, Chris

    2014-05-01

    Acute flail mitral leaflet is a time-sensitive, reversible cause of cardiogenic shock. Transthoracic echocardiography (echo) is increasingly becoming a vital tool for non-cardiologist physicians who treat patients with undifferentiated chest pain and dyspnoea. The sonographic abnormalities seen in acute flail mitral leaflet are within the boundaries of a focused echo. Individually, these findings are non-specific. As a constellation, however, they are highly suggestive of this disease process. We present a case series of three patients with acute flail mitral leaflet seen on emergency department echo along with a discussion of the findings and the disease itself.

  3. Three patients with signs of acute flail mitral leaflet seen on emergency department echo: a critical constellation within the focused cardiac exam

    PubMed Central

    Stephenson, George; Wallace, Craig; Mao, Pras; Moore, Chris

    2015-01-01

    Abstract Acute flail mitral leaflet is a time‐sensitive, reversible cause of cardiogenic shock. Transthoracic echocardiography (echo) is increasingly becoming a vital tool for non‐cardiologist physicians who treat patients with undifferentiated chest pain and dyspnoea. The sonographic abnormalities seen in acute flail mitral leaflet are within the boundaries of a focused echo. Individually, these findings are non‐specific. As a constellation, however, they are highly suggestive of this disease process. We present a case series of three patients with acute flail mitral leaflet seen on emergency department echo along with a discussion of the findings and the disease itself. PMID:28191212

  4. AN UNUSUAL ECHOCARDIOGRAPHIC PATTERN OF A LEFT ATRIAL MYXOMA

    PubMed Central

    Mathurin, Jean-Robert; Adyanthaya, Ajit V.; Petrovich, Lawrence J.; Franco, Mauricio; Mattox, Kenneth L.; Alexander, James K.

    1977-01-01

    Unusual echocardiographic findings in a 58-year-old woman with a history of rheumatic fever and an angiographically demonstrated prolapsing left atrial myxoma are presented. With variations of gain and damping controls, it was possible to isolate a more distinct anterior mitral leaflet echo, or a more posterior linear echo, thought to represent the prolapsing tumor. The tumor, instead of presenting as a cloud of echoes behind the anterior mitral valve leaflet, demonstrated an alternate pattern of a single linear dense echo at this location. Echocardiography, though very useful in the diagnosis of left atrial tumors, can be fallible at times. Images PMID:15216092

  5. Improving patient information leaflets: developing and applying an evaluative model of patient-centredness for text.

    PubMed

    Fage-Butler, Antoinette

    2013-01-01

    The purpose of this paper is to present an evaluative model of patient-centredness for text and to illustrate how this can be applied to patient information leaflets (PILs) that accompany medication in the European Union. Patients have criticized PILs for sidelining their experiences, knowledge and affective needs, and denying their individuality. The health communication paradigm of patient-centredness provides valuable purchase on these issues, taking its starting point in the dignity and integrity of the patient as a person. Employing this evaluative model involves two stages. First, a Foucauldian Discourse Analysis is performed of sender and receiver and of the main discourses in PILs. These aspects are then evaluated using the perspectives of patient-centredness theory relating to the medical practitioner, patient and content. The evaluative model is illustrated via a PIL for medication for depression and panic attacks. Evaluation reveals a preponderance of biomedical statements, with a cluster of patient-centred statements primarily relating to the construction of the patient. The paper contributes a new method and evaluative approach to PIL and qualitative health research, as well as outlining a method that facilitates the investigation of interdiscursivity, a recent focus of critical genre analysis.

  6. Ciprofloxacin adsorption from aqueous solution onto chemically prepared carbon from date palm leaflets.

    PubMed

    El-Shafey, El-Said Ibrahim; Al-Lawati, Haider; Al-Sumri, Asmaa Soliman

    2012-01-01

    A chemically prepared carbon was synthesized from date palm leaflets via sulphuric acid carbonization at 160 degrees C. Adsorption of ciprofloxacin (CIP) from aqueous solution was investigated in terms of time, pH, concentration, temperature and adsorbent status (wet and dry). The equilibrium time was found to be 48 hr. The adsorption rate was enhanced by raising the temperature for both adsorbents, with adsorption data fitting a pseudo second-order model well. The activation energy, Ea, was found to be 17 kJ/mol, indicating a diffusion-controlled, physical adsorption process. The maximum adsorption was found at initial pH 6. The wet adsorbent showed faster removal with higher uptake than the dry adsorbent, with increased performance as temperature increased (25-45 degrees C). The equilibrium data were found to fit the Langmuir model better than the Freundlich model. The thermodynamic parameters showed that the adsorption process is spontaneous and endothermic. The adsorption mechanism is mainly related to cation exchange and hydrogen bonding.

  7. Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves.

    PubMed

    Bazan, Ovandir; Ortiz, Jayme Pinto; Vieira, Francisco Ubaldo; Vieira, Reinaldo Wilson; Antunes, Nilson; Tabacow, Fabio Bittencourt Dutra; Costa, Eduardo Tavares; Petrucci, Orlando

    2013-01-01

    In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench. To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min.) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves.

  8. Patient information leaflets for antidepressants: are patients getting the information they need?

    PubMed

    Haw, Camilla; Stubbs, Jean

    2011-01-01

    According to European law a comprehensive patient information leaflet (PIL) has to accompany all medicines. In this study we examined the uniformity, adequacy and balance of information contained in UK antidepressant PILs. We studied antidepressant PILs available in the Electronic Medicines Compendium and subjected each to a content analysis. Words were assessed as being positive, negative or neutral. Forty-two PILs concerning 21 different antidepressants and 23 pharmaceutical companies were studied. PILs presented information about side effects in a strikingly heterogeneous way, making it difficult for patients to find the required information. Half the PILs provided no information about how the antidepressant is thought to work. Over 90% stated the antidepressant would take 2-4 weeks to work, although a few PILs indicated earlier onset of improvement. Not all PILs warned about discontinuation syndrome and advice about alcohol was generally that it was prohibited. Almost half of PILs made no mention of St John's wort and its potential for interaction with the antidepressant. Two-thirds of PILs provided no information about the likely duration of treatment. PILs contained far more words judged to be negative rather than positive or neutral. Data were extracted by a single researcher, although inter-rater agreement was high. Further guidance and tightening of the approval process for PILs are needed to ensure they are more standardised in content and contain more information that is wanted by and is useful to patients. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Plasmalogen biosynthesis is spatiotemporally regulated by sensing plasmalogens in the inner leaflet of plasma membranes

    PubMed Central

    Honsho, Masanori; Abe, Yuichi; Fujiki, Yukio

    2017-01-01

    Alkenyl ether phospholipids are a major sub-class of ethanolamine- and choline-phospholipids in which a long chain fatty alcohol is attached at the sn-1 position through a vinyl ether bond. Biosynthesis of ethanolamine-containing alkenyl ether phospholipids, plasmalogens, is regulated by modulating the stability of fatty acyl-CoA reductase 1 (Far1) in a manner dependent on the level of cellular plasmalogens. However, precise molecular mechanisms underlying the regulation of plasmalogen synthesis remain poorly understood. Here we show that degradation of Far1 is accelerated by inhibiting dynamin-, Src kinase-, or flotillin-1-mediated endocytosis without increasing the cellular level of plasmalogens. By contrast, Far1 is stabilized by sequestering cholesterol with nystatin. Moreover, abrogation of the asymmetric distribution of plasmalogens in the plasma membrane by reducing the expression of CDC50A encoding a β-subunit of flippase elevates the expression level of Far1 and plasmalogen synthesis without reducing the total cellular level of plasmalogens. Together, these results support a model that plasmalogens localised in the inner leaflet of the plasma membranes are sensed for plasmalogen homeostasis in cells, thereby suggesting that plasmalogen synthesis is spatiotemporally regulated by monitoring cellular level of plasmalogens. PMID:28272479

  10. Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

    PubMed Central

    Bazan, Ovandir; Ortiz, Jayme Pinto; Vieira Junior, Francisco Ubaldo; Vieira, Reinaldo Wilson; Antunes, Nilson; Tabacow, Fabio Bittencourt Dutra; Costa, Eduardo Tavares; Petrucci Junior, Orlando

    2013-01-01

    Introduction In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench. Objective To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. Methods To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. ) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. Results It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. Conclusions Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves. PMID:24598950

  11. Quasi-Linear Viscoelastic theory applied to internal shearing of porcine aortic valve leaflets.

    PubMed

    Carew, E O; Talman, E A; Boughner, D R; Vesely, I

    1999-08-01

    The elements of Quasi-Linear Viscoelastic (QLV) theory have been applied to model the internal shear mechanics of fresh and glutaraldehyde-fixed porcine aortic valve leaflets. A novel function estimation method was used to extract the material functions from experimental shear data obtained at one strain rate, and the model was used to predict the material response at different strain rates. In general, experiments and predictions were in good agreement, the larger discrepancies being in the prediction of peak stresses and hysteresis in cyclic shear. In shear, fixed tissues are stiffer (mean initial shear modulus, 13 kPa versus 427 Pa), take longer to relax to steady state (mean tau 2 4,736 s versus 1,764 s) with a slower initial relaxation rate (mean magnitude of G(0), 1 s-1 versus 5 s-1), and relax to a lesser extent than fresh tissues (mean percentage stress remaining after relaxation, 60 versus 45 percent). All differences were significant at p = 0.04 or less, except for the initial relaxation slope. We conclude that shear experiments can complement traditional tensile and biaxial experiments toward providing a complete mechanical description of soft biomaterials, particularly when evaluating alternative chemical fixation techniques.

  12. A Tri-Leaflet Nitinol Mesh Scaffold for Engineering Heart Valves.

    PubMed

    Alavi, S Hamed; Soriano Baliarda, Marc; Bonessio, Noemi; Valdevit, Lorenzo; Kheradvar, Arash

    2017-02-01

    The epidemiology of valvular heart disease has significantly changed in the past few decades with aging as one of the main contributing factors. The available options for replacement of diseased valves are currently limited to mechanical and bioprosthetic valves, while the tissue engineered ones that are under study are currently far from clinical approval. The main problem with the tissue engineered heart valves is their progressive deterioration that leads to regurgitation and/or leaflet thickening a few months after implantation. The use of bioresorbable scaffolds is speculated to be one factor affecting these valves' failure. We have previously developed a non-degradable superelastic nitinol mesh scaffold concept that can be used for heart valve tissue engineering applications. It is hypothesized that the use of a non-degradable superelastic nitinol mesh may increase the durability of tissue engineered heart valves, avoid their shrinkage, and accordingly prevent regurgitation. The current work aims to study the effects of the design features on mechanical characteristics of this valve scaffold to attain proper function prior to in vivo implantation.

  13. Report: quantitative estimation of beta-sitosterol, lupeol, quercetin and quercetin glycosides from leaflets of Soymida febrifuga using HPTLC technique.

    PubMed

    Attarde, D L; Aurangabadkar, V M; Belsare, D P; Pal, S C

    2008-07-01

    Soymida febrifuga (Meliaceae) dried leaflets (10 gm) were extracted with petroleum ether. Unsaponifiable matter quantitatively used for sample preparation, labeled as SF-U. Another 10 gm leaflet powder was extracted with methanol and quantitatively used for sample preparation labeled as SF-A. Sample and standard solution were dosage on three different plates and developed in its respective mobile phase plates were scanned using TLC scanner III and estimated using integration software CATs 4.05. Calculations for percentage were done considering standard and sample R(f), AUC and dilution factor. Estimation of beta Sitosterol, Lupeol, Quercetin, Quercetin-3-O-galactoside, Quercetin-3-O-xyloside and Quercetin-3-O-rutinoside were determined as 0.02146% w/w, 0.0377% w/w, 0.4079% w/w, 0.6197% w/w, 2.974% w/w and 3.235% w/w respectively with the help of HPLC techniques.

  14. Key to Syagrus identification using leaflet margin anatomy: Supplement to “A revision of Syagrus (Arecaceae)”

    PubMed Central

    Noblick, Larry R.

    2017-01-01

    Abstract Presented here is an alternative method of identification for species of the Neotropical palm genus Syagrus. It makes use of anatomical characters found in the leaflet margins and can be used for identification when few other vegetative or reproductive morphological characters are available. This anatomical study demonstrates the vast diversity found in a single palm genus and may also help to gain understanding of some possible relationships within the genus. PMID:28785164

  15. Tri-leaflet valve design with a purge flow for heart-assist devices: an in vitro optimization study.

    PubMed

    Timmel, Tobias; Seshadri, Santhosh; Goubergrits, Leonid; Affeld, Klaus; Kertzscher, Ulrich

    2012-01-01

    The objective of this study is to assess the effect of a purge flow on valves of pulsatile heart-assist devices. Clinical applications of these devices are still limited because of frequent thromboembolic complications. These complications often originate at the valves and the unavoidable flow separation regions that are found behind the leaflets. The flow separations cause a long residence time of blood that is considered particularly detrimental. To solve this problem, a valve with a purge flow is proposed. A purge flow is a jet, which is separated from the main blood flow and directed behind the leaflets into the sinus to flush it. Even though the purge flow does not prevent a flow separation, it shortens the residence time of the blood in the sinus. Thus, the purge flow improves the periodic washout of the blood in the region of flow separation. The complex purge flow was investigated in a tri-leaflet valve. The geometrical parameters of the valve were varied systematically. A statistical technique--the Taguchi method--was used to reduce the number of investigated models to 12. The flows through the resulting valve models were numerically simulated and analyzed. The evaluated models with the best results were subsequently investigated experimentally using different methods: hemodynamic tests in a valve tester and flow visualization using the dye washout method. It was shown that the purge flow can effectively wash out the sinus. Therefore, the purge flow valve reduces the potential of a thrombus formation normally associated with the valve.

  16. Lateral suppressor and Goblet act in hierarchical order to regulate ectopic meristem formation at the base of tomato leaflets.

    PubMed

    Rossmann, Susanne; Kohlen, Wouter; Hasson, Alice; Theres, Klaus

    2015-03-01

    In seed plants, new axes of growth are established by the formation of meristems, groups of pluripotent cells that maintain themselves and initiate the formation of lateral organs. After embryonic development, secondary shoot meristems form in the boundary zones between the shoot apical meristem and leaf primordia, the leaf axils. In addition, many plant species develop ectopic meristems at different positions of the plant body. In the compound tomato leaf, ectopic meristems can initiate at the base of leaflets, which are delimited by two distinct boundary zones, referred to as the proximal (PLB) and distal (DLB) leaflet boundaries. We demonstrate that the two leaflet boundaries differ from each other and that ectopic meristem formation is strictly limited to the DLB. Our data suggest that the DLB harbours a group of pluripotent cells that seems to be the launching pad for meristem formation. Initiation of these meristems is dependent on the activities of the transcriptional regulators Goblet (Gob) and Lateral suppressor (Ls), specifically expressed in the DLB. Gob and Ls act in hierarchical order, because Ls transcript accumulation is dependent on Gob activity, but not vice versa. Ectopic meristem formation at the DLB is also observed in other seed plants, like Cardamine pratensis, indicating that it is part of a widespread developmental program. Ectopic meristem formation leads to an increase in the number of buds, enhances the capacity for survival and opens the route to vegetative propagation. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  17. Mapping the literature of perfusion.

    PubMed Central

    Hall, E F

    1999-01-01

    Perfusionists select and operate the equipment necessary for monitoring, supporting, or temporarily replacing the patient's circulatory or respiratory function. There are over 3,000 perfusionists working in U.S. hospitals, medical and perfusionist groups, and as independent contractors. The purpose of this study was to identify the core literature of perfusion and to determine which major databases provide the most thorough access to this literature. This paper is part of the Medical Library Association Nursing and Allied Health Resource Section's project to map the literature of the allied health professions. It uses a bibliometric methodology to identify core journals. A group of forty-three journals was determined to make up the core journal literature of perfusion. MEDLINE provided the best overall indexing coverage for these journals, but librarians and perfusionists will wish to supplement its use with the Cumulative Index to Nursing and Allied Health Literature in order to access the journals written primarily for perfusionists. The study results can guide purchasing and database searching decisions of collection development and reference librarians, encourage the database producer to increase coverage of titles that are unindexed or underindexed, and advise perfusionists of the best access to their core literature. PMID:10427432

  18. Multiphysics simulation of the effect of leaflet thickness inhomogeneity and material anisotropy on the stress-strain distribution on the aortic valve.

    PubMed

    Joda, Akram; Jin, Zhongmin; Haverich, Axel; Summers, Jon; Korossis, Sotirios

    2016-08-16

    This study developed a realistic 3D FSI computational model of the aortic valve using the fixed-grid method, which was eventually employed to investigate the effect of the leaflet thickness inhomogeneity and leaflet mechanical nonlinearity and anisotropy on the simulation results. The leaflet anisotropy and thickness inhomogeneity were found to significantly affect the valve stress-strain distribution. However, their effect on valve dynamics and fluid flow through the valve were minor. Comparison of the simulation results against in-vivo and in-vitro data indicated good agreement between the computational models and experimental data. The study highlighted the importance of simulating multi-physics phenomena (such as fluid flow and structural deformation), regional leaflet thickness inhomogeneity and anisotropic nonlinear mechanical properties, to accurately predict the stress-strain distribution on the natural aortic valve.

  19. Pushing with the pigtail: a novel approach to placing the MitraClip in a patient with a severely restricted posterior mitral leaflet.

    PubMed

    Jones, Brandon M; Tuzcu, E Murat; Kapadia, Samir R

    2015-04-01

    The MitraClip is an US Food and Drug Administration-approved device for inoperable patients with severe degenerative mitral regurgitation (MR) and is under investigation for use in patients with severe functional MR. Simultaneously grasping both leaflets of the mitral valve can be technically challenging, however, in patients with a restricted posterior leaflet. We present one such case in which a pigtail catheter, placed retrograde into the left ventricle, was able to push the ventricular surface of the posterior leaflet into closer approximation with the anterior leaflet, and facilitate successful clip placement. We provide this report in hopes that it will provide a useful strategy for interventionalists faced with this challenging situation. © 2014 Wiley Periodicals, Inc.

  20. Oral alprazolam acutely increases nucleus accumbens perfusion

    PubMed Central

    Wolf, Daniel H.; Pinkham, Amy E.; Satterthwaite, Theodore D.; Ruparel, Kosha; Elliott, Mark A.; Valdez, Jeffrey; Smith, Mark A.; Detre, John A.; Gur, Ruben C.; Gur, Raquel E.

    2014-01-01

    Benzodiazepines treat anxiety, but can also produce euphoric effects, contributing to abuse. Using perfusion magnetic resonance imaging, we provide the first direct evidence in humans that alprazolam (Xanax) acutely increases perfusion in the nucleus accumbens, a key reward-processing region linked to addiction. PMID:23070072

  1. Personality factors correlate with regional cerebral perfusion.

    PubMed

    O'Gorman, R L; Kumari, V; Williams, S C R; Zelaya, F O; Connor, S E J; Alsop, D C; Gray, J A

    2006-06-01

    There is an increasing body of evidence pointing to a neurobiological basis of personality. The purpose of this study was to investigate the biological bases of the major dimensions of Eysenck's and Cloninger's models of personality using a noninvasive magnetic resonance perfusion imaging technique in 30 young, healthy subjects. An unbiased voxel-based analysis was used to identify regions where the regional perfusion demonstrated significant correlation with any of the personality dimensions. Highly significant positive correlations emerged between extraversion and perfusion in the basal ganglia, thalamus, inferior frontal gyrus and cerebellum and between novelty seeking and perfusion in the cerebellum, cuneus and thalamus. Strong negative correlations emerged between psychoticism and perfusion in the basal ganglia and thalamus and between harm avoidance and perfusion in the cerebellar vermis, cuneus and inferior frontal gyrus. These observations suggest that personality traits are strongly associated with resting cerebral perfusion in a variety of cortical and subcortical regions and provide further evidence for the hypothesized neurobiological basis of personality. These results may also have important implications for functional neuroimaging studies, which typically rely on the modulation of cerebral hemodynamics for detection of task-induced activation since personality effects may influence the intersubject variability for both task-related activity and resting cerebral perfusion. This technique also offers a novel approach for the exploration of the neurobiological correlates of human personality.

  2. Technetium myocardial perfusion agents: an introduction

    SciTech Connect

    English, R.J.; Kozlowski, J.; Tumeh, S.S.; Holman, B.L.

    1987-09-01

    This is the third in a series of four Continuing Education articles on developing radiopharmaceuticals. After reading this article, the reader should be able to: 1) understand the basic concepts of myocardial perfusion imaging; and 2) discuss the advantages of the technetium myocardial perfusion complexes over thallium-201.

  3. Luxury perfusion following anterior ischemic optic neuropathy.

    PubMed

    Friedland, S; Winterkorn, J M; Burde, R M

    1996-09-01

    We present five patients who developed luxury perfusion following anterior ischemic optic neuropathy in whom fluorescein angiography was misinterpreted as "capillary hemangioma" or neovascularization of the disc. In each case, the segment of disc hyperemia corresponded to a spared region of visual field. Luxury perfusion represents a reparative autoregulatory reaction to ischemia.

  4. Long term perfusion system supporting adipogenesis

    PubMed Central

    Abbott, Rosalyn D.; Raja, Waseem K.; Wang, Rebecca Y.; Stinson, Jordan A.; Glettig, Dean L.; Burke, Kelly A.; Kaplan, David L.

    2015-01-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogensis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight. PMID:25843606

  5. Myocardial perfusion with rubidium-82. III. Theory relating severity of coronary stenosis to perfusion deficit

    SciTech Connect

    Mullani, N.A.

    1984-11-01

    The relation between the quantitative perfusion deficit, as measured by emission computerized tomography, and the severity of coronary artery stenosis is important for the noninvasive clinical evaluation of coronary artery disease in man. Positron emission tomography allows direct noninvasive measurement of myocardial perfusion and quantification of the size of the perfusion defect. Given this important imformation, a mathematical model has been derived to gauge the severity of a coronary stenosis from quantitative perfusion measurements in the normal and poststenotic regions of the heart. The theoretical basis is presented for relating regional myocardial perfusion and regional perfusion resistance to total, coronary blood flow and resistance at normal resting flow and during maximal coronary vasodilation. The concept of perfusion reserve is presented as a clinical measure of the severity of a stenosis.

  6. [Compromized myocardial perfusion in arrhythmias (author's transl)].

    PubMed

    Simon, H; Neumann, G; Felix, R; Hedde, H; Schaede, A; Thurn, P; Winkler, C

    1977-09-15

    In 7 patients with arrhythmias of various origin the myocardial scintigram displayed either a diffuse or circumscript defect of the perfusion. The coronary arteriogram was normal in all patients. The localized defect of the perfusion in 2 patients was in the region of the upper part of the interventricular septum. Both had a left bundle brunch block. A correlation between the perfusion defect and the electrophysiological abnormality seems probable. The perfusion defect in one of the patients is most probably caused by a previous myocarditis followed by fibrous changes. In the other 6 patients the cause for the perfusion defect is not obvious. A history of myocarditis is missing. The presence of "small vessel disease" in those patients has however to be considered. Our results point to the relation between an abnormality of the microcirculation and arrhythmias in younger patients.

  7. Measuring blood delivery to solitary pulmonary nodules using perfusion magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Wang, Zhifeng; Shen, Li; Gao, Ling; Ford, James C.; Makedon, Fillia S.; Pearlman, Justin D.

    2006-03-01

    With perfusion magnetic resonance imaging (pMRI), perfusion describes the amount of blood passing through a block of tissue in a certain period of time. In pMRI, the tissue having more blood passing through will show higher intensity value as more contrast-labeled blood arrives. Perfusion reflects the delivery of essential nutrients to a block of tissue, and is an important parameter for the tissue status. Considering solitary pulmonary nodules (SPN), perfusion differences between malignant and benign nodules have been studied by different techniques. Much effort has been put into its characterization. In this paper, we proposed and implemented extraction of the SPN time intensity profile to measure blood delivery to solitary pulmonary nodules, describing their perfusion effects. In this method, a SPN time intensity profile is created based on intensity values of the solitary pulmonary nodule in lung pMRI images over time. This method has two steps: nodule tracking and profile clustering. Nodule tracking aligns the solitary pulmonary nodule in pMRI images taken at different time points, dealing with nodule movement resulted from breathing and body movement. Profile clustering implements segmentation of the nodule region and extraction of the time intensity profile of a solitary pulmonary nodule. SPN time intensity profiles reflect patterns of blood delivery to solitary pulmonary nodules, giving us a description of perfusion effect and indirect evidence of tumor angiogenesis. Analysis on SPN time intensity profiles will help the diagnosis of malignant nodules for early lung cancer detection.

  8. Assessment of peripheral tissue perfusion by optical dynamic fluorescence imaging and nonlinear regression modeling

    NASA Astrophysics Data System (ADS)

    Kang, Yujung; Lee, Jungsul; Kwon, Kihwan; Choi, Chulhee

    2010-02-01

    The purpose of this study is to examine the peripheral tissue perfusion rates by time-series analysis of distribution and elimination kinetics of a clinically proven NIR fluorescence probe, indocyanine green (ICG). We developed a new method, dynamic ICG perfusion imaging technique to evaluate peripheral tissue perfusion that employs planar imaging with a CCD digital imaging system and time-series analysis of the spatiotemporal dynamics (150s) of intravenously injected ICG by using nonlinear regression and differential evolution methods. Six parameters (α, β, s, d, m; parameters which depend on an arterial input function (AIF) into a lower extremity and p; perfusion rates in the lower extremity) were estimated by the nonlinear regression modeling method. We have confirmed the validity of our new method by applying the method to a normal control and a patient with peripheral arterial occlusion disease (PAOD). PAOD patient showed a unique AIF curve pattern, which was caused by collateral blood flow bypassing the occluded major artery. The lower extremity tissue perfusion rate of the PAOD patient was estimated as about 35% of those of normal values. These results indicate that ICG perfusion imaging method is sensitive enough to diagnose PAOD and capable of diagnosing functional arterial diseases.

  9. Evaluation of Gastric Conduit Perfusion During Esophagectomy with Indocyanine Green Fluorescence Imaging.

    PubMed

    Schlottmann, Francisco; Patti, Marco G

    2017-08-17

    Anastomotic leakage is a determining factor of morbidity and mortality after an esophagectomy. An adequate blood supply of the gastric conduit is vital to prevent this complication. We aimed to determine the feasibility and usefulness of indocyanine green (ICG) fluorescence imaging to evaluate the gastric conduit perfusion during an esophagectomy. Patients with distal esophageal cancer or esophagogastric junction cancer scheduled for esophagectomy were enrolled in this study. After pulling up the gastric conduit into the chest and before performing the anastomosis, 5 mg of ICG was injected as a bolus. Visual assessment of the blood supply of the gastric conduit was compared with the ICG fluorescence imaging pattern of perfusion. Five patients were included in this study. Hybrid Ivor-Lewis esophagectomy (laparoscopic abdomen and right thoracotomy) was performed in all cases. In all patients, visual assessment of the perfusion of the stomach determined that the conduit was well perfused. In two patients (40%), ICG fluorescence showed an inadequate blood supply of the conduit's tip. Resection of the devitalized portion of the conduit was performed in these two patients. No anastomotic leaks were recorded, and all patients had an uneventful postoperative course. Visual assessment of the gastric conduit may underestimate perfusion and inadequate blood supply. ICG fluorescence imaging is a promising tool to determine the gastric conduit perfusion during an esophagectomy. Prospective studies with larger series are warranted to confirm the usefulness of ICG fluorescence imaging during an esophagectomy.

  10. Evaluation of pulmonary perfusion in lung regions showing isolated xenon-133 ventilation washout defects

    SciTech Connect

    Bushnell, D.L.; Sood, K.B.; Shirazi, P.; Pal, I. )

    1990-08-01

    Xenon-133 washout phase imaging is often used to help determine whether the etiology of a perfusion defect is embolic or due to pulmonary parenchymal pathology, such as chronic obstructive pulmonary disease. This study was designed to evaluate the pulmonary blood flow patterns associated with isolated defects on xenon washout images. Scintigraphic lung studies were reviewed until 100 cases with abnormal ventilation results were obtained. Ventilation abnormalities were compared with the corresponding perfusion scan results at the same anatomic site. Of the 208 individual lung regions with xenon abnormalities, 111 showed isolated washout defects (that is, with normal washin). Ninety-four of these 111 sites showed either normal perfusion or a small, nonsegmental corresponding perfusion defect. Three segmental perfusion defects were noted in association with isolated xenon retention. In each of these cases, however, the patient was felt actually to have pulmonary embolism. Thus, it is recommended that, for interpretation of scintigraphic images in the assessment of pulmonary embolism, lung pathology associated with isolated xenon retention not be considered a potential cause for large or segmental perfusion defects.

  11. Ventilation-perfusion matching in long-term microgravity

    NASA Technical Reports Server (NTRS)

    Verbandt, Y.; Wantier, M.; Prisk, G. K.; Paiva, M.; West, J. B. (Principal Investigator)

    2000-01-01

    We studied the ventilation-perfusion matching pattern in normal gravity (1 G) and short- and long-duration microgravity (microG) using the cardiogenic oscillations in the sulfur hexaflouride (SF(6)) and CO(2) concentration signals during the phase III portion of vital capacity single-breath washout experiments. The signal power of the cardiogenic concentration variations was assessed by spectral analysis, and the phase angle between the oscillations of the two simultaneously expired gases was obtained through cross-correlation. For CO(2), a significant reduction of cardiogenic power was observed in microG, with respect to 1 G, but the reduction was smaller and more variable in the case of SF(6). A shift from an in-phase condition in 1 G to an out-of-phase condition was found for both short- and long-duration microG. We conclude that, although the distribution of ventilation and perfusion becomes more homogeneous in microG, significant inhomogeneities persist and that areas of high perfusion become associated with areas of relatively lower ventilation. In addition, these modifications seem to remain constant during long-term exposure to microG.

  12. Ventilation-perfusion matching in long-term microgravity

    NASA Technical Reports Server (NTRS)

    Verbandt, Y.; Wantier, M.; Prisk, G. K.; Paiva, M.; West, J. B. (Principal Investigator)

    2000-01-01

    We studied the ventilation-perfusion matching pattern in normal gravity (1 G) and short- and long-duration microgravity (microG) using the cardiogenic oscillations in the sulfur hexaflouride (SF(6)) and CO(2) concentration signals during the phase III portion of vital capacity single-breath washout experiments. The signal power of the cardiogenic concentration variations was assessed by spectral analysis, and the phase angle between the oscillations of the two simultaneously expired gases was obtained through cross-correlation. For CO(2), a significant reduction of cardiogenic power was observed in microG, with respect to 1 G, but the reduction was smaller and more variable in the case of SF(6). A shift from an in-phase condition in 1 G to an out-of-phase condition was found for both short- and long-duration microG. We conclude that, although the distribution of ventilation and perfusion becomes more homogeneous in microG, significant inhomogeneities persist and that areas of high perfusion become associated with areas of relatively lower ventilation. In addition, these modifications seem to remain constant during long-term exposure to microG.

  13. Criteria for Viability Assessment of Discarded Human Donor Livers during Ex Vivo Normothermic Machine Perfusion

    PubMed Central

    Karimian, Negin; Weeder, Pepijn D.; de Boer, Marieke T.; Wiersema-Buist, Janneke; Gouw, Annette S. H.; Leuvenink, Henri G. D.; Lisman, Ton; Porte, Robert J.

    2014-01-01

    Although normothermic machine perfusion of donor livers may allow assessment of graft viability prior to transplantation, there are currently no data on what would be a good parameter of graft viability. To determine whether bile production is a suitable biomarker that can be used to discriminate viable from non-viable livers we have studied functional performance as well as biochemical and histological evidence of hepatobiliary injury during ex vivo normothermic machine perfusion of human donor livers. After a median duration of cold storage of 6.5 h, twelve extended criteria human donor livers that were declined for transplantation were ex vivo perfused for 6 h at 37°C with an oxygenated solution based on red blood cells and plasma, using pressure controlled pulsatile perfusion of the hepatic artery and continuous portal perfusion. During perfusion, two patterns of bile flow were identified: (1) steadily increasing bile production, resulting in a cumulative output of ≥30 g after 6 h (high bile output group), and (2) a cumulative bile production <20 g in 6 h (low bile output group). Concentrations of transaminases and potassium in the perfusion fluid were significantly higher in the low bile output group, compared to the high bile output group. Biliary concentrations of bilirubin and bicarbonate were respectively 4 times and 2 times higher in the high bile output group. Livers in the low bile output group displayed more signs of hepatic necrosis and venous congestion, compared to the high bile output group. In conclusion, bile production could be an easily assessable biomarker of hepatic viability during ex vivo machine perfusion of human donor livers. It could potentially be used to identify extended criteria livers that are suitable for transplantation. These ex vivo findings need to be confirmed in a transplant experiment or a clinical trial. PMID:25369327

  14. Criteria for viability assessment of discarded human donor livers during ex vivo normothermic machine perfusion.

    PubMed

    Sutton, Michael E; op den Dries, Sanna; Karimian, Negin; Weeder, Pepijn D; de Boer, Marieke T; Wiersema-Buist, Janneke; Gouw, Annette S H; Leuvenink, Henri G D; Lisman, Ton; Porte, Robert J

    2014-01-01

    Although normothermic machine perfusion of donor livers may allow assessment of graft viability prior to transplantation, there are currently no data on what would be a good parameter of graft viability. To determine whether bile production is a suitable biomarker that can be used to discriminate viable from non-viable livers we have studied functional performance as well as biochemical and histological evidence of hepatobiliary injury during ex vivo normothermic machine perfusion of human donor livers. After a median duration of cold storage of 6.5 h, twelve extended criteria human donor livers that were declined for transplantation were ex vivo perfused for 6 h at 37 °C with an oxygenated solution based on red blood cells and plasma, using pressure controlled pulsatile perfusion of the hepatic artery and continuous portal perfusion. During perfusion, two patterns of bile flow were identified: (1) steadily increasing bile production, resulting in a cumulative output of ≥ 30 g after 6 h (high bile output group), and (2) a cumulative bile production <20 g in 6 h (low bile output group). Concentrations of transaminases and potassium in the perfusion fluid were significantly higher in the low bile output group, compared to the high bile output group. Biliary concentrations of bilirubin and bicarbonate were respectively 4 times and 2 times higher in the high bile output group. Livers in the low bile output group displayed more signs of hepatic necrosis and venous congestion, compared to the high bile output group. In conclusion, bile production could be an easily assessable biomarker of hepatic viability during ex vivo machine perfusion of human donor livers. It could potentially be used to identify extended criteria livers that are suitable for transplantation. These ex vivo findings need to be confirmed in a transplant experiment or a clinical trial.

  15. Descending projections of the hamster intergeniculate leaflet: relationship to the sleep/arousal and visuomotor systems

    NASA Technical Reports Server (NTRS)

    Morin, Lawrence P.; Blanchard, Jane H.

    2005-01-01

    The intergeniculate leaflet (IGL), homolog of the primate pregeniculate nucleus, modulates circadian rhythms. However, its extensive anatomical connections suggest that it may regulate other systems, particularly those for visuomotor function and sleep/arousal. Here, descending IGL-efferent pathways are identified with the anterograde tracer, Phaseolus vulgaris leucoagglutinin, with projections to over 50 brain stem nuclei. Projections of the ventral lateral geniculate are similar, but more limited. Many of the nuclei with IGL afferents contribute to circuitry governing visuomotor function. These include the oculomotor, trochlear, anterior pretectal, Edinger-Westphal, and the terminal nuclei; all layers of the superior colliculus, interstitial nucleus of the medial longitudinal fasciculus, supraoculomotor periaqueductal gray, nucleus of the optic tract, the inferior olive, and raphe interpositus. Other target nuclei are known to be involved in the regulation of sleep, including the lateral dorsal and pedunculopontine tegmentum. The dorsal raphe also receives projections from the IGL and may contribute to both sleep/arousal and visuomotor function. However, the locus coeruleus and medial vestibular nucleus, which contribute to sleep and eye movement regulation and which send projections to the IGL, do not receive reciprocal projections from it. The potential involvement of the IGL with the sleep/arousal system is further buttressed by existing evidence showing IGL-efferent projections to the ventrolateral preoptic area, dorsomedial, and medial tuberal hypothalamus. In addition, the great majority of all regions receiving IGL projections also receive input from the orexin/hypocretin system, suggesting that this system contributes not only to the regulation of sleep, but to eye movement control as well.

  16. Descending projections of the hamster intergeniculate leaflet: relationship to the sleep/arousal and visuomotor systems

    NASA Technical Reports Server (NTRS)

    Morin, Lawrence P.; Blanchard, Jane H.

    2005-01-01

    The intergeniculate leaflet (IGL), homolog of the primate pregeniculate nucleus, modulates circadian rhythms. However, its extensive anatomical connections suggest that it may regulate other systems, particularly those for visuomotor function and sleep/arousal. Here, descending IGL-efferent pathways are identified with the anterograde tracer, Phaseolus vulgaris leucoagglutinin, with projections to over 50 brain stem nuclei. Projections of the ventral lateral geniculate are similar, but more limited. Many of the nuclei with IGL afferents contribute to circuitry governing visuomotor function. These include the oculomotor, trochlear, anterior pretectal, Edinger-Westphal, and the terminal nuclei; all layers of the superior colliculus, interstitial nucleus of the medial longitudinal fasciculus, supraoculomotor periaqueductal gray, nucleus of the optic tract, the inferior olive, and raphe interpositus. Other target nuclei are known to be involved in the regulation of sleep, including the lateral dorsal and pedunculopontine tegmentum. The dorsal raphe also receives projections from the IGL and may contribute to both sleep/arousal and visuomotor function. However, the locus coeruleus and medial vestibular nucleus, which contribute to sleep and eye movement regulation and which send projections to the IGL, do not receive reciprocal projections from it. The potential involvement of the IGL with the sleep/arousal system is further buttressed by existing evidence showing IGL-efferent projections to the ventrolateral preoptic area, dorsomedial, and medial tuberal hypothalamus. In addition, the great majority of all regions receiving IGL projections also receive input from the orexin/hypocretin system, suggesting that this system contributes not only to the regulation of sleep, but to eye movement control as well.

  17. Sexual health-related information delivery - are patient information leaflets still relevant?

    PubMed

    Varma, Rick; Chung, Charles; Townsend, Amanda; Power, Melissa

    2016-06-01

    Background Patient information leaflets (PILs) are widely utilised within publically funded sexual health clinics to deliver sexual health-related information (SHRI); however, their continued value to clients in the era of social media is unclear. This study aimed to evaluate clients' opinions on three newly developed PILs and examine client views on other forms of SHRI delivery. An anonymous self-administered questionnaire was completed by clients attending the Western Sydney Sexual Health Centre (WSSHC) in 2012. High-risk population (HRP) vs non-high-risk population (non-HRP) views on PILs vs alternative methods of SHRI delivery were analysed by using Mann-Whitney U, Wilcoxon, McNemar and χ(2) tests. Over half (210/315; (67%)) of the consecutive clients from a culturally diverse population completed the survey. Sex workers (SW) and young people (YP) were significantly likely to have a high school education than non-HRP (P<0.039 and P<0.032). Overall, PILs, a clinic website and the Sexual Health Information Link (SHIL), a state-wide website and telephone line, were ranked significantly higher as a means of SHRI delivery on a Likert scale than newer technologies including Facebook (P<0.001), email (P<0.001), mobile phone applications (P<0.001), TVs in waiting rooms (P<0.001) and business cards (P<0.001). There was no significant difference in opinion between HRP and non-HRP. This study provides evidence for the ongoing use of PILs to deliver SHRI to clinic attendees, in conjunction with other forms of SHRI delivery such as websites and SHIL. Novel methods may require additional consumer engagement and a greater understanding of specific population's needs.

  18. Mitral leaflet modeling: Importance of in vivo shape and material properties.

    PubMed

    Stevanella, Marco; Krishnamurthy, Gaurav; Votta, Emiliano; Swanson, Julia C; Redaelli, Alberto; Ingels, Neil B

    2011-08-11

    The anterior mitral leaflet (AML) is a thin membrane that withstands high left ventricular (LV) pressure pulses 100,000 times per day. The presence of contractile cells determines AML in vivo stiffness and complex geometry. Until recently, mitral valve finite element (FE) models have neglected both of these aspects. In this study we assess their effect on AML strains and stresses, hypothesizing that these will differ significantly from those reported in literature. Radiopaque markers were sewn on the LV, the mitral annulus, and AML in sheep hearts, and their four-dimensional coordinates obtained with biplane video fluoroscopy. Employing in vivo data from three representative hearts, AML FE models were created from the marker coordinates at the end of isovolumic relaxation assumed as the unloaded reference state. AML function was simulated backward through systole, applying the measured trans-mitral pressure on AML LV surface and marker displacements on AML boundaries. Simulated AML displacements and curvatures were consistent with in vivo measurements, confirming model accuracy. AML circumferential strains were mostly tensile (1-3%), despite being compressive (-1%) near the commissures. Radial strains were compressive in the belly (-1 to -0.2%), and tensile (2-8%) near the free edge. These results differ significantly from those of previous FE models. They reflect the synergy of high tissue stiffness, which limits tensile circumferential strains, and initial compound curvature, which forces LV pressure to compress AML radially. The obtained AML shape may play a role not only in preventing mitral regurgitation, but also in optimizing LV outflow fluid dynamics.

  19. On the Presence of Affine Fibril and Fiber Kinematics in the Mitral Valve Anterior Leaflet

    PubMed Central

    Lee, Chung-Hao; Zhang, Will; Liao, Jun; Carruthers, Christopher A.; Sacks, Jacob I.; Sacks, Michael S.

    2015-01-01

    In this study, we evaluated the hypothesis that the constituent fibers follow an affine deformation kinematic model for planar collagenous tissues. Results from two experimental datasets were utilized, taken at two scales (nanometer and micrometer), using mitral valve anterior leaflet (MVAL) tissues as the representative tissue. We simulated MVAL collagen fiber network as an ensemble of undulated fibers under a generalized two-dimensional deformation state, by representing the collagen fibrils based on a planar sinusoidally shaped geometric model. The proposed approach accounted for collagen fibril amplitude, crimp period, and rotation with applied macroscopic tissue-level deformation. When compared to the small angle x-ray scattering measurements, the model fit the data well, with an r2 = 0.976. This important finding suggests that, at the homogenized tissue-level scale of ∼1 mm, the collagen fiber network in the MVAL deforms according to an affine kinematics model. Moreover, with respect to understanding its function, affine kinematics suggests that the constituent fibers are largely noninteracting and deform in accordance with the bulk tissue. It also suggests that the collagen fibrils are tightly bounded and deform as a single fiber-level unit. This greatly simplifies the modeling efforts at the tissue and organ levels, because affine kinematics allows a straightforward connection between the macroscopic and local fiber strains. It also suggests that the collagen and elastin fiber networks act independently of each other, with the collagen and elastin forming long fiber networks that allow for free rotations. Such freedom of rotation can greatly facilitate the observed high degree of mechanical anisotropy in the MVAL and other heart valves, which is essential to heart valve function. These apparently novel findings support modeling efforts directed toward improving our fundamental understanding of tissue biomechanics in healthy and diseased conditions

  20. Myocardial perfusion assessment with contrast echocardiography

    NASA Astrophysics Data System (ADS)

    Desco, Manuel; Ledesma-Carbayo, Maria J.; Santos, Andres; Garcia-Fernandez, Miguel A.; Marcos-Alberca, Pedro; Malpica, Norberto; Antoranz, Jose C.; Garcia-Barreno, Pedro

    2001-05-01

    Assessment of intramyocardial perfusion by contrast echocardiography is a promising new technique that allows to obtain quantitative parameters for the assessment of ischemic disease. In this work, a new methodology and a software prototype developed for this task are presented. It has been validated with Coherent Contrast Imaging (CCI) images acquired with an Acuson Sequoia scanner. Contrast (Optison microbubbles) is injected continuously during the scan. 150 images are acquired using low mechanical index U/S pulses. A burst of high mechanical index pulses is used to destroy bubbles, thus allowing to detect the contrast wash-in. The stud is performed in two conditions: rest and pharmacologically induced stress. The software developed allows to visualized the study (cine) and to select several ROIs within the heart wall. The position of these ROIs along the cardiac cycle is automatically corrected on the basis of the gradient field, and they can also be manually corrected in case the automatic procedure fails. Time curves are analyzed according to a parametric model that incorporates both contrast inflow rate and cyclic variations. Preliminary clinical results on 80 patients have allowed us to identify normal and pathological patterns and to establish the correlation of quantitative parameters with the real diagnosis.

  1. Dopaminergic Therapy Modulates Cortical Perfusion in Parkinson Disease With and Without Dementia According to Arterial Spin Labeled Perfusion Magnetic Resonance Imaging.

    PubMed

    Lin, Wei-Che; Chen, Pei-Chin; Huang, Yung-Cheng; Tsai, Nai-Wen; Chen, Hsiu-Ling; Wang, Hung-Chen; Lin, Tsu-Kung; Chou, Kun-Hsien; Chen, Meng-Hsiang; Chen, Yi-Wen; Lu, Cheng-Hsien

    2016-02-01

    Arterial spin labeling (ASL) magnetic resonance imaging analyses allow for the quantification of altered cerebral blood flow, and provide a novel means of examining the impact of dopaminergic treatments. The authors examined the cerebral perfusion differences among 17 Parkinson disease (PD) patients, 17 PD with dementia (PDD) patients, and 17 healthy controls and used ASL-MRI to assess the effects of dopaminergic therapies on perfusion in the patients. The authors demonstrated progressive widespread cortical hypoperfusion in PD and PDD and robust effects for the dopaminergic therapies. Specifically, dopaminergic medications further decreased frontal lobe and cerebellum perfusion in the PD and PDD groups, respectively. These patterns of hypoperfusion could be related to cognitive dysfunctions and disease severity. Furthermore, desensitization to dopaminergic therapies in terms of cortical perfusion was found as the disease progressed, supporting the concept that long-term therapies are associated with the therapeutic window narrowing. The highly sensitive pharmaceutical response of ASL allows clinicians and researchers to easily and effectively quantify the absolute perfusion status, which might prove helpful for therapeutic planning.

  2. Dopaminergic Therapy Modulates Cortical Perfusion in Parkinson Disease With and Without Dementia According to Arterial Spin Labeled Perfusion Magnetic Resonance Imaging

    PubMed Central

    Lin, Wei-Che; Chen, Pei-Chin; Huang, Yung-Cheng; Tsai, Nai-Wen; Chen, Hsiu-Ling; Wang, Hung-Chen; Lin, Tsu-Kung; Chou, Kun-Hsien; Chen, Meng-Hsiang; Chen, Yi-Wen; Lu, Cheng-Hsien

    2016-01-01

    Abstract Arterial spin labeling (ASL) magnetic resonance imaging analyses allow for the quantification of altered cerebral blood flow, and provide a novel means of examining the impact of dopaminergic treatments. The authors examined the cerebral perfusion differences among 17 Parkinson disease (PD) patients, 17 PD with dementia (PDD) patients, and 17 healthy controls and used ASL-MRI to assess the effects of dopaminergic therapies on perfusion in the patients. The authors demonstrated progressive widespread cortical hypoperfusion in PD and PDD and robust effects for the dopaminergic therapies. Specifically, dopaminergic medications further decreased frontal lobe and cerebellum perfusion in the PD and PDD groups, respectively. These patterns of hypoperfusion could be related to cognitive dysfunctions and disease severity. Furthermore, desensitization to dopaminergic therapies in terms of cortical perfusion was found as the disease progressed, supporting the concept that long-term therapies are associated with the therapeutic window narrowing. The highly sensitive pharmaceutical response of ASL allows clinicians and researchers to easily and effectively quantify the absolute perfusion status, which might prove helpful for therapeutic planning. PMID:26844450

  3. The Mouse Isolated Perfused Kidney Technique.

    PubMed

    Czogalla, Jan; Schweda, Frank; Loffing, Johannes

    2016-11-17

    The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a prerequisite for studying the physiology of the isolated organ and for many innovative applications that may be possible in the future, including perfusion decellularization for kidney bioengineering or the administration of anti-rejection or genome-editing drugs in high doses to prime the kidney for transplantation. During the time of the perfusion, the kidney can be manipulated, renal function can be assessed, and various pharmaceuticals administered. After the procedure, the kidney can be transplanted or processed for molecular biology, biochemical analysis, or microscopy. This paper describes the perfusate and the surgical technique needed for the ex vivo perfusion of mouse kidneys. Details of the perfusion apparatus are given and data are presented showing the viability of the kidney's preparation: renal blood flow, vascular resistance, and urine data as functional, transmission electron micrographs of different nephron segments as morphological readouts, and western blots of transport proteins of different nephron segments as molecular readout.

  4. Diurnal Curve of the Ocular Perfusion Pressure

    PubMed Central

    Moreira, TCA; Bezerra, BSP; Vianello, MP; Corradi, J; Dorairaj, SK; Prata, TS

    2016-01-01

    ABSTRACT Purpose: To describe the diurnal variation of the ocular perfusion pressure (OPP) in normal, suspects and glaucoma patients. Materials and methods: Seventy-nine subjects were enrolled in a prospective study. The diurnal curve of intraocular pressure (IOP) was performed and blood pressure measurements were obtained. Each participant was grouped into one of the following based upon the clinical evaluation of the optic disk, IOP and standard achromatic perimetry (SAP): 18 eyes were classified as normal (normal SAP, normal optic disk evaluation and IOP < 21 mm Hg in two different measurements), 30 eyes as glaucoma suspect (GS) (normal SAP and mean deviation (MD), C/D ration > 0.5 or asymmetry > 0.2 and/or ocular hypertension), 31 eyes as early glaucoma (MD < -6 dB, glaucomatous optic neuropathy and SAP and MDs on SAP. Standard achromatic perimetry was performed with the Octopus 3.1.1 Dynamic 24-2 program. Intraocular pressure and blood pressure measurements were taken at 6 am, 9 am, 12, 3 and 6 pm. The patients stayed in the seated position for 5 minutes prior to blood pressure measurements. Results: The mean IOP values in all groups did not follow any regular pattern. The peak IOP was found to be greater in suspect [18.70 ± 3.31 (mm Hg ± SD)] and glaucoma (18.77 ± 4.30 mm Hg) patients as compared to normal subjects (16.11 ± 2.27 mm Hg). In studying the diurnal variation of the OPP, we found lower values at 3 pm in normals (34.21 ± 2.07 mm Hg), at 9 am in suspects (54.35 ± 3.32 mm Hg) and at 12 pm in glaucoma patients (34.84 ± 1.44 mm Hg). Conclusion: Each group has a specific OPP variation during the day with the most homogeneous group being the suspect one. It is important to keep studying the IOP and OPP variation for increased comprehension of the pathophysiology of glaucomatous optic neuropathy. How to cite this article: Kanadani FN, Moreira TCA, Bezerra BSP, Vianello MP, Corradi J, Dorairaj SK, Prata TS. Diurnal Curve of the Ocular Perfusion

  5. Cracking the perfusion code?: Laser-assisted Indocyanine Green angiography and combined laser Doppler spectrophotometry for intraoperative evaluation of tissue perfusion in autologous breast reconstruction with DIEP or ms-TRAM flaps.

    PubMed

    Ludolph, Ingo; Arkudas, Andreas; Schmitz, Marweh; Boos, Anja M; Taeger, Christian D; Rother, Ulrich; Horch, Raymund E; Beier, Justus P

    2016-10-01

    The aim of this prospective study was to assess the correlation of flap perfusion analysis based on laser-assisted Indocyanine Green (ICG) angiography with combined laser Doppler spectrophotometry in autologous breast reconstruction using free DIEP/ms-TRAM flaps. Between February 2014 and July 2015, 35 free DIEP/ms-TRAM flaps were included in this study. Besides the clinical evaluation of flaps, intraoperative perfusion dynamics were assessed by means of laser-assisted ICG angiography and post-capillary oxygen saturation and relative haemoglobin content (rHb) using combined laser Doppler spectrophotometry. Correlation of the aforementioned parameters was analysed, as well as the impact on flap design and postoperative complications. Flap survival rate was 100%. There were no partial flap losses. In three cases, flap design was based on the angiography, contrary to clinical evaluation and spectrophotometry. The final decision on the inclusion of flap areas was based on the angiographic perfusion pattern. Angiography and spectrophotometry showed a correlation in most of the cases regarding tissue perfusion, post-capillary oxygen saturation and relative haemoglobin content. Laser-assisted ICG angiography is a useful tool for intraoperative evaluation of flap perfusion in autologous breast reconstruction with DIEP/ms-TRAM flaps, especially in decision making in cases where flap perfusion is not clearly assessable by clinical signs and exact determination of well-perfused flap margins is difficult to obtain. It provides an objective real-time analysis of flap perfusion, with high sensitivity for the detection of poorly perfused flap areas. Concerning the topographical mapping of well-perfused flap areas, laser-assisted angiography is superior to combined laser Doppler spectrophotometry.

  6. Human cortical perfusion and the arterial pulse: a near-infrared spectroscopy study

    PubMed Central

    Kwan, Hon C; Cheng, Anita; Liu, Ruth; Borrett, Donald S

    2004-01-01

    Background The pulsatile nature of the arterial pulse induces a pulsatile perfusion pattern which can be observed in human cerebral cortex with non-invasive near-infrared spectroscopy. The present study attempts to establish a quantitative relation between these two events, even in situations of very weak signal-to-noise ratio in the cortical perfusion signal. The arterial pulse pattern was extracted from the left middle finger by means of plethesmographic techniques. Changes in cortical perfusion were detected with a continuous-wave reflectance spectrophotometer on the scalp overlying the left prefrontal cortex. Cross-correlation analysis was performed to provide evidence for a causal relation between the arterial pulse and relative changes in cortical total hemoglobin. In addition, the determination of the statistical significance of this relation was established by the use of phase-randomized surrogates. Results The results showed statistically significant cross correlation between the arterial and perfusion signals. Conclusions The approach designed in the present study can be utilized for a quantitative and continuous assessment of the perfusion states of the cerebral cortex in experimental and clinical settings even in situations of extremely low signal-to-noise ratio. PMID:15113424

  7. Calf muscle perfusion as measured with magnetic resonance imaging to assess peripheral arterial disease.

    PubMed

    Brunner, Gerd; Bismuth, Jean; Nambi, Vijay; Ballantyne, Christie M; Taylor, Addison A; Lumsden, Alan B; Morrisett, Joel D; Shah, Dipan J

    2016-11-01

    We hypothesized that skeletal muscle perfusion is impaired in peripheral arterial disease (PAD) patients compared to healthy controls and that perfusion patterns exhibit marked differences across five leg muscle compartments including the anterior muscle group (AM), lateral muscle group (LM), deep posterior muscle group (DM), soleus (SM), and the gastrocnemius muscle (GM). A total of 40 individuals (26 PAD patients and 14 healthy controls) underwent contrast-enhanced magnetic resonance imaging (CE-MRI) utilizing a reactive hyperemia protocol. Muscle perfusion maps were developed for AM, LM, DM, SM, and GM. Perfusion maps were analyzed over the course of 2 min, starting at local pre-contrast arrival, to study early-to-intermediate gadolinium enhancement. PAD patients had a higher fraction of hypointense voxels at pre-contrast arrival for all five muscle compartments compared with healthy controls (p < 0.0005). Among PAD patients, the fraction of hypointense voxels of the AM, LM, and GM were inversely correlated with the estimated glomerular filtration rate (eGFR; r = -0.509, p = 0.008; r = -0.441, p = 0.024; and r = -0.431, p = 0.028, respectively). CE-MRI-based skeletal leg muscle perfusion is markedly reduced in PAD patients compared with healthy controls and shows heterogeneous patterns across calf muscle compartments.

  8. Dissociative Part-Dependent Resting-State Activity in Dissociative Identity Disorder: A Controlled fMRI Perfusion Study

    PubMed Central

    Schlumpf, Yolanda R.; Reinders, Antje A. T. S.; Nijenhuis, Ellert R. S.; Luechinger, Roger; van Osch, Matthias J. P.; Jäncke, Lutz

    2014-01-01

    Background In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the “Emotional Part” (EP) and the “Apparently Normal Part” (ANP), have different biopsychosocial reactions to supraliminal and subliminal trauma-related cues and that these reactions cannot be mimicked by fantasy prone healthy controls nor by actors. Methods Arterial spin labeling perfusion MRI was used to test the hypotheses that ANP and EP in DID have different perfusion patterns in response to rest instructions, and that perfusion is different in actors who were instructed to simulate ANP and EP. In a follow-up study, regional cerebral blood flow of DID patients was compared with the activation pattern of healthy non-simulating controls. Results Compared to EP, ANP showed elevated perfusion in bilateral thalamus. Compared to ANP, EP had increased perfusion in the dorsomedial prefrontal cortex, primary somatosensory cortex, and motor-related areas. Perfusion patterns for simulated ANP and EP were different. Fitting their reported role-play strategies, the actors activated brain structures involved in visual mental imagery and empathizing feelings. The follow-up study demonstrated elevated perfusion in the left temporal lobe in DID patients, whereas non-simulating healthy controls had increased activity in areas which mediate the mental construction of past and future episodic events. Conclusion DID involves dissociative part-dependent resting-state differences. Compared to ANP, EP activated brain structures involved in self-referencing and sensorimotor actions more. Actors had different perfusion patterns compared to genuine ANP and EP. Comparisons of neural activity for individuals with DID and non-DID simulating controls suggest that the resting-state features of ANP and EP in DID are not due to imagination. The findings are

  9. Dissociative part-dependent resting-state activity in dissociative identity disorder: a controlled FMRI perfusion study.

    PubMed

    Schlumpf, Yolanda R; Reinders, Antje A T S; Nijenhuis, Ellert R S; Luechinger, Roger; van Osch, Matthias J P; Jäncke, Lutz

    2014-01-01

    In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the "Emotional Part" (EP) and the "Apparently Normal Part" (ANP), have different biopsychosocial reactions to supraliminal and subliminal trauma-related cues and that these reactions cannot be mimicked by fantasy prone healthy controls nor by actors. Arterial spin labeling perfusion MRI was used to test the hypotheses that ANP and EP in DID have different perfusion patterns in response to rest instructions, and that perfusion is different in actors who were instructed to simulate ANP and EP. In a follow-up study, regional cerebral blood flow of DID patients was compared with the activation pattern of healthy non-simulating controls. Compared to EP, ANP showed elevated perfusion in bilateral thalamus. Compared to ANP, EP had increased perfusion in the dorsomedial prefrontal cortex, primary somatosensory cortex, and motor-related areas. Perfusion patterns for simulated ANP and EP were different. Fitting their reported role-play strategies, the actors activated brain structures involved in visual mental imagery and empathizing feelings. The follow-up study demonstrated elevated perfusion in the left temporal lobe in DID patients, whereas non-simulating healthy controls had increased activity in areas which mediate the mental construction of past and future episodic events. DID involves dissociative part-dependent resting-state differences. Compared to ANP, EP activated brain structures involved in self-referencing and sensorimotor actions more. Actors had different perfusion patterns compared to genuine ANP and EP. Comparisons of neural activity for individuals with DID and non-DID simulating controls suggest that the resting-state features of ANP and EP in DID are not due to imagination. The findings are consistent with TSDP and inconsistent with the idea

  10. [Perfusion computed tomography for diffuse liver diseases].

    PubMed

    Schmidt, S A; Juchems, M S

    2012-08-01

    Perfusion computed tomography (CT) has its main application in the clinical routine diagnosis of neuroradiological problems. Polyphase multi-detector spiral computed tomography is primarily used in liver diagnostics. The use of perfusion CT is also possible for the diagnostics and differentiation of diffuse hepatic diseases. The differentiation between cirrhosis and cirrhosis-like parenchymal changes is possible. It also helps to detect early stages of malignant tumors. However, there are some negative aspects, particularly that of radiation exposure. This paper summarizes the technical basics and possible applications of perfusion CT in cases of diffuse liver disease and weighs up the advantages and disadvantages of the examinations.

  11. Variation in Perfusion Strategies for Neonatal and Infant Aortic Arch Repair: Contemporary Practice in the STS Congenital Heart Surgery Database.

    PubMed

    Meyer, David B; Jacobs, Jeffrey P; Hill, Kevin; Wallace, Amelia S; Bateson, Brian; Jacobs, Marshall L

    2016-09-01

    Regional cerebral perfusion (RCP) is used as an adjunct or alternative to deep hypothermic circulatory arrest (DHCA) for neonates and infants undergoing aortic arch repair. Clinical studies have not demonstrated clear superiority of either strategy, and multicenter data regarding current use of these strategies are lacking. We sought to describe the variability in contemporary practice patterns for use of these techniques. The Society of Thoracic Surgeons Congenital Heart Surgery Database (2010-2013) was queried to identify neonates and infants whose index operation involved aortic arch repair with cardiopulmonary bypass. Perfusion strategy was classified as isolated DHCA, RCP (with less than or equal to ten minutes of DHCA), or mixed (RCP with more than ten minutes of DHCA). Data were analyzed for the entire cohort and stratified by operation subgroups. Overall, 4,523 patients (105 centers) were identified; median age seven days (interquartile range: 5.0-13.0). The most prevalent perfusion strategy was RCP (43%). Deep hypothermic circulatory arrest and mixed perfusion accounted for 32% and 16% of cases, respectively. In all, 59% of operations involved some period of RCP. Regional cerebral perfusion was the most prevalent perfusion strategy for each operation subgroup. Neither age nor weight was associated with perfusion strategy, but reoperations were less likely to use RCP (31% vs 45%, P < .001). The combined duration of RCP and DHCA in the RCP group was longer than the DHCA time in the DHCA group (45 vs 36 minutes, P < .001). There is considerable variability in practice regarding perfusion strategies for arch repair in neonates and infants. In contemporary practice, RCP is the most prevalent perfusion strategy for these procedures. Use of DHCA is also common. Further investigation is warranted to ascertain possible relative merits of the various perfusion techniques. © The Author(s) 2016.

  12. Basic T1 Perfusion magnetic resonance imaging evaluation of the therapeutic effect of neoadjuvant chemotherapy in locally advanced cervical cancer.

    PubMed

    Fu, Chun; Feng, Xiaoyan; Bian, Dujun; Du, Wanping; Wang, Xiangquan; Zhao, Yan

    2013-09-01

    The objective of this study was to evaluate the dynamic changes of blood perfusion coinciding with tumor regression after neoadjuvant chemotherapy (NACT) in locally advanced cervical cancer (LACC). Thirty patients with LACC received conventional 3.0-T magnetic resonance imaging and perfusion-weighted imaging scans at 3 different times (before NACT, 2 weeks after the first NACT, and 2 weeks after the second NACT). Characteristics of time-intensity diagrams and patterns of blood perfusion maps according to the parameter of area under the curve (AUC) were observed. Eight perfusion parameters were compared among 3 time points at 2 different chemotherapy-sensitive groups by the software of Basic T1 Perfusion. The effective chemotherapy rate was 73.3% (22/30). The characteristic of time-intensity diagrams in cervical cancer was a rapid onset with plateau. There were 3 patterns of AUC perfusion maps. The common perfusion map was rich blood supply type in the effective chemotherapy group and peripheral blood supply type in the ineffective chemotherapy group. Four parameter values (relative enhancement, maximum enhancement, wash-in rate, and AUC) were significantly reduced 2 weeks after the second NACT than those before the therapy (P = 0.000; P = 0.009; P = 0.011; and P = 0.000) in the effective chemotherapy group, especially the value of relative enhancement 2 weeks after the first NACT, was obviously decreased compared to that before the therapy (P = 0.042). The value of time to peak 2 weeks after the second NACT was significantly longer than that before the therapy in the effective chemotherapy group (P = 0.001). There were no obvious changes of blood perfusion parameters among the 3 different times in the ineffective chemotherapy group. Tumor blood perfusion has obviously decreased after effective NACT in the treatment of LACC.

  13. Evolution of pulmonary perfusion defects demonstrated with contrast-enhanced dynamic MR perfusion imaging.

    PubMed

    Howarth, N R; Beziat, C; Berthezène, Y

    1999-01-01

    Pulmonary perfusion defects can be demonstrated with contrast-enhanced dynamic MR perfusion imaging. We present the case of a patient with a pulmonary artery sarcoma who presented with a post-operative pulmonary embolus and was followed in the post-operative period with dynamic contrast-enhanced MR perfusion imaging. This technique allows rapid imaging of the first passage of contrast material through the lung after bolus injection in a peripheral vein. To our knowledge, this case report is the first to describe the use of this MR technique in showing the evolution of peripheral pulmonary perfusion defects associated with pulmonary emboli.

  14. Constitutive modeling of jugular vein-derived venous valve leaflet tissues.

    PubMed

    Kaul, Nayyan; Huang, Hsiao-Ying Shadow

    2017-11-01

    Venous valve tissues, though used in vein reconstruction surgeries and bioprosthetic valves with moderate success, have not been extensively studied with respect to their structure. Their inherent anisotropic, non-linear behavior combined with severe diseases which affect veins, such as chronic venous insufficiency, warrant understanding the structure and material behavior of these tissues. Hence, before any bioprosthetic grafts may be used in place of tissues, it is of the utmost importance to understand the mechanical and structural properties of these tissues as this may lead to higher success rates for valve replacement surgeries. The longevity of the bioprosthetics may also increase if the manufactured grafts behave the same as native valves. Building on the scant information about the uniaxial and biaxial mechanical properties of jugular venous valves and wall tissues from previous studies, the current focus of our investigation lies in understanding the material behavior by establishing a phenomenological strain energy-based constitutive relation for the tissues. We used bovine veins to study the behavior of valve leaflet tissue and adjoining wall tissue (from the proximal and distal ends of the veins) under different biaxial testing protocols. We looked at the behavior of numerical partial derivatives of the strain energy to select a suitable functional form for the strain energy for wall and valve tissues. Using this strain energy descriptor, we determined the Cauchy stress and compared it with experimental results under additional sets of displacement-controlled biaxial testing protocols to find material specific model parameters by the Powell's method algorithm. Results show that whereas wall tissue strain energy can be explained using a polynomial non-linear function, the valve tissue, due to higher non-linearities, requires an exponential function. This study may provide useful information for the primary stages of bioprosthetic designs and replacement

  15. Characters of aerated compost tea from immature compost that limit colonization of bean leaflets by Botrytis cinerea.

    PubMed

    Palmer, A K; Evans, K J; Metcalf, D A

    2010-11-01

    The aim was to produce and characterize an aerated compost tea (ACT) that suppressed growth of the plant pathogen Botrytis cinerea. Three different open-windrow composts were sampled weekly from the early secondary mesophilic stage until maturity. Each 10kg of compost sample was extracted in 30 l of aerated water for 24, 48 or 72h. Relative to water, all batches of ACT applied to detached bean leaflets reduced lesion development following single-point inoculations of B. cinerea. There was a significant linear, inverse relationship between the internal windrow temperature of compost (≤51°C) used to prepare ACT and the extent of lesion development. Bacterial diversity in ACTs from one windrow was highest using compost sampled at 48°C. The compost weight-to-water volume ratios of 1:3, 1:10 or 1:30, using compost sampled from a fourth windrow at 50°C, also produced ACTs that reduced the growth of B. cinerea on bean leaflets. The '1 : 3' ACT, and to a lesser degree the same ACT filtered to remove micro-organisms, inhibited the germination of B. cinerea conidia. ACT produced using the methods reported here suppressed the growth of B. cinerea on bean leaflets, with an abundant and diverse microbial community likely to contribute to pathogen suppression. This is the first report of the use of immature compost to produce a pathogen-suppressive ACT, suggesting that compost stage is an important production variable. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  16. Luminal distension as a possible consequence of experimental intestinal perfusion

    PubMed Central

    Wingate, David; Hyams, Ashley; Phillips, Sidney

    1974-01-01

    In an experimental jejunal perfusion study, distress in healthy subjects occurred during eight out of 16 perfusions in which intestinal secretion was provoked. Calculation demonstrates the volumetric consequences of inadequate recovery of secretory perfusates, and analysis of the perfusion studies shows that distress was significantly associated with poor recovery of the perfusate. These observations are pertinent to increasing interest in the phenomenon of intestinal fluid secretion. PMID:4435588

  17. Improved exercise myocardial perfusion during lidoflazine therapy

    SciTech Connect

    Shapiro, W.; Narahara, K.A.; Park, J.

    1983-11-01

    Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise.

  18. Pancreas transplants: Evaluation using perfusion scintigraphy

    SciTech Connect

    Kuni, C.C.; du Cret, R.P.; Boudreau, R.J.

    1989-07-01

    To determine the value of scintigraphic perfusion studies in evaluating pancreas transplant patients, we reviewed 56 of these studies in 22 patients who had 27 transplants. Seventeen patients underwent two or more studies. The perfusion studies were performed with 20 mCi (740 MBq) of 99mTc-DTPA injected as a bolus followed by eight to 16 serial 2-sec images and a 500,000-count immediate static image. Images were evaluated for (1) the time and intensity of pancreatic peak radioactivity relative to the time and intensity of the iliac arterial peak; (2) relative pancreatic to iliac arterial intensity on the static image; and (3) size, homogeneity, and definition of the pancreas. Clinical diagnoses at the time of scintigraphy of normal function (n = 36), rejection (n = 13), pancreatitis (n = 6), or arterial thrombosis (n = 1) were based on insulin requirement, urine amylase, serum glucose, serum amylase, response to therapy, cultures, CT, MR, sonography, scintigraphy with 67Ga or 111In-WBCs, percutaneous drainage results, angiography, surgery, and pathologic examination of resected transplants. Three 99mTc-DTPA perfusion studies showed no pancreatic perfusion, four showed decreasing perfusion on serial studies, and five showed progressive loss of definition of the pancreas on serial studies. Of the three patients with no detectable perfusion, one had a normally functioning transplant, one had arterial thrombosis with transplant infarction, and one had severe rejection with minimal function. Decreasing perfusion was associated with rejection in three patients and pancreatitis in one. Decreasing definition was seen in four patients with rejection and one with pancreatitis. We conclude that perfusion scintigraphy is useful, primarily when performed serially, although nonspecific for evaluating pancreas transplants.

  19. Vicarious Audiovisual Learning in Perfusion Education

    PubMed Central

    Rath, Thomas E.; Holt, David W.

    2010-01-01

    Abstract: Perfusion technology is a mechanical and visual science traditionally taught with didactic instruction combined with clinical experience. It is difficult to provide perfusion students the opportunity to experience difficult clinical situations, set up complex perfusion equipment, or observe corrective measures taken during catastrophic events because of patient safety concerns. Although high fidelity simulators offer exciting opportunities for future perfusion training, we explore the use of a less costly low fidelity form of simulation instruction, vicarious audiovisual learning. Two low fidelity modes of instruction; description with text and a vicarious, first person audiovisual production depicting the same content were compared. Students (n = 37) sampled from five North American perfusion schools were prospectively randomized to one of two online learning modules, text or video. These modules described the setup and operation of the MAQUET ROTAFLOW standalone centrifugal console and pump. Using a 10 question multiple-choice test, students were assessed immediately after viewing the module (test #1) and then again 2 weeks later (test #2) to determine cognition and recall of the module content. In addition, students completed a questionnaire assessing the learning preferences of today’s perfusion student. Mean test scores from test #1 for video learners (n = 18) were significantly higher (88.89%) than for text learners (n = 19) (74.74%), (p < .05). The same was true for test #2 where video learners (n = 10) had an average score of 77% while text learners (n = 9) scored 60% (p < .05). Survey results indicated video learners were more satisfied with their learning module than text learners. Vicarious audiovisual learning modules may be an efficacious, low cost means of delivering perfusion training on subjects such as equipment setup and operation. Video learning appears to improve cognition and retention of learned content and may play an important

  20. Reducing antibiotic use for acute bronchitis in primary care: blinded, randomised controlled trial of patient information leaflet

    PubMed Central

    Macfarlane, John; Holmes, William; Gard, Philip; Thornhill, David; Macfarlane, Rosamund; Hubbard, Richard

    2002-01-01

    Objective To assess whether sharing the uncertainty of the value of antibiotics for acute bronchitis in the form of written and verbal advice affects the likelihood of patients taking antibiotics. Design Nested, single blind, randomised controlled trial. Setting Three suburban general practices in Nottingham Participants 259 previously well adults presenting with acute bronchitis. Intervention In group A, 212 patients were judged by their general practitioner not to need antibiotics that day but were given a prescription to use if they got worse and standard verbal reassurance. Half of them (106) were also given an information leaflet. All patients in group B (47) were judged to need antibiotics and were given a prescription and encouraged to use it. Main outcome measures Antibiotic use in the next two weeks. Reconsultation for the same symptoms in the next month. Results In group A fewer patients who received the information leaflet took antibiotics compared with those who did not receive the leaflet (49 v 63, risk ratio 0.76, 95% confidence interval 0.59 to 0.97, P=0.04). Numbers reconsulting were similar (11 v 14). In group B, 44 patients took the antibiotics. Conclusion Most previously well adults with acute bronchitis were judged not to need antibiotics. Reassuring these patients and sharing the uncertainty about prescribing in a information leaflet supported by verbal advice is a safe strategy and reduces antibiotic use. What is already known on this topicMost adults with acute bronchitis who consult their general practitioner will receive antibioticsFor most patients antibiotics do not modify the natural course of the symptomsThe widespread belief among patients that infection is the problem and antibiotics the solution has considerable influence on prescribing by general practitioners, even when they judge that antibiotics are not definitely indicatedWhat this study addsGeneral practitioners judged that about four in five adults with acute bronchitis did

  1. Role of perfusion imaging in acute stroke.

    PubMed

    Sillanpää, N

    2013-03-01

    Imaging has a central role in the diagnosis and classification of acute stroke, the triage of patients to different treatment approaches and the prediction of the clinical outcome and the risk of hemorrhagic complications. A multimodal imaging protocol that includes a perfusion study allows diagnostics beyond anatomical findings by enabling the characterization of the ischemic brain tissue and the cerebral hemodynamic state. This information potentially leads to more accurate clinical decision making with the intention to select the right patients for different revascularization therapies regardless of fixed time windows. Perfusion imaging enables the detection and quantification of the irreversibly damaged infarct core and the at-risk penumbra. Parameters derived from perfusion studies can serve as surrogate markers for stroke severity and are independent predictors of the clinical outcome and the occurrence of hemorrhagic complications. The validation and standardization of the perfusion methodology is still ongoing. Currently there is emerging but no high level evidence that perfusion imaging improves the clinical outcome or has a direct impact on the decision to treat the patient with intravenous thrombolytic therapy or intra-arterial interventions. Thus, definite guidelines on the role of the perfusion imaging in the context of acute stroke cannot yet be given.

  2. Hydroxyethyl starch solution for extracorporeal tissue perfusion.

    PubMed

    Taeger, Christian D; Friedrich, Oliver; Drechsler, Caroline; Weigand, Annika; Hobe, Frieder; Geppert, Carol I; Münch, Frank; Birkholz, Torsten; Buchholz, Rainer; Horch, Raymund E; Präbst, Konstantin

    2016-11-04

    In the field of free flap transfer in reconstructive surgery, the trans- or replanted tissue always undergoes cell damage during ischemia to a more or less strong extent. In previous studies we already showed that conserving muscle transplants by means of extracorporeal perfusion over a period of 6 hours by using a crystalloid solution for perfusion. However, we observed significant edema formation. In this study we aimed at reducing the edema formation by using an iso-oncotic colloid as perfusion solution. This way we wanted to evaluate a possible new application of hydroxyl-ethyl starch in an extracorporeal setup to exploit potential benefits of the colloid.Examined parameters include the muscles' functionality with external field stimulation, histological examination and edema formation. Perfused muscles showed a statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, as perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. Substituting the electrolyte perfusion solution with a colloidal one shows the tendency to reduce the edema formation however without statistical significance.

  3. Readability Analysis of the Package Leaflets for Biological Medicines Available on the Internet Between 2007 and 2013: An Analytical Longitudinal Study.

    PubMed

    Piñero-López, María Ángeles; Modamio, Pilar; Lastra, Cecilia F; Mariño, Eduardo L

    2016-05-25

    The package leaflet included in the packaging of all medicinal products plays an important role in the transmission of medicine-related information to patients. Therefore, in 2009, the European Commission published readability guidelines to try to ensure that the information contained in the package leaflet is understood by patients. The main objective of this study was to calculate and compare the readability levels and length (number of words) of the package leaflets for biological medicines in 2007, 2010, and 2013. The sample of this study included 36 biological medicine package leaflets that were downloaded from the European Medicines Agency website in three different years: 2007, 2010, and 2013. The readability of the selected package leaflets was obtained using the following readability formulas: SMOG grade, Flesch-Kincaid grade level, and Szigriszt's perspicuity index. The length (number of words) of the package leaflets was also measured. Afterwards, the relationship between these quantitative variables (three readability indexes and length) and categorical (or qualitative) variables were analyzed. The categorical variables were the year when the package leaflet was downloaded, the package leaflet section, type of medicine, year of authorization of biological medicine, and marketing authorization holder. The readability values of all the package leaflets exceeded the sixth-grade reading level, which is the recommended value for health-related written materials. No statistically significant differences were found between the three years of study in the readability indexes, although differences were observed in the case of the length (P=.002), which increased over the study period. When the relationship between readability indexes and length and the other variables was analyzed, statistically significant differences were found between package leaflet sections (P<.001) and between the groups of medicine only with regard to the length over the three studied

  4. Readability Analysis of the Package Leaflets for Biological Medicines Available on the Internet Between 2007 and 2013: An Analytical Longitudinal Study

    PubMed Central

    2016-01-01

    Background The package leaflet included in the packaging of all medicinal products plays an important role in the transmission of medicine-related information to patients. Therefore, in 2009, the European Commission published readability guidelines to try to ensure that the information contained in the package leaflet is understood by patients. Objective The main objective of this study was to calculate and compare the readability levels and length (number of words) of the package leaflets for biological medicines in 2007, 2010, and 2013. Methods The sample of this study included 36 biological medicine package leaflets that were downloaded from the European Medicines Agency website in three different years: 2007, 2010, and 2013. The readability of the selected package leaflets was obtained using the following readability formulas: SMOG grade, Flesch-Kincaid grade level, and Szigriszt’s perspicuity index. The length (number of words) of the package leaflets was also measured. Afterwards, the relationship between these quantitative variables (three readability indexes and length) and categorical (or qualitative) variables were analyzed. The categorical variables were the year when the package leaflet was downloaded, the package leaflet section, type of medicine, year of authorization of biological medicine, and marketing authorization holder. Results The readability values of all the package leaflets exceeded the sixth-grade reading level, which is the recommended value for health-related written materials. No statistically significant differences were found between the three years of study in the readability indexes, although differences were observed in the case of the length (P=.002), which increased over the study period. When the relationship between readability indexes and length and the other variables was analyzed, statistically significant differences were found between package leaflet sections (P<.001) and between the groups of medicine only with regard

  5. Perfusion of surgical cavity wall enhancement in early post-treatment MR imaging may stratify the time-to-progression in glioblastoma.

    PubMed

    Park, Ji Eun; Ryu, Kyoung Hwa; Kim, Ho Sung; Kim, Hyo Won; Shim, Woo Hyun; Jung, Seung Chai; Choi, Choong Gon; Kim, Sang Joon; Kim, Jeong Hoon

    2017-01-01

    To determine if perfusion in surgical cavity wall enhancement (SCWE) obtained in early post-treatment MR imaging can stratify time-to-progression (TTP) in glioblastoma. This study enrolled 60 glioblastoma patients with more than 5-mm-thick SCWEs as detected on contrast-enhanced MR imaging after concurrent chemoradiation therapy. Two independent readers categorized the shape and perfusion state of SCWEs as nodular or non-nodular and as having positive or negative perfusion compared with the contralateral grey matter on arterial spin labeling (ASL). The perfusion fraction on ASL within the contrast-enhancing lesion was calculated. The independent predictability of TTP was analyzed using the Kaplan-Meier method and Cox proportional hazards modelling. The perfusion fraction was higher in the non-progression group, significantly for reader 2 (P = 0.03) and borderline significantly for reader 1 (P = 0.08). A positive perfusion state and (P = 0.02) a higher perfusion fraction of the SCWE were found to become an independent predictor of longer TTP (P = 0.001 for reader 1 and P < 0.001 for reader 2). The contrast enhancement pattern did not become a TTP predictor. Assessment of perfusion in early post-treatment MR imaging can stratify TTP in patients with glioblastoma for adjuvant temozolomide therapy. Positive perfusion in SCWEs can become a predictor of a longer TTP.

  6. Perfusion of surgical cavity wall enhancement in early post-treatment MR imaging may stratify the time-to-progression in glioblastoma

    PubMed Central

    Kim, Hyo Won; Shim, Woo Hyun; Jung, Seung Chai; Choi, Choong Gon; Kim, Sang Joon; Kim, Jeong Hoon

    2017-01-01

    Objective To determine if perfusion in surgical cavity wall enhancement (SCWE) obtained in early post-treatment MR imaging can stratify time-to-progression (TTP) in glioblastoma. Materials and methods This study enrolled 60 glioblastoma patients with more than 5-mm-thick SCWEs as detected on contrast-enhanced MR imaging after concurrent chemoradiation therapy. Two independent readers categorized the shape and perfusion state of SCWEs as nodular or non-nodular and as having positive or negative perfusion compared with the contralateral grey matter on arterial spin labeling (ASL). The perfusion fraction on ASL within the contrast-enhancing lesion was calculated. The independent predictability of TTP was analyzed using the Kaplan-Meier method and Cox proportional hazards modelling. Results The perfusion fraction was higher in the non-progression group, significantly for reader 2 (P = 0.03) and borderline significantly for reader 1 (P = 0.08). A positive perfusion state and (P = 0.02) a higher perfusion fraction of the SCWE were found to become an independent predictor of longer TTP (P = 0.001 for reader 1 and P < 0.001 for reader 2). The contrast enhancement pattern did not become a TTP predictor. Conclusion Assessment of perfusion in early post-treatment MR imaging can stratify TTP in patients with glioblastoma for adjuvant temozolomide therapy. Positive perfusion in SCWEs can become a predictor of a longer TTP. PMID:28732091

  7. An educational leaflet improves response to invitation for screening for arthritis in patients with psoriasis in primary care, but only in practices in the most deprived areas.

    PubMed

    Coates, Laura C; Savage, Laura; Waxman, Robin; McGonagle, Dennis G; Moverley, Anna R; Helliwell, Philip S

    2017-03-01

    This study hypothesises that an educational leaflet about psoriatic arthritis (PsA) will improve psoriasis patients' attendance for screening for PsA. A random sample of patients ≥18 years old with a coded diagnosis of psoriasis and no diagnosis of PsA, rheumatoid arthritis or ankylosing spondylitis were identified from five GP surgeries in Yorkshire, UK. Patients were randomised 1:1 to receive study information alone or with the educational leaflet, with an invitation to attend for a screening examination by a dermatologist and rheumatologist. Nine hundred thirty-two invitation packs were sent to recruit 191 (20.5%) participants. One hundred sixty-nine (88.5%) had current or previous psoriasis and 17 (10.1%) had previously undiagnosed PsA. The estimated prevalence of PsA was 18.1% (95% CI: 16.2, 20.1%).The response rate was lower than expected and was not significantly higher when patients received the educational leaflet (22.8 vs 18.3%, p = 0.08). Response rates varied by practice (14.7 to 30.6%). However, deprivation scores for each practice revealed a significant increase in response with the leaflet for deprivation decile of 3 (p < 0.001) but no significant differences in the other practices. An educational leaflet about PsA improves attendance for screening in primary care, but only in those practices with higher levels of socioeconomic deprivation.

  8. Knowledge level of primary school teachers regarding traumatic dental injuries and their emergency management before and after receiving an informative leaflet.

    PubMed

    Arikan, Volkan; Sönmez, Hayriye

    2012-04-01

    The aim of this study was to evaluate via a questionnaire the knowledge level of primary school teachers in Ankara, Turkey, regarding dental trauma; to inform them on the subject through a leaflet; and to evaluate the effectiveness of the leaflet by reapplying the questionnaire. A questionnaire was distributed to 500 teachers in seven randomly selected primary schools. The questionnaire consisted of four different scenarios presented with photographs and a total of eight questions on crown fracture, lateral luxation, root fracture, and avulsion. After responding to the questionnaire, teachers were given a leaflet containing information about traumatic dental injuries and their emergency management. After 1 month, the same questionnaire was distributed, and the responses collected. A total of 450 of 500 teachers responded to the questionnaire. Initial responses indicated the knowledge level of teachers to be quite low. Following the distribution of the information leaflet, the rate of correct answers increased for each of the individual questions, and the total scores for the questionnaire increased significantly (P = 0.0001). There is a clear need to inform teachers about traumatic dental injuries. The use of educational leaflets can be a successful and appropriate means of providing teachers with information. © 2011 John Wiley & Sons A/S.

  9. Epidermal growth factor receptors are localized to lipid rafts that contain a balance of inner and outer leaflet lipids: a shotgun lipidomics study.

    PubMed

    Pike, Linda J; Han, Xianlin; Gross, Richard W

    2005-07-22

    The epidermal growth factor (EGF) receptor partitions into lipid rafts made using a detergent-free method, but is extracted from low density fractions by Triton X-100. By screening several detergents, we identified Brij 98 as a detergent in which the EGF receptor is retained in detergent-resistant membrane fractions. To identify the difference in lipid composition between those rafts that harbored the EGF receptor (detergent-free and Brij 98-resistant) and those that did not (Triton X-100-resistant), we used multidimensional electrospray ionization mass spectrometry to perform a lipidomics study on these three raft preparations. Although all three raft preparations were similarly enriched in cholesterol, the EGF receptor-containing rafts contained more ethanolamine glycerophospholipids and less sphingomyelin than did the non-EGF receptor-containing Triton X-100 rafts. As a result, the detergent-free and Brij 98-resistant rafts exhibited a balance of inner and outer leaflet lipids, whereas the Triton X-100 rafts contained a preponderance of outer leaflet lipids. Furthermore, in all raft preparations, the outer leaflet phospholipid species were significantly different from those in the bulk membrane, whereas the inner leaflet lipids were quite similar to those found in the bulk membrane. These findings indicate that the EGF receptor is retained only in rafts that exhibit a lipid distribution compatible with a bilayer structure and that the selection of phospholipids for inclusion into rafts occurs mainly on the outer leaflet lipids.

  10. Dielectrophoresis-based cellular microarray chip for anticancer drug screening in perfusion microenvironments.

    PubMed

    Hsiung, Lo-Chang; Chiang, Chi-Ling; Wang, Chen-Ho; Huang, Yu-Hsu; Kuo, Ching-Te; Cheng, Ji-Yen; Lin, Ching-Hung; Wu, Victoria; Chou, Hsien-Yeh; Jong, De-Shien; Lee, Hsinyu; Wo, Andrew M

    2011-07-21

    We present a dielectrophoresis (DEP)-based cellular microarray chip for cell-based anticancer drug screening in perfusion microenvironments. Human breast cancer cells, MCF7, were seeded into the chip and patterned via DEP forces onto the planar interdigitated ring electrode (PIRE) arrays. Roughly, only one third of the cell amount was required for the chip compared to that for a 96-well plate control. Drug concentrations (cisplatin or docetaxel) were stably generated by functional integration of a concentration gradient generator (CGG) and an anti-crosstalk valve (ACV) to treat cells for 24 hours. Cell viability was quantified using a dual staining method. Results of cell patterning show substantial uniformity of patterned cells (92 ± 5 cells per PIRE). Furthermore, after 24 hour drug perfusion, no statistical significance in dose-responses between the chip and the 96-well plate controls was found. The IC(50) value from the chip also concurred with the values from the literature. Moreover, the perfusion culture exhibited reproducibility of drug responses of cells on different PIREs in the same chamber. The chip would enable applications where cells are of limited supply, and supplement microfluidic perfusion cultures for clinical practices.

  11. Myocardial perfusion abnormalities in chemical warfare patients intoxicated with mustard gas.

    PubMed

    Gholamrezanezhad, Ali; Saghari, Mohsen; Vakili, Arsalan; Mirpour, Sahar; Farahani, Mohammad Hossein

    2007-04-01

    Mustard agents are of the major chemical agents used during Iran-Iraq war. There are no reports concerning long-term cardiac effects. The aim was to assess the scintigraphic pattern of myocardial perfusion in patients intoxicated with blistering gases. We analyzed myocardial perfusion scans of 22 consecutive intoxicated patients (21 male and 1 female, all < 44 years) and compared results with 14 controls. Only those patients and controls were entered whose 10-year risk of coronary artery disease (Framingham criteria) was <5%. Also only those patients were experimented upon that had currently other confirmed complications of intoxication (respiratory, cutaneous and ocular complications). All patients underwent a 1-day stress and rest protocol using (99m)Tc-MIBI. Images were assessed visually and quantitatively using Cedars Sinai program. The prevalence of nonhomogeneity of uptake and left and right ventricular enlargement in both visual and quantitative analyses were higher in the mustard exposed patients than unexposed controls. The prevalence of ischemia was higher in the exposed patients (P < 0.05). Cavity to myocardium ratio, as an established and validated measure of ejection fraction, was also significantly lower in the warfare patients than the controls. In so far it lies in our knowledge, this is the first report concerning the scintigraphic pattern of myocardial perfusion in mustard intoxicated patients. Based on the results, the pattern of myocardial perfusion in these patients is significantly different from normal controls, which could resemble either coronary artery disease or mild cardiomyopathic changes.

  12. Malaria parasite CelTOS targets the inner leaflet of cell membranes for pore-dependent disruption

    PubMed Central

    Jimah, John R; Salinas, Nichole D; Sala-Rabanal, Monica; Jones, Nathaniel G; Sibley, L David; Nichols, Colin G; Schlesinger, Paul H; Tolia, Niraj H

    2016-01-01

    Apicomplexan parasites contain a conserved protein CelTOS that, in malaria parasites, is essential for traversal of cells within the mammalian host and arthropod vector. However, the molecular role of CelTOS is unknown because it lacks sequence similarity to proteins of known function. Here, we determined the crystal structure of CelTOS and discovered CelTOS resembles proteins that bind to and disrupt membranes. In contrast to known membrane disruptors, CelTOS has a distinct architecture, specifically binds phosphatidic acid commonly present within the inner leaflet of plasma membranes, and potently disrupts liposomes composed of phosphatidic acid by forming pores. Microinjection of CelTOS into cells resulted in observable membrane damage. Therefore, CelTOS is unique as it achieves nearly universal inner leaflet cellular activity to enable the exit of parasites from cells during traversal. By providing novel molecular insight into cell traversal by apicomplexan parasites, our work facilitates the design of therapeutics against global pathogens. DOI: http://dx.doi.org/10.7554/eLife.20621.001 PMID:27906127

  13. The Impact of Fluid Inertia on In Vivo Estimation of Mitral Valve Leaflet Constitutive Properties and Mechanics.

    PubMed

    Bark, David L; Dasi, Lakshmi P

    2016-05-01

    We examine the influence of the added mass effect (fluid inertia) on mitral valve leaflet stress during isovolumetric phases. To study this effect, oscillating flow is applied to a flexible membrane at various frequencies to control inertia. Resulting membrane strain is calculated through a three-dimensional reconstruction of markers from stereo images. To investigate the effect in vivo, the analysis is repeated on a published dataset for an ovine mitral valve (Journal of Biomechanics 42(16): 2697-2701). The membrane experiment demonstrates that the relationship between pressure and strain must be corrected with a fluid inertia term if the ratio of inertia to pressure differential approaches 1. In the mitral valve, this ratio reaches 0.7 during isovolumetric contraction for an acceleration of 6 m/s(2). Acceleration is reduced by 72% during isovolumetric relaxation. Fluid acceleration also varies along the leaflet during isovolumetric phases, resulting in spatial variations in stress. These results demonstrate that fluid inertia may be the source of the temporally and spatially varying stiffness measurements previously seen through inverse finite element analysis of in vivo data during isovolumetric phases. This study demonstrates that there is a need to account for added mass effects when analyzing in vivo constitutive relationships of heart valves.

  14. [Effects of using an information leaflet in reducing perioperative anxiety and pain in patients undergoing urological surgery].

    PubMed

    Miguel Romeo, M Carmen; Sagardoy Muniesa, Lorena

    2014-01-01

    The preoperative anxiety state is mainly caused by the fear of the circumstances surrounding the intervention. Anxiety causes increased postoperative pain, and a prolonged length of stay in hospital, which directly affect the cost of care. To evaluate the effects of providing an anaesthesia information leaflet on postoperative anxiety and pain in patients undergoing urological surgery in the Miguel Servet Hospital. A prospective quasi-experimental study of 100 cases, 51 of whom made up the intervention group who received the information leaflet, with the remaining 49 cases being in the control group. The Hospital Anxiety and Depression Scale and the visual analogue scale for pain were assessed in both groups, before and after surgery. Of the 100 patients, 72% were male and 28% female, with an average age of 67.3 years (standard deviation, 9.7). In the intervention group, 21.6% showed anxiety before surgery and 0% in the postoperative period. In the control group 30.6% presented anxiety during the preoperative period and 4% in the postoperative period (χ(2) Pearson 5.20, P=.023). The study showed a direct relationship between preoperative anxiety and postoperative pain (χ(2) Pearson 10.519, P=.001). Good information about the surgical process reduces anxiety levels in the postoperative period. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  15. Is a cleft in the anterior leaflet of an otherwise normal mitral valve an atrioventricular canal malformation?

    PubMed

    Sigfússon, G; Ettedgui, J A; Silverman, N H; Anderson, R H

    1995-08-01

    This study sought to ascertain the surgical anatomy of a cleft in the left atrioventricular (AV) valve. Important morphologic differences exist between hearts with a cleft in the anterior leaflet of an otherwise normal mitral valve and those with a so-called cleft in the left AV valve when there is an AV septal defect, but it has been customary to link the lesions together on developmental grounds. Eight autopsied specimens with a cleft in the aortic (or anterior) leaflet of the mitral valve were studied in detail, and echocardiograms from 21 patients with such a cleft were compared with the specimens and with findings typical of the so-called partial AV canal and other forms of AV septal defect. The structure and direction of the cleft, location of the papillary muscles within the left ventricle and AV junctional morphology of hearts with an otherwise normally structured mitral valve were significantly different from typical findings in hearts with AV septal defects. It is necessary to distinguish morphologically a cleft in an otherwise normally structured mitral valve in hearts with separate right and left AV junctions from the trifoliate left component of a common AV valve in hearts with an AV septal defect and a common AV junction because the disposition of the AV conduction tissues varies markedly between the lesions.

  16. Design and Validation of a Novel Bioreactor to Subject Aortic Valve Leaflets to Side-Specific Shear Stress

    PubMed Central

    Sun, Ling; Rajamannan, Nalini M.; Sucosky, Philippe

    2014-01-01

    Hemodynamic stresses are presumed to play an important role in the development of calcific aortic valve disease (CAVD). The elucidation of the shear stress mechanisms involved in the pathogenesis of CAVD has been hampered by the complexity of the native unsteady and side-specific valvular flow environment. To address this gap, this article describes the design and validation of a novel device to expose leaflet samples to time-dependent side-specific shear stress. The device built on a double cone-and-plate geometry was dimensioned based on our previous single-sided shear stress device that minimizes secondary flow effects inherent to this geometry. A fluid–structure interaction (FSI) model was designed to predict the actual shear stress produced on a tissue sample mounted in the new device. Staining was performed on porcine leaflets conditioned in the new bioreactor to assess endothelial integrity and cellular apoptosis. The FSI results demonstrated good agreement between the target (native) and the actual side-specific shear stress produced on a tissue sample. No significant difference in endothelial integrity and cellular apoptosis was detected between samples conditioned for 96 h and fresh controls. This new device will enable the investigation of valvular response to normal and pathologic hemodynamics and the potential mechano-etiology of CAVD. PMID:21455792

  17. Non-negative constraint for image-based breathing gating in ultrasound hepatic perfusion data

    NASA Astrophysics Data System (ADS)

    Wu, Kaizhi; Ding, Mingyue; Chen, Xi; Deng, Wenjie; Zhang, Zhijun

    2015-12-01

    Images acquired during free breathing using contrast enhanced ultrasound hepatic perfusion imaging exhibits a periodic motion pattern. It needs to be compensated for if a further accurate quantification of the hepatic perfusion analysis is to be executed. To reduce the impact of respiratory motion, image-based breathing gating algorithm was used to compensate the respiratory motion in contrast enhanced ultrasound. The algorithm contains three steps of which respiratory kinetics extracted, image subsequences determined and image subsequences registered. The basic performance of the algorithm was to extract the respiratory kinetics of the ultrasound hepatic perfusion image sequences accurately. In this paper, we treated the kinetics extracted model as a non-negative matrix factorization (NMF) problem. We extracted the respiratory kinetics of the ultrasound hepatic perfusion image sequences by non-negative matrix factorization (NMF). The technique involves using the NMF objective function to accurately extract respiratory kinetics. It was tested on simulative phantom and used to analyze 6 liver CEUS hepatic perfusion image sequences. The experimental results show the effectiveness of our proposed method in quantitative and qualitative.

  18. Spatial optimization in perfusion bioreactors improves bone tissue-engineered construct quality attributes.

    PubMed

    Papantoniou, Ioannis; Guyot, Yann; Sonnaert, Maarten; Kerckhofs, Greet; Luyten, Frank P; Geris, Liesbet; Schrooten, Jan

    2014-12-01

    Perfusion bioreactors have shown great promise for tissue engineering applications providing a homogeneous and consistent distribution of nutrients and flow-induced shear stresses throughout tissue-engineered constructs. However, non-uniform fluid-flow profiles found in the perfusion chamber entrance region have been shown to affect tissue-engineered construct quality characteristics during culture. In this study a whole perfusion and construct, three dimensional (3D) computational fluid dynamics approach was used in order to optimize a critical design parameter such as the location of the regular pore scaffolds within the perfusion bioreactor chamber. Computational studies were coupled to bioreactor experiments for a case-study flow rate. Two cases were compared in the first instance seeded scaffolds were positioned immediately after the perfusion chamber inlet while a second group was positioned at the computationally determined optimum distance were a steady state flow profile had been reached. Experimental data showed that scaffold location affected significantly cell content and neo-tissue distribution, as determined and quantified by contrast enhanced nanoCT, within the constructs both at 14 and 21 days of culture. However, gene expression level of osteopontin and osteocalcin was not affected by the scaffold location. This study demonstrates that the bioreactor chamber environment, incorporating a scaffold and its location within it, affects the flow patterns within the pores throughout the scaffold requiring therefore dedicated optimization that can lead to bone tissue engineered constructs with improved quality attributes. © 2014 Wiley Periodicals, Inc.

  19. Metabolic profiling during ex vivo machine perfusion of the human liver.

    PubMed

    Bruinsma, Bote G; Sridharan, Gautham V; Weeder, Pepijn D; Avruch, James H; Saeidi, Nima; Özer, Sinan; Geerts, Sharon; Porte, Robert J; Heger, Michal; van Gulik, Thomas M; Martins, Paulo N; Markmann, James F; Yeh, Heidi; Uygun, Korkut

    2016-03-03

    As donor organ shortages persist, functional machine perfusion is under investigation to improve preservation of the donor liver. The transplantation of donation after circulatory death (DCD) livers is limited by poor outcomes, but its application may be expanded by ex vivo repair and assessment of the organ before transplantation. Here we employed subnormothermic (21 °C) machine perfusion of discarded human livers combined with metabolomics to gain insight into metabolic recovery during machine perfusion. Improvements in energetic cofactors and redox shifts were observed, as well as reversal of ischemia-induced alterations in selected pathways, including lactate metabolism and increased TCA cycle intermediates. We next evaluated whether DCD livers with steatotic and severe ischemic injury could be discriminated from 'transplantable' DCD livers. Metabolomic profiling was able to cluster livers with similar metabolic patterns based on the degree of injury. Moreover, perfusion parameters combined with differences in metabolic factors suggest variable mechanisms that result in poor energy recovery in injured livers. We conclude that machine perfusion combined with metabolomics has significant potential as a clinical instrument for the assessment of preserved livers.

  20. Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion

    PubMed Central

    Ghisleni, Carmen; Bollmann, Steffen; Biason-Lauber, Anna; Poil, Simon-Shlomo; Brandeis, Daniel; Martin, Ernst; Michels, Lars; Hersberger, Martin; Suckling, John

    2015-01-01

    Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS) as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women). Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women. PMID:26356576

  1. Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion.

    PubMed

    Ghisleni, Carmen; Bollmann, Steffen; Biason-Lauber, Anna; Poil, Simon-Shlomo; Brandeis, Daniel; Martin, Ernst; Michels, Lars; Hersberger, Martin; Suckling, John; Klaver, Peter; O'Gorman, Ruth L

    2015-01-01

    Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS) as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women). Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women.

  2. GPU-accelerated voxelwise hepatic perfusion quantification

    NASA Astrophysics Data System (ADS)

    Wang, H.; Cao, Y.

    2012-09-01

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using compute unified device architecture-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, nonlinear least-squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626 400 voxels in a patient's liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10-6. The method will be useful for generating liver perfusion images in clinical settings.

  3. GPU-accelerated voxelwise hepatic perfusion quantification.

    PubMed

    Wang, H; Cao, Y

    2012-09-07

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using compute unified device architecture-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, nonlinear least-squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626 400 voxels in a patient's liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10(-6). The method will be useful for generating liver perfusion images in clinical settings.

  4. GPU-Accelerated Voxelwise Hepatic Perfusion Quantification

    PubMed Central

    Wang, H; Cao, Y

    2012-01-01

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using CUDA-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, non-linear least squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626400 voxels in a patient’s liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10−6. The method will be useful for generating liver perfusion images in clinical settings. PMID:22892645

  5. The Relation Between Collagen Fibril Kinematics and Mechanical Properties in the Mitral Valve Anterior Leaflet

    SciTech Connect

    Liao,J.; Yang, L.; Grashow, J.; Sacks, M.

    2007-01-01

    We have recently demonstrated that the mitral valve anterior leaflet (MVAL) exhibited minimal hysteresis, no strain rate sensitivity, stress relaxation but not creep (Grashow et al., 2006, Ann Biomed Eng., 34(2), pp. 315-325; Grashow et al., 2006, Ann Biomed. Eng., 34(10), pp. 1509-1518). However, the underlying structural basis for this unique quasi-elastic mechanical behavior is presently unknown. As collagen is the major structural component of the MVAL, we investigated the relation between collagen fibril kinematics (rotation and stretch) and tissue-level mechanical properties in the MVAL under biaxial loading using small angle X-ray scattering. A novel device was developed and utilized to perform simultaneous measurements of tissue level forces and strain under a planar biaxial loading state. Collagen fibril D-period strain ({epsilon}{sub D}) and the fibrillar angular distribution were measured under equibiaxial tension, creep, and stress relaxation to a peak tension of 90 N/m. Results indicated that, under equibiaxial tension, collagen fibril straining did not initiate until the end of the nonlinear region of the tissue-level stress-strain curve. At higher tissue tension levels, {epsilon}{sub D} increased linearly with increasing tension. Changes in the angular distribution of the collagen fibrils mainly occurred in the tissue toe region. Using {epsilon}{sub D}, the tangent modulus of collagen fibrils was estimated to be 95.5{+-}25.5 MPa, which was {approx}27 times higher than the tissue tensile tangent modulus of 3.58{+-}1.83 MPa. In creep tests performed at 90 N/m equibiaxial tension for 60 min, both tissue strain and D remained constant with no observable changes over the test length. In contrast, in stress relaxation tests performed for 90 min {epsilon}{sub D} was found to rapidly decrease in the first 10 min followed by a slower decay rate for the remainder of the test. Using a single exponential model, the time constant for the reduction in collagen

  6. The mesenterially perfused rat small intestine: A versatile approach for pharmacological testings.

    PubMed

    Schreiber, Dominik; Klotz, Markus; Laures, Kerstin; Clasohm, Jasmin; Bischof, Michael; Schäfer, Karl-Herbert

    2014-05-01

    Pharmaceutical compounds enter the body via several major natural gateways; i.e. the lung, the skin and the gastrointestinal tract. Drug application during surgical operations can lead to severe impairment of gastrointestinal motility, which can contribute to a paralytic ileus. Here we investigated an ex vivo perfused small intestine model that allows us to ascertain the influence of pharmaceuticals upon the gut. Corresponding segments from the proximal jejunum of adult rats were used. Their mesenteric arteries and veins were cannulated and the jejunal segment excised. The individual segments were placed in a custom designed perfusion chamber and perfusion performed through the intestinal lumen as well as the mesenteric superior artery. Three test drugs, which are commonly used in anesthesiology; i.e. pentobarbital, propofol and ketamine were administered via the blood vessels. Their effects upon gastrointestinal motility patterns were evaluated by optical measurements. Longitudinal and pendular movements were distinguishable and separately analyzed. Pharmacological effects of the individual substances could be investigated. Propofol (50-200 μg/ml) was found to decrease intestinal motility, especially longitudinal movements in a dose dependent manner. Pentobarbital decreased intestinal motility only at high concentrations, above 2.5 mg/ml. A dose of 2.5 mg/ml lead to an increase in longitudinal- and pendular movements in comparison to control, while ketamine (2.5-10 mg/ml) did not alter intestinal motility at all. Histological examination of the perfused segments revealed only minor changes in tissue morphology after perfusion. The perfusion approach shown here allows for the identification of compounds which interfere with gut motility in a highly sophisticated way. It is suitable for characterization of drug and dose specific changes in motility patterns and can be used in drug development and preclinical studies.

  7. Optic Disc Perfusion in Primary Open Angle and Normal Tension Glaucoma Eyes Using Optical Coherence Tomography-Based Microangiography

    PubMed Central

    Wen, Joanne C.; Zhang, Qinqin; Xin, Chen; Gupta, Divakar; Mudumbai, Raghu C.; Johnstone, Murray A.; Wang, Ruikang K.; Chen, Philip P.

    2016-01-01

    Purpose To investigate optic disc perfusion differences in normal, primary open-angle glaucoma (POAG), and normal tension glaucoma (NTG) eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. Design Cross-sectional, observational study. Subjects Twenty-eight normal, 30 POAG, and 31 NTG subjects. Methods One eye from each subject was scanned with a 68 kHz Cirrus HD-OCT 5,000-based OMAG prototype system centered at the optic nerve head (ONH) (Carl Zeiss Meditec Inc, Dublin, CA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. Main Outcome Measures Optic disc perfusion, quantified as flux, vessel area density, and normalized flux (flux normalized by the vessel area) within the ONH. Results Glaucomatous eyes had significantly lower optic disc perfusion in preLC in all three perfusion metrics (p<0.0001) compared to normal eyes. The visual field (VF) mean deviation (MD) and pattern standard deviation (PSD) were similar between the POAG and NTG groups, and no differences in optic disc perfusion were observed between POAG and NTG. Univariate analysis revealed significant correlation between optic disc perfusion and VF MD, VF PSD, and rim area in both POAG and NTG groups (p≤0.0288). However, normalized optic disc perfusion was correlated with some structural measures (retinal nerve fiber layer thickness and ONH cup/disc ratio) only in POAG eyes. Conclusions Optic disc perfusion detected with OMAG was significantly reduced in POAG and NTG groups compared to normal controls, but no difference was seen between POAG and NTG groups with similar levels of VF damage. Disc perfusion was significantly correlated with VF MD, VF PSD, and rim area in glaucomatous eyes. Vascular changes at the optic disc as measured using OMAG may provide useful information for

  8. Surgical repair of tricuspid valve leaflet tear following percutaneous closure of perimembranous ventricular septal defect using Amplatzer duct occluder I: Report of two cases

    PubMed Central

    Kuwelker, Saatchi Mahesh; Shetty, Devi Prasad; Dalvi, Bharat

    2017-01-01

    Tricuspid valve (TV) injury following transcatheter closure of perimembranous ventricular septal defect (PMVSD) with Amplatzer ductal occluder I (ADO I), requiring surgical repair, is rare. We report two cases of TV tear involving the anterior and septal leaflets following PMVSD closure using ADO I. In both the patients, the subvalvular apparatus remained unaffected. The patients presented with severe tricuspid regurgitation (TR) 6 weeks and 3 months following the device closure. They underwent surgical repair with patch augmentation of the TV leaflets. Postoperatively, both are asymptomatic with a mild residual TR. PMID:28163430

  9. Ruptured chordae tendineae of the posterior leaflet of the tricuspid valve as a cause of tricuspid regurgitation following blunt chest trauma.

    PubMed

    dos Santos, J; de Marchi, C H; Bestetti, R B; Corbucci, H A; Pavarino, P R

    2001-01-01

    A 12-year-old boy suffered a blunt chest trauma. Some hours later, a pulsatile bilateral jugular venous distension, a holosystolic murmur heard at the low parasternal border and hepatomegaly were observed. On echocardiography, ruptured chordae tendineae of the posterior leaflet of the tricuspid valve, as well as tricuspid regurgitation were detected. He remained asymptomatic during hospital stay and was discharged home in good condition. Thus, isolated ruptured chordae tendineae of the posterior leaflet of the tricuspid valve is another cause of tricuspid regurgitation following blunt chest trauma.

  10. Perfusion network shift during seizures in medial temporal lobe epilepsy.

    PubMed

    Sequeira, Karen M; Tabesh, Ali; Sainju, Rup K; DeSantis, Stacia M; Naselaris, Thomas; Joseph, Jane E; Ahlman, Mark A; Spicer, Kenneth M; Glazier, Steve S; Edwards, Jonathan C; Bonilha, Leonardo

    2013-01-01

    Medial temporal lobe epilepsy (MTLE) is associated with limbic atrophy involving the hippocampus, peri-hippocampal and extra-temporal structures. While MTLE is related to static structural limbic compromise, it is unknown whether the limbic system undergoes dynamic regional perfusion network alterations during seizures. In this study, we aimed to investigate state specific (i.e. ictal versus interictal) perfusional limbic networks in patients with MTLE. We studied clinical information and single photon emission computed tomography (SPECT) images obtained with intravenous infusion of the radioactive tracer Technetium- Tc 99 m Hexamethylpropyleneamine Oxime (Tc-99 m HMPAO) during ictal and interictal state confirmed by video-electroencephalography (VEEG) in 20 patients with unilateral MTLE (12 left and 8 right MTLE). Pair-wise voxel-based analyses were used to define global changes in tracer between states. Regional tracer uptake was calculated and state specific adjacency matrices were constructed based on regional correlation of uptake across subjects. Graph theoretical measures were applied to investigate global and regional state specific network reconfigurations. A significant increase in tracer uptake was observed during the ictal state in the medial temporal region, cerebellum, thalamus, insula and putamen. From network analyses, we observed a relative decreased correlation between the epileptogenic temporal region and remaining cortex during the interictal state, followed by a surge of cross-correlated perfusion in epileptogenic temporal-limbic structures during a seizure, corresponding to local network integration. These results suggest that MTLE is associated with a state specific perfusion and possibly functional organization consisting of a surge of limbic cross-correlated tracer uptake during a seizure, with a relative disconnection of the epileptogenic temporal lobe in the interictal period. This pattern of state specific shift in metabolic networks in

  11. A hybrid microsystem for parallel perfusion experiments on living cells

    NASA Astrophysics Data System (ADS)

    Greve, Frauke; Seemann, Livia; Hierlemann, Andreas; Lichtenberg, Jan

    2007-08-01

    A fully integrated microchip device for performing a complete and automated sample-perfusion experiment on living cells is presented. Cells were trapped and immobilized in a defined grid pattern inside a small 0.5 µl volume incubation chamber by pneumatic anchoring on 1000 5-µm orifices. This new cell trapping technique assures a precise and repeatable cell quantity for each experiment and enables the formation of a homogeneous cell population in the incubation chamber. The microsystem includes a perforated silicon chip seamlessly integrated by a new embedding technique in a larger elastomer substrate, which features the microfluidic network. The latter forms the incubation chamber and allows for economic logarithmic dilution of the sample reagent over a range of three orders of magnitude with subsequent perfusion of the cell population. First, the logarithmic dilution stage was validated using quantitative fluorescent imaging of fluorescein solution. Then, the cell adhesion and culturing inside the incubation chamber was studied using primary normal human dermal fibroblasts (NHDFs). The cells adhered well on laminin-coated surfaces and proliferated to form a confluent cell layer after 6 days in vitro. Finally, the complete system was tested by a perfusion experiment with cultured NHDFs, which were exposed to a fluorescent cell tracker at dilutions of 100 µm, 10 µm, 1 µm, 0.1 µm and 0 µm at a flow rate of 1.25 µl min-1 for 20 min. Fluorescence imaging of the cell array after incubation and image analysis showed a logarithmic relationship between sample concentration and the fluorescence signal. This paper describes the fabrication of the components and the assembly of the microsystem, the design approach and the validation of the sample diluter, cell-adhesion and cell-culturing experiments over several days.

  12. Myocardial perfusion scintigraphy: the evidence

    PubMed Central

    Anagnostopoulos, C.; Cerqueira, M.; Ell, P. J.; Flint, E. J.; Harbinson, M.; Kelion, A. D.; Al-Mohammad, A.; Prvulovich, E. M.; Shaw, L. J.; Tweddel, A. C.

    2003-01-01

    This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by

  13. Cardiac tissue engineering using perfusion bioreactor systems

    PubMed Central

    Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

    2009-01-01

    This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

  14. Myocardial perfusion analysis in cardiac computed tomography angiographic images at rest.

    PubMed

    Xiong, Guanglei; Kola, Deeksha; Heo, Ran; Elmore, Kimberly; Cho, Iksung; Min, James K

    2015-08-01

    Cardiac computed tomography angiography (CTA) is a non-invasive method for anatomic evaluation of coronary artery stenoses. However, CTA is prone to artifacts that reduce the diagnostic accuracy to identify stenoses. Further, CTA does not allow for determination of the physiologic significance of the visualized stenoses. In this paper, we propose a new system to determine the physiologic manifestation of coronary stenoses by assessment of myocardial perfusion from typically acquired CTA images at rest. As a first step, we develop an automated segmentation method to delineate the left ventricle. Both endocardium and epicardium are compactly modeled with subdivision surfaces and coupled by explicit thickness representation. After initialization with five anatomical landmarks, the model is adapted to a target image by deformation increments including control vertex displacements and thickness variations guided by trained AdaBoost classifiers, and regularized by a prior of deformation increments from principal component analysis (PCA). The evaluation using a 5-fold cross-validation demonstrates the overall segmentation error to be 1.00 ± 0.39 mm for endocardium and 1.06 ± 0.43 mm for epicardium, with a boundary contour alignment error of 2.79 ± 0.52. Based on our LV model, two types of myocardial perfusion analyzes have been performed. One is a perfusion network analysis, which explores the correlation (as network edges) pattern of perfusion between all pairs of myocardial segments (as network nodes) defined in AHA 17-segment model. We find perfusion network display different patterns in the normal and disease groups, as divided by whether significant coronary stenosis is present in quantitative coronary angiography (QCA). The other analysis is a clinical validation assessment of the ability of the developed algorithm to predict whether a patient has significant coronary stenosis when referenced to an invasive QCA ground truth standard. By training three machine

  15. Early brain perfusion improvement after ventriculoperitoneal shunt surgery in patients with idiopathic normal pressure hydrocephalus evaluated by 99mTc-HMPAO SPECT - preliminary report.

    PubMed

    Nocuń, Anna; Mosiewicz, Anna; Kaczmarczyk, Robert; Kazalska, Teresa; Czekajska-Chehab, Elżbieta; Chrapko, Beata; Trojanowski, Tomasz

    2015-01-01

    Idiopathic normal pressure hydrocephalus (iNPH) is a clinical syndrome that consists of the triad: gait disturbance, mental deterioration and urinary incontinence associated with normal cerebrospinal fluid pressure (CSF), without pre-existing abnormalities. The most popular treatment option is surgical implantation of a shunt. Brain perfusion increase occurring months or years after successful shunt surgery is well described in the literature. Early improvement of perfusion is not well documented. Therefore, the objective of the present study was to determine patterns of brain perfusion changes 3-6 days after the ventriculoperitoneal shunting in patients with iNPH by using 99mTc-HMPAO SPECT. Sixteen patients with iNPH (9 women, 7 men, mean age 64.1 ± 12.7 years) who underwent ventriculoperitoneal shunt surgery were included into the study group. Indications for implanting a shunt were based on clinical history, neuroimaging and CSF dynamic studies with an infusion test. Brain perfusion SPECT was performed 1-2 days before and 3-6 days after the surgical treatment. For comparison of perfusion before and after the surgery SPECT scans were assessed visually and semiquantitatively with voxel based analysis. No side effects were observed after the surgery. Brain perfusion improvement after shunting was observed in 10 patients (62.5%). Patterns of perfusion changes varied between patients, with combinations of different bilateral and lateralized brain regions involved. Perfusion increased in the whole brain (3 patients), in the right cerebral hemisphere (1 patient) or in the separate cerebral regions (6 patients): frontal, parietal, temporal, cerebellum, cingulate gyrus. Perfusion improvement was predominantly observed in the frontal lobes: right frontal (3 cases, 18.8%), left frontal (3 cases, 18.8%). Cerebral perfusion is recovered promptly after ventriculoperitoneal shunt surgery in about 60% of patients with iNPH. This improvement may be global or regional in

  16. Imaging of myocardial perfusion with magnetic resonance.

    PubMed

    Barkhausen, Jörg; Hunold, Peter; Jochims, Markus; Debatin, Jörg F

    2004-06-01

    Coronary artery disease (CAD) is currently the leading cause of death in developed nations. Reflecting the complexity of cardiac function and morphology, noninvasive diagnosis of CAD represents a major challenge for medical imaging. Although coronary artery stenoses can be depicted with magnetic resonance (MR) and computed tomography (CT) techniques, its functional or hemodynamic impact frequently remains elusive. Therefore, there is growing interest in other, target organ-specific parameters such as myocardial function at stress and first-pass myocardial perfusion imaging to assess myocardial blood flow. This review explores the pathophysiologic background, recent technical developments, and current clinical status of first-pass MR imaging (MRI) of myocardial perfusion.

  17. Distributions of perfusion and lung water.

    PubMed

    Ekeh, S U; Chu, R Y; Ficken, V J; Allen, E W; Ryals, C J

    1990-01-01

    We investigated the feasibility of using 123I-iodoantipyrine (123I-IAP) and 99mTc-labeled macroaggregated albumin (99mTc-MAA) to describe and compare the distributions of perfusion and water content in lung injuries. These radiopharmaceuticals were administered to 9 rabbits, 5 control and 4 with lung injuries. Isolated lungs were imaged by a scintillation gamma camera. The distribution of 123I-IAP outlined the entire lung mass whereas perfusion defect in the distribution of 99mTc-MAA was seen clearly in the case of severe lung injury.

  18. Stress-first Myocardial Perfusion Imaging.

    PubMed

    Hussain, Nasir; Parker, Matthew W; Henzlova, Milena J; Duvall, William Lane

    2016-02-01

    Stress-first approaches to myocardial perfusion imaging provide diagnostically and prognostically accurate perfusion data equivalent to a full rest-stress study, save time in the imaging laboratory, and reduce the radiation exposure to patients and laboratory staff. Converting a nuclear cardiology laboratory from a conventional rest-stress strategy to a stress-first approach involves challenges such as the need for attenuation correction, triage of patients to an appropriate protocol, real-time review of stress images, and consideration of differential reimbursement. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Clozapine may partially compensate for task-related brain perfusion abnormalities in risperidone-resistant schizophrenia patients.

    PubMed

    Molina, V; Tamayo, P; Montes, C; De Luxán, A; Martin, C; Rivas, N; Sancho, C; Domínguez-Gil, A

    2008-05-15

    Previous reports show different cerebral activity patterns during treatment with clozapine and typical neuroleptics. However, to date no study has directly compared the brain activity patterns while subjects are undergoing treatment with clozapine and other atypical antipsychotics. This comparison is of interest, given the probably different mechanism of action of clozapine in comparison with other atypicals. To assess the effect of clozapine on perfusion deviations still evident during treatment with risperidone. Here we used hexamethylene-propylenaminoxime single photon emission computed tomography to compare the perfusion patterns observed during the performance of a Stroop test in 10 patients sequentially treated with risperidone and clozapine, owing to a lack of response to the former, and in 10 healthy controls. Patients on risperidone showed decreased perfusion as compared to controls in the medial prefrontal, middle cingulate and insular regions, as well as increased activities in brain stem and the posterior hippocampus. After receiving clozapine, the same patients showed an even wider prefrontal perfusion deficit and the brain stem was still hyperactive, but the abnormalities in the cingulate cortex, insula and hippocampus had disappeared. Clinical improvement was directly related to an increase in thalamic perfusion. Clozapine may alleviate hyperactivity in the limbic system in schizophrenia and may facilitate activation of the regions involved in cognitive tasks to a greater degree than risperidone, as well as eliciting greater inhibition of the PF region.

  20. Metabolic Characteristics of Human Hearts Preserved for 12 Hours by Static Storage, Antegrade Perfusion or Retrograde Coronary Sinus Perfusion

    PubMed Central

    Cobert, Michael L.; Merritt, Matthew E.; West, LaShondra M.; Ayers, Colby; Jessen, Michael E.; Peltz, Matthias

    2014-01-01

    Objective(s) Machine perfusion of donor hearts is a promising strategy to increase the donor pool. Antegrade perfusion is effective but can lead to aortic valve incompetence and non-nutrient flow. Experience with retrograde coronary sinus perfusion of donor hearts has been limited. We tested the hypothesis that retrograde perfusion could support myocardial metabolism over an extended donor ischemic interval. Methods Human hearts from donors rejected or not offered for transplantation were preserved for 12 hours in University of Wisconsin Machine Perfusion Solution by: 1. Static hypothermic storage 2. Hypothermic antegrade machine perfusion or 3. Hypothermic retrograde machine perfusion. Myocardial oxygen consumption (MVO2), and lactate accumulation were measured. Ventricular tissue was collected for proton (1H) and phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) to evaluate the metabolic state of the myocardium. Myocardial water content was determined at end-experiment. Results Stable perfusion parameters were maintained throughout the perfusion period with both perfusion techniques. Lactate/alanine ratios were lower in perfused hearts compared to static hearts (p<.001). Lactate accumulation (Antegrade 2.0±.7, Retrograde 1.7±.1 mM) and MVO2 (Antegrade 0.25±.2, Retrograde 0.26±.3 mL O2/min/100g) were similar in machine perfused groups. High energy phosphates were better preserved in both perfused groups (p<.05). Left ventricular myocardial water content was increased in retrograde perfused (80.2±.8%) compared to both antegrade perfused (76.6±.8%, p=.02) and static storage hearts (76.7±1%, p=.02). Conclusions In conclusion, machine perfusion by either the antegrade or the retrograde technique can support myocardial metabolism over long intervals. Machine perfusion appears promising for long term preservation of human donor hearts. PMID:24642559

  1. Meta-Analysis of Stress Myocardial Perfusion Imaging

    ClinicalTrials.gov

    2017-06-06

    Coronary Disease; Echocardiography; Fractional Flow Reserve, Myocardial; Hemodynamics; Humans; Magnetic Resonance Imaging; Myocardial Perfusion Imaging; Perfusion; Predictive Value of Tests; Single Photon Emission Computed Tomography; Positron Emission Tomography; Multidetector Computed Tomography; Echocardiography, Stress; Coronary Angiography

  2. Blood leakage and melphalan leakage from the perfusion circuit during regional hyperthermic perfusion for malignant melanoma

    SciTech Connect

    Hafstroem, L.; Hugander, A.; Joensson, P.E.; Westling, H.; Ehrsson, H.

    1984-06-01

    In regional hyperthermic perfusion with melphalan for patients with malignant melanoma of the leg, plasma leakage between the perfusion circuit and the systemic circulation was 4-7 ml X min-1. The melphalan concentration in the perfusate was biphasic, with half-lives of 8-12 mins for the initial phase and 19-28 mins for the second phase, after the first dose. After a second dose, the corresponding values were 11-13 and 26-34 mins. The highest concentration in general circulation was 0.38 micrograms X ml-1.

  3. Effects of laser acupuncture on blood perfusion rate

    NASA Astrophysics Data System (ADS)

    Wang, Xian-ju; Zeng, Chang-chun; Liu, Han-ping; Liu, Song-hao; Liu, Liang-gang

    2006-09-01

    Based on Pennes equation, the influences of the intensity and the impulse frequency of laser acupuncture on the point tissues' blood flow perfusion rate are discussed. We find that the blood perfusion rate of point tissue increases with the intensity of laser acupuncture increasing. After impulse laser acupuncture the point tissue blood perfusion rate increase little, but after continuum laser acupuncture the point tissues blood perfusion rate increase much.

  4. Adaptation of the European Commission-recommended user testing method to patient medication information leaflets in Japan.

    PubMed

    Yamamoto, Michiko; Doi, Hirohisa; Yamamoto, Ken; Watanabe, Kazuhiro; Sato, Tsugumichi; Suka, Machi; Nakayama, Takeo; Sugimori, Hiroki

    2017-01-01

    The safe use of drugs relies on providing accurate drug information to patients. In Japan, patient leaflets called Drug Guide for Patients are officially available; however, their utility has never been verified. This is the first attempt to improve Drug Guide for Patients via user testing in Japan. To test and improve communication of drug information to minimize risk for patients via user testing of the current and revised versions of Drug Guide for Patients, and to demonstrate that this method is effective for improving Drug Guide for Patients in Japan. We prepared current and revised versions of the Drug Guide for Patients and performed user testing via semi-structured interviews with consumers to compare these versions for two guides for Mercazole and Strattera. We evenly divided 54 participants into two groups with similar distributions of sex, age, and literacy level to test the differing versions of the Mercazole guide. Another group of 30 participants were divided evenly to test the versions of the Strattera guide. After completing user testing, the participants evaluated both guides in terms of amount of information, readability, usefulness of information, and layout and appearance. Participants were also asked for their opinions on the leaflets. Response rates were 100% for both Mercazole and Strattera. The revised versions of both Guides were superior or equal to the current versions in terms of accessibility and understandability. The revised version of the Mercazole guide showed better ratings for readability, usefulness of information, and layout (p<0.01) than did the current version, while that for Strattera showed superior readability and layout (p<0.01). User testing was effective for evaluating the utility of Drug Guide for Patients. Additionally, the revised version had superior accessibility and understandability.

  5. 3D Xplane Echocardiographic Technique for Validation of Mitral Leaflet Separation to Assess Severity of Mitral Stenosis.

    PubMed

    Gokhroo, Rajendra K; Ranwa, Bhanwar L; Kishor, Kamal; Priti, Kumari; Avinash, Ananthraj; Gupta, Sajal; Bisht, Devendra

    2016-06-01

    Determining the severity of mitral stenosis (MS) is important for both prognostic and therapeutic implications. Mitral valve area (MVA) calculation techniques have more limitations. Mitral leaflet separation (MLS) is a precise and operator friendly alternative to planimetry. In contrast to previous researchers, we have used a novel 3D Xplane technique to validate MLS for assessing the severity of MS. 3D Xplane is superior for validation of MLS due to simultaneous real time acquisition of MLS in parasternal long-axis view and corresponding MVA by planimetry in parsternal short-axis view. It was a prospective observational single center study. A total of 174 patients with MS were evaluated for MVA estimation by various echocardiographic modalities. Maximum leaflet separation and corresponding planimetered MVA were measured using novel 3D Xplane technique. With 3D Xplane technique, there was strong positive correlation between planimetered MVA and MLS (R = 0.925, P < 0.001), irrespective of coexisting MR (R = 0.886, P < 0.001) or AF (R = 0.912, P < 0.001). Receiver operating characteristic curves of MLS demonstrated AUC for mild and severe MS to be 0.966 and 0.995, respectively. MLS less than 8.62 mm predicted severe MS with 95.5% sensitivity and 94.7% specificity and MLS more than 12.23 mm predicted mild MS with 93.2% sensitivity and 91.4% specificity. In our study, a strong correlation between planimetered MVA and MLS was found using 3D Xplane technique. 3D Xplane thus validates and standardizes MLS by excluding errors due to temporal and spatial variations which are important limitations of 2D echocardiography. © 2016, Wiley Periodicals, Inc.

  6. Time-dependent analysis of leaflets in mechanical aortic bileaflet heart valves in closing phase using the finite strip method.

    PubMed

    Mohammadi, H; Ahmadian, M T; Wan, W K

    2006-03-01

    Mechanical heart valves (MHV) are widely used to replace dysfunctional and failed heart valves. The bileaflet MHV design is very popular due to its superior hemodynamics. Since their introduction in 1977, the hemodynamics of bileaflet prostheses has been extensively studied. In this study the dynamic behaviour during the closing phase of a bileaflet MHV under normal physiological conditions has been investigated. Fluid analysis is based on the control volume with moving boundaries in the vicinity of the occluder. Unsteady continuity equation, unsteady momentum equation on the control volume and unsteady Bernoulli's equation have been used to calculate velocity of blood flow and force on the occluder tip. To solve the governing equations for the calculation of pressure and the related force, the finite strips method has been implemented. Only 32 strips are sufficient to calculate the force due to pressure on the leaflets. The equations of motion have been solved using the Runge-Kutta method in the fourth order. The maximum velocity of the leakage flow in the closing phase falls within the range of 3.5-4.4 m/s. The maximum velocity of the occluder tip is in the range of 2.4-3.2 m/s. The backflow also exhibits oscillation similar to that of the occluder with net backflow rate in the range of 9.7-12.3 ml/beat. The impact force between occluder and its housing is in the range of 80-140 N and impact occurs during 33.1-41.0 ms and the leaflets are completely settled at 108-115 ms in the closing phase. The finite strip method was implemented to study the closing phase of a bileaflet MHV. Results are consistent with the previous experimental data. This method is of general applicability to study dynamic behaviour of MHVs.

  7. Serum HSP27 is associated with medullary perfusion in kidney allografts

    PubMed Central

    Marquez, Eva; Sadowski, Elizabeth; Reese, Shannon; Vidyasagar, Aparna; Artz, Nathan; Fain, Sean; Jacobson, Lynn; Swain, William; Djamali, Arjang

    2015-01-01

    Background Heat shock protein 27 (HSP27) is a small HSP up-regulated in response to stress in the kidney. The relationship between HSP27 and intrarenal oxygenation in patients with native and transplant kidney disease is unknown. Methods We compared HSP27 levels, intrarenal oxygenation measured by blood oxygen-level dependent (BOLD) imaging using R2* values, and perfusion determined by arterial spin labeling (ASL) magnetic resonance imaging (MRI), between patients with native and transplant kidney disease (n=28). Results There were no statistical differences in mean age (53.9 vs. 47.1 years), kidney function (63.6 vs. 50.7 ml/min per 1.73 m2), mean arterial blood pressure (91.6 vs. 91.1 mm Hg), hematocrit (40.6% vs. 39.3%), diuretic or angiotensin-converting enzyme inhibitor use, serum or urine levels of hydrogen peroxide, nitric oxide, F2 isoprostanes and HSP27 between native and transplant kidneys. BOLD-MRI studies demonstrated comparable patterns in intrarenal oxygen bioavailability (medullary R2* 18.1 vs. 18.3/s and cortical R2* 12 vs. 11.7/s, respectively). However, medullary perfusion was significantly lower in transplant kidneys (36.4 vs. 78.7 ml/100 g per minute, p=0.0002). There was a linear relationship between serum HSP27 concentrations and medullary perfusion in kidney allografts (HSP27 concentration [ng/mL] = 0.78 + 0.09 medullary perfusion, R2=0.43, p=0.01). Conclusions Our study demonstrates that medullary perfusion is significantly lower in kidney allografts compared with native kidneys with comparable renal function. We further noted a direct association between serum HSP27 levels and medullary perfusion after transplantation. Additional studies are needed to examine the role of HSP27 as a biomarker of kidney disease progression. PMID:22383348

  8. Effect of Perfusion Fluids on Recovery of Inflammatory Mediators in Microdialysis.

    PubMed

    Khan, F; Pharo, A; Lindstad, J K; Mollnes, T E; Tønnessen, T I; Pischke, S E

    2015-11-01

    Microdialysis is an excellent tool to assess tissue inflammation in patients, but in vitro systems to evaluate recovery of inflammatory mediators have not been standardized. We aimed to develop a reference plasma preparation and evaluate different perfusion fluids with respect to recovery of metabolic and inflammatory markers. The reference preparation was produced by incubation of human blood with lipopolysaccharide and cobra venom factor to generate cytokines and activate complement, respectively. Microdialysis with 100 kDa catheters was performed using different colloid and crystalloid perfusion fluids (hydroxyethyl starch (HES) 130/0.4, HES 200/0.5, hyperosmolar HES 200/0.5, albumin 200 g/l, T1 perfusion fluid and Ringer's acetate) compared to today's recommended dextran 60 solution. Recovery of glucose, glycerol and pyruvate was not significantly different between the perfusion fluids, whereas lactate had lower recovery in HES 200/0.5 and albumin perfusion fluids. Recovery rates for the inflammatory proteins in comparison with the concentration in the reference preparation differed substantially: IL-6 = 9%, IL-1β = 18%, TNF = 0.3%, MCP-1 = 45%, IL-8 = 48%, MIG = 48%, IP-10 = 25%, C3a = 53% and C5a = 12%. IL-10 was not detectable in microdialysis dialysate. HES 130/0.4 and HES 200/0.5 yielded a recovery not significantly different from dextran 60. Hyperosmolar HES 200/0.5 and albumin showed significantly different pattern of recovery with increased concentration of MIG, IP-10, C3a and C5a and decreased concentration of IL-1β, TNF, MCP-1 and IL-8 in comparison with dextran 60. In conclusion, microdialysis perfusion fluid dextran 60 can be replaced by the commonly used HES 130/0.4, whereas albumin might be used if specific immunological variables are in focus. The present reference plasma preparation is suitable for in vitro evaluation of microdialysis systems. © 2015 The Foundation for the Scandinavian Journal of Immunology.

  9. Isoattenuating insulinomas at biphasic contrast-enhanced CT: frequency, clinicopathologic features and perfusion characteristics.

    PubMed

    Zhu, Liang; Xue, Hua-Dan; Sun, Hao; Wang, Xuan; He, Yong-Lan; Jin, Zheng-Yu; Zhao, Yu-Pei

    2016-10-01

    We aimed to determine the frequency of isoattenuating insulinomas, to investigate their clinicopathological features and to assess their regional pancreatic perfusion characteristics. Institutional review board approval was obtained, and patient informed consent was waived. From July 2010 to June 2014, 170 patients (66 male, 104 female) with endogenous hyperinsulinemic hypoglycemia underwent biphasic contrast-enhanced CT before surgery, and 129 of those patients also received preoperative whole-pancreas CT perfusion. A total of 181 tumours were proved histopathologically after surgery. Enhancement pattern and regional pancreatic perfusion characteristics were analyzed. Clinical features, tumour size and pathological grading were investigated. The frequency of isoattenuating tumours was 24.9 %. Tumour size and WHO grading was not significantly different between isoattenuating and hyperattenuating tumours. Tumour-free regions had identical blood flow (BF) regardless of their location (p = 0.35). Isoattenuating tumour-harbouring regions had lower BF compared with hyperattenuating tumour-harbouring regions; both showed higher BF compared with tumour-free neighbourhood regions (all p < 0.01). For patients with isoattenuating tumours, the overall hospital stay was longer (p < 0.01). A substantial subset of insulinomas were isoattenuating on biphasic CT. CT perfusion showed higher BF in tumour-harbouring regions compared to tumour-free regions, providing a clue for tumour regionalization. • About a quarter of all insulinomas were isoattenuating on biphasic contrast-enhanced CT. • CT perfusion finds tumour-harbouring regions have higher blood-flow compared to tumour-free regions. • CT perfusion provides important information for tumour regionalization, for isoattenuating tumours.

  10. Role of hypothermic machine perfusion in liver transplantation.

    PubMed

    Schlegel, Andrea; Dutkowski, Philipp

    2015-06-01

    Machine liver perfusion has significantly evolved during the last ten years to optimize extended criteria liver grafts and to address the worldwide organ shortage. This review gives an overview on available ex vivo and in vivo data on hypothermic machine liver perfusion. We discuss also possible protective pathways and show most recent clinical applications of hypothermic machine liver perfusion in human.

  11. Perfusion MRI: The Five Most Frequently Asked Clinical Questions

    PubMed Central

    Essig, Marco; Nguyen, Thanh Binh; Shiroishi, Mark S.; Saake, Marc; Provenzale, James M.; Enterline, David S.; Anzalone, Nicoletta; Dörfler, Arnd; Rovira, Àlex; Wintermark, Max; Law, Meng

    2013-01-01

    OBJECTIVE This article addresses questions that radiologists frequently ask when planning, performing, processing, and interpreting MRI perfusion studies in CNS imaging. CONCLUSION Perfusion MRI is a promising tool in assessing stroke, brain tumors, and neurodegenerative diseases. Most of the impediments that have limited the use of perfusion MRI can be overcome to allow integration of these methods into modern neuroimaging protocols. PMID:23971482

  12. Increased sinusoidal volume and solute extraction during retrograde liver perfusion

    SciTech Connect

    Bass, N.M.; Manning, J.A.; Weisiger, R.A.

    1989-06-01

    Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of (/sup 14/C)sucrose washout during perfusion as well as by direct measurement of (/sup 14/C)sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the (/sup 14/C)sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver.

  13. An alternative method for neonatal cerebro-myocardial perfusion

    PubMed Central

    Luciani, Giovanni Battista; De Rita, Fabrizio; Faggian, Giuseppe; Mazzucco, Alessandro

    2012-01-01

    Several techniques have already been described for selective cerebral perfusion during repair of aortic arch pathology in children. One method combining cerebral with myocardial perfusion has also been proposed. A novel technique is reported here for selective and independent cerebro-myocardial perfusion for neonatal and infant arch surgery. Technical aspects and potential advantages are discussed. PMID:22307393

  14. Fully automatic segmentation of the mitral leaflets in 3D transesophageal echocardiographic images using multi-atlas joint label fusion and deformable medial modeling.

    PubMed

    Pouch, A M; Wang, H; Takabe, M; Jackson, B M; Gorman, J H; Gorman, R C; Yushkevich, P A; Sehgal, C M

    2014-01-01

    Comprehensive visual and quantitative analysis of in vivo human mitral valve morphology is central to the diagnosis and surgical treatment of mitral valve disease. Real-time 3D transesophageal echocardiography (3D TEE) is a practical, highly informative imaging modality for examining the mitral valve in a clinical setting. To facilitate visual and quantitative 3D TEE image analysis, we describe a fully automated method for segmenting the mitral leaflets in 3D TEE image data. The algorithm integrates complementary probabilistic segmentation and shape modeling techniques (multi-atlas joint label fusion and deformable modeling with continuous medial representation) to automatically generate 3D geometric models of the mitral leaflets from 3D TEE image data. These models are unique in that they establish a shape-based coordinate system on the valves of different subjects and represent the leaflets volumetrically, as structures with locally varying thickness. In this work, expert image analysis is the gold standard for evaluating automatic segmentation. Without any user interaction, we demonstrate that the automatic segmentation method accurately captures patient-specific leaflet geometry at both systole and diastole in 3D TEE data acquired from a mixed population of subjects with normal valve morphology and mitral valve disease. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Temperature shift experiments suggest that metabolic impairment and enhanced rates of photorespiration decrease organic acid levels in soybean leaflets exposed to supra-optimal growth temperatures

    USDA-ARS?s Scientific Manuscript database

    Citrate, malate, malonate, fumarate and succinate in soybean leaflets decreased 40 to 80% when plants were grown continuously in controlled environment chambers at 36/28 compared to 28/20 °C. Glycerate was not temperature responsive in this study. Temperature effects on the above mentioned organi...

  16. Sequential hydrophile and lipophile solubilization as an efficient method for decellularization of porcine aortic valve leaflets: structure, mechanical property and biocompatibility study.

    PubMed

    Qiao, Wei-Hua; Liu, Peng; Hu, Dan; Al Shirbini, Mahmoud; Zhou, Xian-Ming; Dong, Nian-Guo

    2016-12-13

    Antigenicity of xenogeneic tissues is the major obstacle to increased utilization of these materials in clinical medicine. Residual xenoantigens in decellularized tissue elicit the immune response after implantation, causing graft failure. With this in mind, we proposed the potential use of three protein solubilization-based protocols for porcine aortic valve leaflets decellularization. We demonstrated that hydrophile solubilization alone (HSA) achieved incomplete decellularization; lipophile solubilization alone (LSA) completely removed all cells and two most critical xenoantigens, galactose-α(1,3)-galactose (α-Gal) and major histocompatibility complex I (MHC I), but caused severe alterations of the structure and mechanical properties; sequential hydrophile and lipophile solubilization (SHLS) resulted in a complete removal of cells, α-Gal and MHC I, and a well preservation of the structure and mechanical properties; in contrast, a previously reported method using Triton X-100, sodium deoxycholate and IGEPAL CA-630 (TSI) resulted in a complete removal of all cells and MHC I, but with remaining α-Gal epitope. Moreover, LSA- and SHLS-treated leaflets showed significantly reduced leucocyte activation (polymorphonuclear elastase) upon interaction with human blood in vitro. When implanted subdermally in rats for 6 weeks, LSA- or SHLS-treated leaflets were presented with more biocompatible implants and all four decellularized leaflets were highly resistant to calcification. These findings illustrated that the SHLS protocol could be considered as a promising decellularization method for the decellularization of xenogeneic tissues in tissue engineering and regenerative medicine.

  17. Visual assessment of magnetic resonance imaging perfusion lesions in a large patient group.

    PubMed

    Siemonsen, S; Fitting, T; Thomalla, G; Krützelmann, A; Fiehler, J

    2012-12-01

    Few magnetic resonance imaging (MRI) studies of stroke have evaluated the value of visual assessment of perfusion/diffusion mismatch, which is crucial for routine application. In this study an attempt was made to visually assess perfusion lesions resembling the acute clinical situation and identify parameters with the highest interobserver reliability when used to define a perfusion/diffusion mismatch and the highest accuracy for prediction of infarct growth. Magnetic resonance imaging was performed within 6 h of symptom onset and again 1-11 days thereafter in 86 consecutive stroke patients who received intravenous thrombolytic therapy. The MRI protocol included diffusion-weighted imaging apparent diffusion coefficient (DWI/ADC), fluid-attenuated inversion recovery (FLAIR) and perfusion imaging (PI). Maps for different perfusion parameters, e.g. cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) and time to peak (TTP) were calculated. Areas of perfusion deficits of all perfusion parameters were visually compared to corresponding ADCs and final infarct size by two independent observers. The final infarct size was overestimated by TTP (in 81/83 patients by raters 1 and 2, respectively), MTT (82/83) and CBF (65/74) lesions. The ADC lesions were rated smaller than the final infarct size in 43/38 cases by raters 1 and 2 and the CBV decrease was rated to underestimate final infarct size in 40/31 cases. The only significantly increased OR of 3.883 (95 % CI 1.466-10.819, p = 0.004, rater 1)/5.142 (95 % CI 1.828-15.142, p = 0.001, rater 2) for predicting infarct growth was observed for the presence of a CBV > ADC mismatch, which also showed the highest kappa value of 0.407. All mismatch patterns were prone to high interrater variability when assessed under conditions resembling the clinical setting. Of all tested mismatch patterns the CBV > ADC mismatch was the strongest predictor of lesion growth while visual assessment of TTP and CBF generally

  18. Lung Perfusion Scanning in Hepatic Cirrhosis

    PubMed Central

    Stanley, N. N.; Ackrill, P.; Wood, J.

    1972-01-01

    Abnormal lung perfusion scans using radioactive particles were found in five out of six cases of hepatic cirrhosis with arterial hypoxaemia. None had clinical evidence of cardiopulmonary disease or signs of pulmonary embolism on arteriography. The scan defects are probably caused by a disorder of the pulmonary microvasculature, which may show regional variation in severity. ImagesFIG. 1FIG. 2 PMID:4645896

  19. A reappraisal of retrograde cerebral perfusion

    PubMed Central

    2013-01-01

    Brain protection during aortic arch surgery by perfusing cold oxygenated blood into the superior vena cava was first reported by Lemole et al. In 1990 Ueda and associates first described the routine use of continuous retrograde cerebral perfusion (RCP) in thoracic aortic surgery for the purpose of cerebral protection during the interval of obligatory interruption of anterograde cerebral flow. The beneficial effects of RCP may be its ability to sustain brain hypothermia during hypothermic circulatory arrest (HCA) and removal of embolic material from the arterial circulation of the brain. RCP can offer effective brain protection during HCA for about 40 to 60 minutes. Animal experiments revealed that RCP provided inadequate cerebral perfusion and that neurological recovery was improved with selective antegrade cerebral perfusion (ACP), however, both RCP and ACP provide comparable clinical outcomes regarding both the mortality and stroke rates by risk-adjusted and case-matched comparative study. RCP still remains a valuable adjunct for brain protection during aortic arch repair in particular pathologies and patients. PMID:23977600

  20. Asynchronicity of facial blood perfusion in migraine.

    PubMed

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A; Kamshilin, Alexei A; Närhi, Matti; Karjalainen, Pasi A; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.