Sample records for leaflets evoke distinct
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Fay, J P; Cheng, K J; Hanna, M R; Howarth, R E; Costerton, J W
1981-04-01
A newly developed technique using ruthenium red to detect foci of bacterial digestion in mounts of whole leaflets that had been incubated with rumen bacteria was used to compare the digestion of alfalfa, a bloat-causing legume, and sainfoin, a bloat-safe legume. When whole leaflets were suspended in an artificial rumen medium and inoculated with rumen bacteria, massive bacterial adhesion and proliferation were noted at the stomata of alfalfa leaflets after 6 h of incubation, whereas only a few isolated bacteria adhered near the stomata of sainfoin leaflets After 22 h of incubation, the epidermal layers of alfalfa leaflets had peeled away in many areas, revealing an extensive bacterial invasion of the underlying mesophyll tissue in which large bacterial microcolonies had formed in intercellular spaces, and in intracellular spaces in several areas where plant cell walls had broken down. After 22 h of incubation, the surface of sainfoin leaflets resembled that of alfalfa leaflets at 6 h, with bacterial microcolonies adhering to the area surrounding the stomata, but without sloughing of the epidermis. Uninoculated control leaflets of both species showed no surface alteration but part of their normal bacterial flora had proliferated to form microcolonies on the surface after 22 h incubation. Dry matter loss due to leaching or bacterial digestion when whole leaflets of legumes were suspended in an artificial rumen medium, alone or with rumen bacteria, was significantly higher in the bloat-causing group. Values of leaching and of bacterial digestion were positively correlated. We conclude that reported differences in plant anatomy, and in cell wall chemistry, produce distinct rates or organic nutrient release from legume leaflets, and that these same differences produce an equally distinct susceptibility of leaflets to bacterial invasion, plant cell rupture, and the consequent release of intracellular plant components. The rate of release of organic nutrients from legume leaflets may be important in the etiology of foamy pasture bloat. This technique of in vitro digestion of whole leaflets followed by ruthenium red staining shows some promise of providing a rapid and qualitative test to distinguish, within a species, cultivars that may differ in their bloat-related characteristics.
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Transapical endovascular implantation of neochordae using a suction and suture device.
Maisano, Francesco; Michev, Iassen; Rowe, Stanton; Addis, Alessandro; Campagnol, Marino; Guidotti, Andrea; Colombo, Antonio; Alfieri, Ottavio
2009-07-01
Neochordae implantation is a standard method for treatment of mitral valve prolapse. We describe a transcatheter technology enabling transapical endovascular chordal implantation. Six adult pigs were anesthetized. Two 10F sheaths were introduced in the femoral vessels for monitoring and intracardiac echo. After midline sternotomy, the pericardium was opened, the apex was punctured inside two 2-0 polypropylene purse strings. A 0.035 in J tipped guidewire was introduced in the left ventricle and an ultra stiff 14F sheath (guide catheter) inserted through the apex. A suction-and-suture device was introduced in the left ventricle. The mitral valve was crossed under echo guidance. Using suction, either the anterior (two cases) or posterior (four cases) leaflet was captured and a loop of 4-0 polypropylene was thrown at the edge of the leaflet. The loop, with a pledget, was exteriorized through the introducer. The introducer was removed and the purse-string tied. Under echo guidance, the neochordae suture was pulled and tied over a pledget to evoke leaflet tethering. The animals were sacrificed and gross anatomy reviewed. Leaflet capture was feasible in the intended location in all cases. Following suture tethering, variable degrees of MR were obtained. At gross anatomy, the neochordae were positioned at 1-4mm from the leaflet free edge, and were firmly attached to the leaflets. Transcatheter endovascular neochordae implantation is feasible. A prolapse model is needed to further demonstrate feasibility under pathologic conditions. The apical approach allows easy and direct route to transcatheter beating heart minimally invasive mitral repair.
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Pregnancy-induced remodeling of heart valves.
Pierlot, Caitlin M; Moeller, Andrew D; Lee, J Michael; Wells, Sarah M
2015-11-01
Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves. Copyright © 2015 the American Physiological Society.
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Carpenter, Timothy S.; Parkin, Jamie; Khalid, Syma
2016-08-12
Permeation of small molecules across cell membranes is a ubiquitous process in biology and is dependent on the principles of physical chemistry at the molecular level. Here we use atomistic molecular dynamics simulations to calculate the free energy of permeation of a range of small molecules through a model of the outer membrane of Escherichia coli, an archetypical Gram-negative bacterium. The model membrane contains lipopolysaccharide (LPS) molecules in the outer leaflet and phospholipids in the inner leaflet. Our results show that the energetic barriers to permeation through the two leaflets of the membrane are distinctly asymmetric; the LPS headgroups providemore » a less energetically favorable environment for organic compounds than do phospholipids. In summary, we provide the first reported estimates of the relative free energies associated with the different chemical environments experienced by solutes as they attempt to cross the outer membrane of a Gram-negative bacterium. Furthermore, these results provide key insights for the development of novel antibiotics that target these bacteria.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Carpenter, Timothy S.; Parkin, Jamie; Khalid, Syma
Permeation of small molecules across cell membranes is a ubiquitous process in biology and is dependent on the principles of physical chemistry at the molecular level. Here we use atomistic molecular dynamics simulations to calculate the free energy of permeation of a range of small molecules through a model of the outer membrane of Escherichia coli, an archetypical Gram-negative bacterium. The model membrane contains lipopolysaccharide (LPS) molecules in the outer leaflet and phospholipids in the inner leaflet. Our results show that the energetic barriers to permeation through the two leaflets of the membrane are distinctly asymmetric; the LPS headgroups providemore » a less energetically favorable environment for organic compounds than do phospholipids. In summary, we provide the first reported estimates of the relative free energies associated with the different chemical environments experienced by solutes as they attempt to cross the outer membrane of a Gram-negative bacterium. Furthermore, these results provide key insights for the development of novel antibiotics that target these bacteria.« less
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Snider, John L; Choinski, John S; Wise, Robert R
2009-05-01
We sought to test the hypothesis that stomatal development determines the timing of gas exchange competency, which then influences leaf temperature through transpirationally driven leaf cooling. To test this idea, daily patterns of gas exchange and leaflet temperature were obtained from leaves of two distinctively different developmental stages of smooth sumac (Rhus glabra) grown in its native habitat. Juvenile and mature leaves were also sampled for ultrastructural studies of stomatal development. When plants were sampled in May-June, the hypothesis was supported: juvenile leaflets were (for part of the day) from 1.4 to 6.0 degrees C warmer than mature leaflets and as much as 2.0 degrees C above ambient air temperature with lower stomatal conductance and photosynthetic rates than mature leaflets. When measurements were taken from July to October, no significant differences were observed, although mature leaflet gas exchange rates declined to the levels of the juvenile leaves. The gas exchange data were supported by the observations that juvenile leaves had approximately half the number of functional stomata on a leaf surface area basis as did mature leaves. It was concluded that leaf temperature and stage of leaf development in sumac are strongly linked with the higher surface temperatures observed in juvenile leaflets in the early spring possibly being involved in promoting photosynthesis and leaf expansion when air temperatures are cooler.
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NASA Astrophysics Data System (ADS)
Juchum, Fabrício Sacramento; Costa, Marco Antônio; Amorim, André Márcio; Corrêa, Ronan Xavier
2008-11-01
Caesalpinia echinata (brazilwood or Pernambuco wood) comprises a complex of three morphological leaf variants, characterized by differences in the number and size of the pinnae and leaflets, and occurring in allopatric and sympatric populations. The present study evaluates the utility of the chloroplast DNA trnL intron in a phylogenetic analysis of the three leaf variants along with other species of Caesalpinia and generic relatives. Our study supports the hypothesis that the name C. echinata designates a species complex and provides evidence that one of the forms, the highly divergent C. echinata large-leafleted variant, represents a distinct taxon.
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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.
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Sreenivasan, Varun; Kyriakatos, Alexandros; Mateo, Celine; Jaeger, Dieter; Petersen, Carl C.H.
2016-01-01
Abstract. The spatial organization of mouse frontal cortex is poorly understood. Here, we used voltage-sensitive dye to image electrical activity in the dorsal cortex of awake head-restrained mice. Whisker-deflection evoked the earliest sensory response in a localized region of primary somatosensory cortex and visual stimulation evoked the earliest responses in a localized region of primary visual cortex. Over the next milliseconds, the initial sensory response spread within the respective primary sensory cortex and into the surrounding higher order sensory cortices. In addition, secondary hotspots in the frontal cortex were evoked by whisker and visual stimulation, with the frontal hotspot for whisker deflection being more anterior and lateral compared to the frontal hotspot evoked by visual stimulation. Investigating axonal projections, we found that the somatosensory whisker cortex and the visual cortex directly innervated frontal cortex, with visual cortex axons innervating a region medial and posterior to the innervation from somatosensory cortex, consistent with the location of sensory responses in frontal cortex. In turn, the axonal outputs of these two frontal cortical areas innervate distinct regions of striatum, superior colliculus, and brainstem. Sensory input, therefore, appears to map onto modality-specific regions of frontal cortex, perhaps participating in distinct sensorimotor transformations, and directing distinct motor outputs. PMID:27921067
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Rapid Recycling of Ca2+ between IP3-Sensitive Stores and Lysosomes
López Sanjurjo, Cristina I.; Tovey, Stephen C.; Taylor, Colin W.
2014-01-01
Inositol 1,4,5-trisphosphate (IP3) evokes release of Ca2+ from the endoplasmic reticulum (ER), but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK) cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH) evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM) to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways. PMID:25337829
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Rapid recycling of Ca2+ between IP3-sensitive stores and lysosomes.
López Sanjurjo, Cristina I; Tovey, Stephen C; Taylor, Colin W
2014-01-01
Inositol 1,4,5-trisphosphate (IP3) evokes release of Ca2+ from the endoplasmic reticulum (ER), but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK) cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH) evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM) to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways.
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Sousa-Baena, Mariane Silveira; Lohmann, Lúcia G; Rossi, Magdalena; Sinha, Neelima R
2014-02-01
Leaves have undergone structural modifications over evolutionary time, and presently exist in many forms. For instance, in Fabaceae and Bignoniaceae, leaf parts can be modified into tendrils. Currently, no data are available on genic control of tendrilled leaf development outside Fabaceae. Here, we conducted a detailed study of three representatives of Bignonieae: Amphilophium buccinatorium, Dolichandra unguis-cati, and Bignonia callistegioides, bearing multifid, trifid, and simple-tendrilled leaves, respectively. We investigated the structure of their petioles, petiolules, leaflets, and tendrils through histological analyses. Additionally, the expression of SHOOTMERISTEMLESS (STM), PHANTASTICA (PHAN), and LEAFY/FLORICAULA (LFY/FLO) during leaf development was analyzed by in situ hybridizations. Tendrils share some anatomical similarities with leaflets, but not with other leaf parts. Transcripts of both STM and LFY/FLO were detected in leaf primordia, associated with regions from which leaflets and tendril branches originate. PHAN expression was found to be polarized in branched tendrils, but not in simple tendrils. In Bignonieae, tendrils are modified leaflets that, as a result of premature completion of development, become bladeless organs. Bignonieae leaves develop differently from those of peas, as both LFY/FLO and STM are expressed in developing leaves of Bignonieae. Moreover, PHAN is probably involved in tendril diversification in Bignonieae, as it has distinct expression patterns in different leaf types. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.
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Odelin, Gaëlle; Faure, Emilie; Coulpier, Fanny; Di Bonito, Maria; Bajolle, Fanny; Studer, Michèle; Avierinos, Jean-François; Charnay, Patrick; Topilko, Piotr; Zaffran, Stéphane
2018-01-03
Although cardiac neural crest cells are required at early stages of arterial valve development, their contribution during valvular leaflet maturation remains poorly understood. Here, we show in mouse that neural crest cells from pre-otic and post-otic regions make distinct contributions to the arterial valve leaflets. Genetic fate-mapping analysis of Krox20-expressing neural crest cells shows a large contribution to the borders and the interleaflet triangles of the arterial valves. Loss of Krox20 function results in hyperplastic aortic valve and partially penetrant bicuspid aortic valve formation. Similar defects are observed in neural crest Krox20 -deficient embryos. Genetic lineage tracing in Krox20 -/- mutant mice shows that endothelial-derived cells are normal, whereas neural crest-derived cells are abnormally increased in number and misplaced in the valve leaflets. In contrast, genetic ablation of Krox20 -expressing cells is not sufficient to cause an aortic valve defect, suggesting that adjacent cells can compensate this depletion. Our findings demonstrate a crucial role for Krox20 in arterial valve development and reveal that an excess of neural crest cells may be associated with bicuspid aortic valve. © 2018. Published by The Company of Biologists Ltd.
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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 two techniques indicates that under acute conditions, use of artificial neochordae or native chordal translocations have similar benefits. PMID:23291143
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Doctors and pharmacists provision and opinions of medicines information leaflets in New Zealand.
Young, Amber; Tordoff, June; Leitch, Sharon; Smith, Alesha
2018-06-01
Background Providing verbal medicines information to patients may be insufficient. Providing medicine information leaflets could support verbal information, however New Zealand health professionals' opinions or use of leaflets is unknown. Objective To examine self-reported provision and health professionals' views about medicine information leaflets and to determine their support for tailoring patient leaflets. Setting A cross sectional survey of general practitioners (GPs) and community pharmacists in New Zealand primary care. Method GPs and pharmacists completed validated questionnaires. Data was collected using SurveyMonkey® and where applicable, Chi squared analysis was carried out. Main outcome measures Frequency of leaflet provision, how leaflets are used in practice and why, likes and dislikes of available leaflets, and opinions on providing tailored information. Results 143 GPs and 126 pharmacists responded. For new medicines, significantly more pharmacists than GPs reported providing leaflets all or most of the time. For repeat medicines, leaflets were more likely to be given only on request. Leaflets were given to ensure patients are well-informed. Most GPs and pharmacists report discussing sections of leaflets with patients. The likes and dislikes of leaflets were mostly about design and content. Both professions support tailoring leaflets to meet individual's requirements. Conclusions Provision of medicines information needs to be re-evaluated. Relying on verbal communication is inadequate and leaflet provision appears to be suboptimal. Making leaflets more patient-centred and accessible could improve health professionals' perceptions and use of them. Automated creation and provision of tailored summary leaflets would be beneficial. Further advantage could be gained by digital patient access.
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Chang, Y; Tsai, C C; Liang, H C; Sung, H W
2001-12-01
This study was designed to evaluate a newly developed biologic valved conduit fixed with genipin used to reconstruct the right ventricular outflow tract in a canine model. Fresh bovine jugular veins with a retained native valve procured from a slaughterhouse were used as raw materials to fabricate the valved conduits. A naturally occurring crosslinking agent, genipin, was used to fix the procured jugular veins. The glutaraldehyde-fixed counterpart was used as a control. A canine model was used in the study. Echocardiography revealed that the motion of the valvular leaflets in both the glutaraldehyde- and genipin-fixed conduits was satisfactory. The transvalvular pressure gradients of both studied groups were minimal. No endothelium-like cells were observed on the luminal surface of the conduit and the valvular leaflet for the glutaraldehyde-fixed group throughout the entire course of the study. In contrast, endothelium-like cells were observed on the entire surface of the genipin-fixed valved conduit retrieved at 6 months postoperatively in all the cases studied. There was no evidence of luminal fibrous peel in any the valved conduits studied. Degradation of valvular leaflet in one of the glutaraldehyde-fixed conduits was observed. In this particular case, thrombus formation was also observed on the surface of the valvular leaflet. On the other hand, no apparent degradation or thrombus formation was observed on the surfaces of the genipin-fixed valvular leaflet and conduit. A significantly more severe inflammatory reaction was observed for the glutaraldehyde-fixed conduit than for its genipin-fixed counterpart throughout the entire course of the study. The calcium contents of the samples before implantation and those retrieved at distinct implantation duration were minimal for both the glutaraldehyde- and genipin-fixed tissues. Although further studies are necessary, the genipin-fixed valved conduit appears to have great potential in helping mitigate the complications observed in the commercially available conduits.
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Medicine information leaflets for non-steroidal anti-inflammatory drugs in Thailand.
Phueanpinit, Pacharaporn; Pongwecharak, Juraporn; Krska, Janet; Jarernsiripornkul, Narumol
2016-02-01
The importance of promoting the use of patient-oriented medicines leaflets is recognized in many countries. Leaflets should include basic information plus specific warnings, and be provided with all medicines, but there is little attempt at enforcement of these requirements in Thailand. To determine content and availability of Thai information leaflets for nonsteroidal anti-inflammatory drugs (NSAIDs). Leaflets for all NSAIDs available for purchase from 34 pharmacies in a large city were evaluated against a checklist and number of leaflets assessed against number of medicine packs available in each pharmacy. Of the 76 leaflets for ten different NSAIDs, 67 (88 %) were for locally manufactured products. Only 22 % of 76 leaflets were sufficient in number for distribution with medicines, while only 4 % had patient-oriented leaflets. No leaflet covered all topics in the checklist. Less than half included safety information, such as contraindications (46 %), precautions (47 %), and adverse drug reactions (34 %). Locally-produced leaflets provided less information than those for originator products and no leaflet included all the warnings required by Thai regulations. This study illustrates the variable availability and quality of NSAID information leaflets. The lack of accessible essential information about medicines in Thailand requires urgent attention to enable patients to minimise adverse reactions.
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Sritharan, Deepa; Fathi, Parinaz; Weaver, Jason D; Retta, Stephen M; Wu, Changfu; Duraiswamy, Nandini
2018-06-12
After implantation of a transcatheter bioprosthetic heart valve its original circular circumference may become distorted, which can lead to changes in leaflet coaptation and leaflets that are stretched or sagging. This may lead to early structural deterioration of the valve as seen in some explanted transcatheter heart valves. Our in vitro study evaluates the effect of leaflet deformations seen in elliptical configurations on the damage patterns of the leaflets, with circular valve deformation as the control. Bovine pericardial tissue heart valves were subjected to accelerated wear testing under both circular (N = 2) and elliptical (N = 4) configurations. The elliptical configurations were created by placing the valve inside custom-made elliptical holders, which caused the leaflets to sag or stretch. The hydrodynamic performance of the valves was monitored and high resolution images were acquired to evaluate leaflet damage patterns over time. In the elliptically deformed valves, sagging leaflets experienced more damage from wear compared to stretched leaflets; the undistorted leaflets of the circular valves experienced the least leaflet damage. Free-edge thinning and tearing were the primary modes of damage in the sagging leaflets. Belly region thinning was seen in the undistorted and stretched leaflets. Leaflet and fabric tears at the commissures were seen in all valve configurations. Free-edge tearing and commissure tears were the leading cause of valve hydrodynamic incompetence. Our study shows that mechanical wear affects heart valve pericardial leaflets differently based on whether they are undistorted, stretched, or sagging in a valve configuration. Sagging leaflets are more likely to be subjected to free-edge tear than stretched or undistorted leaflets. Reducing leaflet stress at the free edge of non-circular valve configurations should be an important factor to consider in the design and/or deployment of transcatheter bioprosthetic heart valves to improve their long-term performance.
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The Lγ Phase of Pulmonary Surfactant.
Kumar, Kamlesh; Chavarha, Mariya; Loney, Ryan W; Weiss, Thomas M; Rananavare, Shankar B; Hall, Stephen B
2018-06-05
To determine how different components affect the structure of pulmonary surfactant, we measured X-ray scattering by samples derived from calf surfactant. The surfactant phospholipids demonstrated the essential characteristics of the L γ phase: a unit cell with a lattice constant appropriate for two bilayers, and crystalline chains detected by wide-angle X-ray scattering (WAXS). The electron density profile, obtained from scattering by oriented films at different relative humidities (70-97%), showed that the two bilayers, arranged as mirror images, each contain two distinct leaflets with different thicknesses and profiles. The detailed structures suggest one ordered leaflet that would contain crystalline chains and one disordered monolayer likely to contain the anionic compounds, which constitute ∼10% of the surfactant phospholipids. The spacing and temperature dependence detected by WAXS fit with an ordered leaflet composed of dipalmitoyl phosphatidylcholine. Physiological levels of cholesterol had no effect on this structure. Removing the anionic phospholipids prevented formation of the L γ phase. The cationic surfactant proteins inhibited L γ structures, but at levels unlikely related to charge. Because the L γ phase, if arranged properly, could produce a self-assembled ordered interfacial monolayer, the structure could have important functional consequences. Physiological levels of the proteins, however, inhibit formation of the L γ structures at high relative humidities, making their physiological significance uncertain.
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On the bending properties of porcine mitral, tricuspid, aortic, and pulmonary valve leaflets.
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.
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Huang, H; Zhou, Y; Shao, J; Cai, J; Mei, Y; Wang, Y
2012-12-01
The aim of this paper was to develop a new self-expandable aortic valved stent following the shape of the sinus of Valsalva, which can be deployed above native leaflets for aortic regurgitation, and study it's effect on coronary artery flow when orthotopic implantation in and above native leaflets. New self-expandable aortic valved stent consist of nitinol stent and bovine pericardium, and was designed following the shape of the sinus of Valsalva, the bovine pericardium was tailed as native leaflet. Thirty-six swine hearts were divided into three equal groups of twelve. In Group A (N.=12), the new self-expandable aortic valved stents deployed in native leaflets. In Group B (N.=12), the new self-expandable aortic valved stents deployed above native leaflets. In Group C (N.=12), the cylinder-like valved stents deployed only in native leaflets. The measurements of each coronary flow rate and endoscopic inspections were repeated post-implantation. In Group A and C, valve implantation in native leaflets resulted in a significant decrease in both left and right coronary flows. In Group B, no significant change in either right or left coronary flow was found after new self-expandable aortic valved stent placement. Endoscopic inspections showed that in group A and C the native leaflets sandwiched between valved stent and aortic wall, whereas, in group B the native leaflets were under the artificial leaflets. Two kinds of stents deployed in native leaflets affect left and right coronary flows significantly. No significant effect was found when the new self-expandable aortic valved stent deployed above native leaflets. This new self-expandable aortic valved stent can be deployed above the native leaflets, which avoids the obstruction of native leaflets on coronary flow.
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The readability and suitability of sexual health promotion leaflets.
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.
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He, Shengqiu; Jimenez, Jorge; He, Zhaoming; Yoganathan, Ajit P
2003-05-01
Perturbations of leaflet geometry are the final end point through which left ventricular (LV) ischemia causes incomplete mitral leaflet closure and resultant mitral regurgitation (MR). Geometric inconsistencies observed with valvular or subvalvular structural alterations raise several questions. A new in-vitro LV flexible bag model was developed in order to visualize and analyze leaflet geometric changes under simulated pathological ischemic MR conditions. Papillary muscle (PM) displacement and annular dilatation decreased leaflet coaptation length, leading to significant MR. Symmetrical PM displacement shifted the coaptation line towards the leaflet edges and created central gaps along this line. Asymmetric PM displacement generated diametrically uneven coaptation with a tent-shaped leaflet at the tethered PM side, while the leaflet bulged at the opposite side towards the left atrium. Leaflet geometry during systole is affected by subvalvular structures. Asymmetric PM displacement, which may occur in regional or acute myocardial infarction, induces irregular deformation of the leaflet's coaptation line and, as a result, MR at the tethered side. Direct visualization of leaflet perturbation under these simulated pathological conditions may promote understanding of mechanisms present in ischemic MR.
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Martin, Caitlin
2014-01-01
One of the major failure modes of bioprosthetic heart valves (BHVs) is noncalcific structural deterioration due to fatigue of the tissue leaflets; yet, the mechanisms of fatigue are not well understood. BHV durability is primarily assessed based on visual inspection of the leaflets following accelerated wear testing. In this study, we developed a computational framework to simulate BHV leaflet fatigue, which is both efficient and quantitative, making it an attractive alternative to traditional accelerated wear testing. We utilize a phenomenological soft tissue fatigue damage model developed previously to describe the stress softening and permanent set of the glutaraldehyde-treated bovine pericardium leaflets in BHVs subjected to cyclic loading. A parametric study was conducted to determine the effects of altered leaflet and stent elastic properties on the fatigue of the leaflets. The simulation results show that heterogeneity of the leaflet elastic properties, poor leaflet coaptation, and little stent-tip deflection may accelerate leaflet fatigue, which agrees with clinical findings. Therefore, the developed framework may be an invaluable tool for evaluating leaflet durability in new tissue valve designs, including traditional BHVs as well as new transcatheter valves. PMID:24092257
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Content analysis of nutritional information in paediatric oral health education leaflets.
Arora, Amit; Doan, Jenny; Martinez, Jessamine; Phan, Colin; Kolt, Gregory S; Bhole, Sameer; Harris, Mark Fort; Scott, Jane Anne; Hector, Debra
2017-02-20
The aim of this study was to determine if paediatric oral health education leaflets with a food and nutritional focus provide messages that are clear and consistent with the current Australian Dietary Guidelines and the Infant Feeding Guidelines. Forty-three leaflets aimed at parents were sourced from Australian state and territory Health Departments, oral health industry partners and commercial organisations, and a content analysis was performed. Recommendations on food and drink type, consumption frequency and general diet and nutrition advice were considered and cross-referenced with the Australian Dietary Guidelines and the Infant Feeding Guidelines to identify areas of consistency and discrepancy. Twenty leaflets recommended reducing the consumption of sugary and/or acidic food, while 23 leaflets recommended reducing the consumption of sugary and/or acidic drinks. The majority of the leaflets advised water (n = 35) and milk (n = 23) to drink. Although 33 leaflets encouraged a healthy diet, seven of these did not specify what a healthy diet was. Twenty-eight leaflets provided early childhood-related (0-2 years) feeding advice. Confusing messages were found in nine leaflets, with ambiguous recommendations that were open to individual interpretation. There were some inconsistencies between the leaflets and the dietary and infant feeding guidelines in Australia; and across the leaflets, as not all important messages were included in any one leaflet. Government Health Departments and other relevant agencies should ensure that advisory messages regarding diet, particularly those with dental implications, are clear, complete and consistent across all dental educational leaflets.
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Crutches, confetti or useful tools? Professionals' views on and use of health education leaflets.
Murphy, S; Smith, C
1993-06-01
This paper examines the views on and use of health education leaflets by a number of professional groups: health visitors, midwives, occupational health workers, pharmacists and school health education co-ordinators. Eighty nine percent currently obtain leaflets from health promotion units, with the exception of health visitors, professionals are largely satisfied with the units' service. Seventy six percent use commercial or sponsored leaflets primarily because of the large numbers and topics that are available. The numbers and type of leaflets used were found to vary across the professions. All professionals see an increasingly important role for leaflets in their work. A number of them, pharmacists and occupational health workers in particular, saw the numbers they use rising. These views were accompanied by lower levels of belief in a leaflets ability to increase knowledge and behaviour as well as lower levels of satisfaction with current leaflet use and a concern over the public's reception of leaflets. Methods of leaflet distribution to the public largely reflect the professionals' work contexts. Most popular were handing out leaflets with advice, leaving them in a public place and using them as a back-up to a meeting. A number of contradictions emerge between distribution practices and perceived effectiveness. Few professionals thought leaving leaflets in a public place was effective, and few health visitors and midwives believed giving leaflets to the family of a client was effective despite large numbers doing so. The implications of these findings for health promotion policy and practice are discussed.
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Balshaw, T G; Fry, A; Maden-Wilkinson, T M; Kong, P W; Folland, J P
2017-06-01
The reliability of surface electromyography (sEMG) is typically modest even with rigorous methods, and therefore further improvements in sEMG reliability are desirable. This study compared the between-session reliability (both within participant absolute reliability and between-participant relative reliability) of sEMG amplitude from single vs. average of two distinct recording sites, for individual muscle (IM) and whole quadriceps (WQ) measures during voluntary and evoked contractions. Healthy males (n = 20) performed unilateral isometric knee extension contractions: voluntary maximum and submaximum (60%), as well as evoked twitch contractions on two separate days. sEMG was recorded from two distinct sites on each superficial quadriceps muscle. Averaging two recording sites vs. using single site measures improved reliability for IM and WQ measurements during voluntary (16-26% reduction in within-participant coefficient of variation, CV W ) and evoked contractions (40-56% reduction in CV W ). For sEMG measurements from large muscles, averaging the recording of two distinct sites is recommended as it improves within-participant reliability. This improved sensitivity has application to clinical and research measurement of sEMG amplitude.
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Advertising, expectations and informed consent: the contents and functions of acupuncture leaflets.
Bishop, Felicity L; Salmon, Cathy
2013-12-01
To evaluate the content of patient information leaflets about acupuncture. 401 patient information leaflets were obtained from practising UK acupuncturists and subjected to content and thematic analysis. 59% of included leaflets were from NHS physiotherapists. Almost all the leaflets defined acupuncture and the majority explained how it might work, described the treatment process and placed it in a historical context. Most described possible benefits and risks of acupuncture and discussed contraindications and safety. Just under a third of leaflets (120, 30%) suggested conditions that might be helped by acupuncture, most commonly musculoskeletal pain, arthritis and injuries. By emphasising differences between individuals in acupuncture treatments and responsiveness, the leaflets fostered hope for positive effects without making any guarantees. Information leaflets are broadly consistent with the evidence for acupuncture, but some claims are inconsistent with official advice from advertising regulators. An ethically sound, scientifically grounded and psychologically effective leaflet should accurately convey both benefits and risks of treatment, optimise patients' expectations and allay concerns about needling. This study suggests that acupuncture leaflets might achieve these multiple functions but care should be taken to ensure adequate coverage of risks.
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Chung, ChiHye; Barlyko, Barbara; Leitz, Jeremy; Liu, Xinran; Kavalali, Ege T.
2010-01-01
Synapses maintain synchronous, asynchronous and spontaneous forms of neurotransmission that are distinguished by their Ca2+-dependence and time course. Despite recent advances in our understanding of the mechanisms that underlie these three forms of release, it remains unclear whether they originate from the same vesicle population or arise from distinct vesicle pools with diverse propensities for release. Here, we used a reversible inhibitor of dynamin, dynasore, to dissect the vesicle pool dynamics underlying the three forms of neurotransmitter release in hippocampal GABAergic inhibitory synapses. In dynasore, evoked synchronous release and asynchronous neurotransmission detected after activity showed marked and unrecoverable depression within seconds. In contrast, spontaneous release remained intact after intense stimulation in dynasore or during prolonged (~1 hour) application of dynasore at rest, suggesting that separate recycling pathways maintain evoked and spontaneous synaptic vesicle trafficking. In addition, simultaneous imaging of spectrally separable styryl dyes revealed that in a given synapse vesicles that recycle spontaneously and in response to activity do not mix. These findings suggest that evoked synchronous and asynchronous release originate from the same vesicle pool that recycles rapidly in a dynamin-dependent manner, while a distinct vesicle pool sustains spontaneous release independent of dynamin activation. This result lends further support to the notion that synapses harbor distinct vesicle populations with divergent release properties that maintain independent forms of neurotransmission. PMID:20107062
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Xuan, Yue; Krishnan, Kapil; Ye, Jian; Dvir, Danny; Guccione, Julius M; Ge, Liang; Tseng, Elaine E
2017-05-01
Transcatheter aortic valve replacement is established therapy for high-risk and inoperable patients with severe aortic stenosis, but questions remain regarding long-term durability. Valve design influences durability. Increased leaflet stresses in surgical bioprostheses have been correlated with degeneration; however, transcatheter valve leaflet stresses are unknown. From 2007 to 2014, a majority of US patients received first-generation balloon-expandable transcatheter valves. Our goal was to determine stent and leaflet stresses in this valve design using finite element analyses. A 26-mm Sapien Transcatheter Heart Valve (Edwards Lifesciences, Inc, Irvine, Calif) underwent high-resolution microcomputed tomography scanning to develop precise 3-dimensional geometry of the leaflets, the stent, and the polyethylene terephthalate elements. The stent was modeled using 3-dimensional elements and the leaflets were modeled using shell elements. Stent material properties were based on stainless steel, whereas those for leaflets were obtained from surgical bioprostheses. Noncylindrical Sapien valve geometry was also simulated. Pressure loading to 80 mm Hg and 120 mm Hg was performed using ABAQUS finite element software (Dassault Systèmes, Waltham, Mass). At 80 mm Hg, maximum principal stresses on Sapien leaflets were 1.31 megaspascals (MPa). Peak leaflet stress was observed at commissural tips where leaflets connected to the stent. Maximum principal stresses for the stent were 188.91 MPa and located at stent tips where leaflet commissures were attached. Noncylindrical geometry increased peak principal leaflet stresses by 16%. Using exact geometry from high-resolution scans, the 26-mm Sapien Transcatheter Heart Valve showed that peak stresses for both stent and leaflets were present at commissural tips where leaflets were attached. These regions would be prone to leaflet degeneration. Understanding stresses in first-generation transcatheter valves allows comparison to future designs for relative durability. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
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NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.
Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M
2015-01-21
A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 Gαq and egl-8 PLCβ) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 Gαq and egl-8 PLCβ and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. Copyright © 2015 the authors 0270-6474/15/351038-05$15.00/0.
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'What do patients want?' Tailoring medicines information to meet patients' needs.
Young, Amber; Tordoff, June; Smith, Alesha
2017-11-01
Medicines information leaflets can equip patients to be in control of their own healthcare and support the safe and effective use of medicines. The design and content of leaflets influences patients' willingness to read them, and poor examples can cause patient confusion and anxiety. Researchers examined the literature over the past 8 years to determine the content and design of medicine information leaflets that patients prefer in order to read, understand, and use them effectively. It was found that existing leaflets do not meet patients' needs and appear ineffective. Leaflets lack the information patients seek and may contain non-essential material, affecting patients' perception of, and willingness to read them. Additionally, the acceptable leaflet length varies between patients. Application of good design principles improves readability, comprehension, and ability to locate information. Medicine information leaflets must meet patients' needs and be well designed. Tailoring information leaflets to patient characteristics and requirements would enhance effectiveness. Passive provision of pre-printed leaflets is outdated, unvalued and ineffective. Using automated computer systems for leaflet tailoring with the ability to further adapt patients' information might be the best way forward. Copyright © 2016 Elsevier Inc. All rights reserved.
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Venkatraman, Vinod; Rosati, Alexandra G; Taren, Adrienne A; Huettel, Scott A
2009-10-21
The dorsomedial prefrontal cortex (DMPFC) plays a central role in aspects of cognitive control and decision making. Here, we provide evidence for an anterior-to-posterior topography within the DMPFC using tasks that evoke three distinct forms of control demands--response, decision, and strategic--each of which could be mapped onto independent behavioral data. Specifically, we identify three spatially distinct regions within the DMPFC: a posterior region associated with control demands evoked by multiple incompatible responses, a middle region associated with control demands evoked by the relative desirability of decision options, and an anterior region that predicts control demands related to deviations from an individual's preferred decision-making strategy. These results provide new insight into the functional organization of DMPFC and suggest how recent controversies about its role in complex decision making and response mapping can be reconciled.
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Distinct cortical circuit mechanisms for complex forelimb movement and motor map topography.
Harrison, Thomas C; Ayling, Oliver G S; Murphy, Timothy H
2012-04-26
Cortical motor maps are the basis of voluntary movement, but they have proven difficult to understand in the context of their underlying neuronal circuits. We applied light-based motor mapping of Channelrhodopsin-2 mice to reveal a functional subdivision of the forelimb motor cortex based on the direction of movement evoked by brief (10 ms) pulses. Prolonged trains of electrical or optogenetic stimulation (100-500 ms) targeted to anterior or posterior subregions of motor cortex evoked reproducible complex movements of the forelimb to distinct positions in space. Blocking excitatory cortical synaptic transmission did not abolish basic motor map topography, but the site-specific expression of complex movements was lost. Our data suggest that the topography of movement maps arises from their segregated output projections, whereas complex movements evoked by prolonged stimulation require intracortical synaptic transmission. Copyright © 2012 Elsevier Inc. All rights reserved.
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Venkatraman, Vinod; Rosati, Alexandra G.; Taren, Adrienne A.; Huettel, Scott A.
2009-01-01
The dorsomedial prefrontal cortex (DMPFC) plays a central role in aspects of cognitive control and decision making. Here, we provide evidence for an anterior-to-posterior topography within the DMPFC using tasks that evoke three distinct forms of control demands – response, decision, and strategic – each of which could be mapped on to independent behavioral data. Specifically, we identify three spatially distinct regions within the DMPFC: a posterior region associated with control demands evoked by multiple incompatible responses, a middle region associated with control demands evoked by the relative desirability of decision options, and an anterior region that predicts control demands related to deviations from an individual's preferred decision-making strategy. These results provide new insight into the functional organization of DMPFC, and suggest how recent controversies about its role in complex decision making and response mapping can be reconciled. PMID:19846703
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Sweet, W D; Schroeder, F
1986-01-01
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. PMID:3028369
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Arora, Amit; Al-Salti, Ibrahim; Murad, Hussam; Tran, Quang; Itaoui, Rhonda; Bhole, Sameer; Ajwani, Shilpi; Jones, Charlotte; Manohar, Narendar
2018-01-10
The purpose of this study was to gain an in-depth understanding of Arabic-speaking mothers views on the usefulness of existing oral health education leaflets aimed at young children and also to record their views on the tailored versions of these leaflets. This qualitative study was nested within a large ongoing birth cohort study in South Western Sydney, Australia. Arabic-speaking mothers (n = 19) with young children were purposively selected and approached for a semi-structured interview. Two original English leaflets giving advice on young children's oral health were sent to mother's prior to the interview. On the day of interview, mothers were given simplified-English and Arabic versions of both the leaflets and were asked to compare the three versions. Interviews were audio-recorded, subsequently transcribed verbatim and analysed by thematic analysis. Ethical approval was obtained from Human Research Ethics Committees of the former Sydney South West Area Health Service, University of Sydney and Western Sydney University. Mothers reported that simplified English together with the Arabic version of the leaflets were useful sources of information. Although many mothers favoured the simplified version over original English leaflets, the majority favoured the leaflets in Arabic. Ideally, a "dual Arabic - simplified English leaflet" was preferred. The understanding of key health messages was optimised through a simple layout and visual images. There is a need to tailor oral health education leaflets for Arabic-speaking migrants. Producers of dental leaflets should also consider a "dual Arabic - simplified English leaflet" to improve oral health knowledge of Arabic-speaking migrants. The use of simple layout and pictures assists Arabic-speaking migrants to understand the content of dental leaflets.
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Li, Kewei; Sun, Wei
2017-03-01
In this study, we developed a computational framework to investigate the impact of leaflet geometry of a transcatheter aortic valve (TAV) on the leaflet stress distribution, aiming at optimizing TAV leaflet design to reduce its peak stress. Utilizing a generic TAV model developed previously [Li and Sun, Annals of Biomedical Engineering, 2010. 38(8): 2690-2701], we first parameterized the 2D leaflet geometry by mathematical equations, then by perturbing the parameters of the equations, we could automatically generate a new leaflet design, remesh the 2D leaflet model and build a 3D leaflet model from the 2D design via a Python script. Approximately 500 different leaflet designs were investigated by simulating TAV closure under the nominal circular deployment and physiological loading conditions. From the simulation results, we identified a new leaflet design that could reduce the previously reported valve peak stress by about 5%. The parametric analysis also revealed that increasing the free edge width had the highest overall impact on decreasing the peak stress. A similar computational analysis was further performed for a TAV deployed in an abnormal, asymmetric elliptical configuration. We found that a minimal free edge height of 0.46 mm should be adopted to prevent central backflow leakage. This increase of the free edge height resulted in an increase of the leaflet peak stress. Furthermore, the parametric study revealed a complex response surface for the impact of the leaflet geometric parameters on the peak stress, underscoring the importance of performing a numerical optimization to obtain the optimal TAV leaflet design. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
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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.
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Effects of Leaflet Design on Transvalvular Gradients of Bioprosthetic Heart Valves.
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.
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Congenital uni-leaflet mitral valve with severe stenosis: A case report with literature review.
Zhang, Weixin; Wang, Yonghuai; Ma, Chunyan; Zhang, Zhiwei; Yang, Jun
2017-03-01
Numerical abnormalities of mitral leaflets is a special entity in congenital mitral malformations. Previously reported cases of uni-leaflet mitral valve were primarily related to absence or dysplasia of certain leaflets. We present a case here with mitral leaflets that were not divided into anterior and posterior as usual, but developed as an integral structure instead, which is different from previously documented cases of uni-leaflet mitral valves. Real time three-dimensional echocardiography (RT3DE) provides a visual presentation of the abnormal mitral structure which was confirmed by surgical operation. To the best of our knowledge, this unusual form of uni-leaflet mitral valve has not been reported yet. © 2017, Wiley Periodicals, Inc.
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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
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Mittermeier, Verena; Leicht, Gregor; Karch, Susanne; Hegerl, Ulrich; Möller, Hans-Jürgen; Pogarell, Oliver; Mulert, Christoph
2011-03-01
Several studies suggest that attention to emotional content is related to specific changes in central information processing. In particular, event-related potential (ERP) studies focusing on emotion recognition in pictures and faces or word processing have pointed toward a distinct component of the visual-evoked potential, the EPN ('early posterior negativity'), which has been shown to be related to attention to emotional content. In the present study, we were interested in the existence of a corresponding ERP component in the auditory modality and a possible relationship with the personality dimension extraversion-introversion, as assessed by the NEO Five-Factors Inventory. We investigated 29 healthy subjects using three types of auditory choice tasks: (1) the distinction of syllables with emotional intonation, (2) the identification of the emotional content of adjectives and (3) a purely cognitive control task. Compared with the cognitive control task, emotional paradigms using auditory stimuli evoked an EPN component with a distinct peak after 170 ms (EPN 170). Interestingly, subjects with high scores in the personality trait extraversion showed significantly higher EPN amplitudes for emotional paradigms (syllables and words) than introverted subjects.
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Behavior of Bilayer Leaflets in Asymmetric Model Membranes: Atomistic Simulation Studies
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-plane lipid packing, possibly providing a mechanism for interleaflet coupling by modulating local density and/or curvature fluctuations.« less
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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.
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Abbasi, Mostafa; Azadani, Ali N
2017-07-01
In order to accommodate transcatheter valves to miniaturized catheters, the leaflet thickness must be reduced to a value which is typically less than that of surgical bioprostheses. The study aim was to use finite-element simulations to determine the impact of the thickness reduction on stress and strain distribution. A 23 mm transcatheter aortic valve (TAV) was modelled based on the Edwards SAPIEN XT (Edwards Lifesciences, Irvine, CA, USA). Finite-element (FE) analysis was performed using the ABAQUS/Explicit solver. An ensemble-averaged transvalvular pressure waveform measured from in-vitro tests conducted in a pulse duplicator was applied to the leaflets. Through a parametric study, uniform TAV leaflet thickness was reduced from 0.5 to 0.18 mm. By reducing leaflet thickness, significantly higher stress values were found in the leaflet's fixed edge during systole, and in the commissures during diastole. Through dynamic FE simulations, the highest stress values were found during systole in the leaflet fixed edge. In contrast, at the peak of diastole high-stress regions were mainly observed in the commissures. The peak stress was increased by 178% and 507% within the leaflets after reducing the thickness of 0.5 mm to 0.18 mm at the peak of systole and diastole, respectively. The study results indicated that, the smaller the leaflet thickness, the higher the maximum principal stress. Increased mechanical stress on TAV leaflets may lead to accelerated tissue degeneration. By using a thinner leaflet, TAV durability may not atch with that of surgical bioprostheses.
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Category cued recall evokes a generate-recognize retrieval process.
Hunt, R Reed; Smith, Rebekah E; Toth, Jeffrey P
2016-03-01
The experiments reported here were designed to replicate and extend McCabe, Roediger, and Karpicke's (2011) finding that retrieval in category cued recall involves both controlled and automatic processes. The extension entailed identifying whether distinctive encoding affected 1 or both of these 2 processes. The first experiment successfully replicated McCabe et al., but the second, which added a critical baseline condition, produced data inconsistent with a 2 independent process model of recall. The third experiment provided evidence that retrieval in category cued recall reflects a generate-recognize strategy, with the effect of distinctive processing being localized to recognition. Overall, the data suggest that category cued recall evokes a generate-recognize retrieval strategy and that the subprocesses underlying this strategy can be dissociated as a function of distinctive versus relational encoding processes. (c) 2016 APA, all rights reserved).
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Category Cued Recall Evokes a Generate-Recognize Retrieval Process
Hunt, R. Reed; Smith, Rebekah E.; Toth, Jeffrey P.
2015-01-01
The experiments reported here were designed to replicate and extend McCabe, Roediger, and Karpicke’s (2011) finding that retrieval in category cued recall involves both controlled and automatic processes. The extension entailed identifying whether distinctive encoding affected one or both of these two processes. The first experiment successfully replicated McCabe et al., but the second, which added a critical baseline condition, produced data inconsistent with a two independent process model of recall. The third experiment provided evidence that retrieval in category cued recall reflects a generate-recognize strategy, with the effect of distinctive processing being localized to recognition. Overall, the data suggest that category cued recall evokes a generate-recognize retrieval strategy and that the sub-processes underlying this strategy can be dissociated as a function of distinctive versus relational encoding processes. PMID:26280355
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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…
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Development of visual evoked potentials in neonates. A study using light emitting diode goggles.
Chin, K C; Taylor, M J; Menzies, R; Whyte, H
1985-01-01
We used a signal averager with light emitting diode goggles as the photostimulator to study the development of the visual evoked potentials in 40 normal neonates of between 23 and 42 weeks' gestation. All except two infants of less than 24 weeks' gestation had replicable visual evoked potentials. A negative peak of latency (mean (SD), 308 (21) msec) was present in all infants, but the development of the primary positive peak depended on maturity. Only infants of 37 weeks or more had a consistent positive peak of latency (mean (SD), 220 (22) msec). The practical simplicity and reliability of this technique has distinct advantages over previous conventional recording systems. Neonatal visual evoked potentials are shown to change with maturity. PMID:4091582
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Promotion of family planning services in practice leaflets.
Marshall, M N; Gray, D J; Pearson, V; Phillips, D R; Owen, M
1994-10-08
Providing 75% of family planning services in the United Kingdom, general practitioners are required to produce leaflets which describe the contraceptive services they provide. The authors analyzed information about family planning provided to clients through practice leaflets. 88% of practice leaflets from the 198 practices in Devon were available from the Devon Family Health Services Authority for analysis. It was determined that the leaflets are not being best used to advertise the range and potential of family planning services. Although all practices in Devon offer contraceptive services, only 90% of leaflets mentioned that the services are available. Reference to postcoital contraception and information about services outside the practice for people who might not want to see their family doctor are also sorely lacking. A clear need exists to provide patients with more information. Finally, the authors found that group practices and those with female partners are most likely to give high priority to family planning issues in their leaflets.
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[Evaluation of a self-care leaflet].
Lystad, N; Heian, F
1989-01-20
A self care leaflet of 50 pages was distributed in Tingvoll, a municipality with 3,500 inhabitants. The leaflet gives advice about self treatment and prevention of common health problems, and guidelines for contacting the health services. In surveys conducted just before and 10 months after the distribution, we documented -- how the leaflet was accepted and used --changes in knowledge about the health problems mentioned in the leaflet. The leaflet was well accepted. It was characterized as easy to read and to use. 10 months after distribution to read and to use. 10 months after distribution 90% found it within five minutes. 63% used the leaflet when they had a health problem. 90% of those using the leaflet felt more sure that they acted correctly after consulting it, and 60% changed their mind about consulting a general practitioner. We consider the level of knowledge about health problems to be low. The evaluation showed increased knowledge in all groups, except for persons "responsible for caring for elderly relatives". The increase was most marked for "men" and for "persons with health education".
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Eicher, Barbara; Marquardt, Drew; Heberle, Frederick A.
We measured the effect of intrinsic lipid curvature, J 0, on structural properties of asymmetric vesicles made of palmitoyl-oleoyl-phosphatidylethanolamine (POPE; J 0 < 0) and palmitoyl-oleoyl-phosphatidylcholine (POPC; J 0 ~ 0). Electron microscopy and dynamic light scattering were used to determine vesicle size and morphology, and x-ray and neutron scattering, combined with calorimetric experiments and solution NMR, yielded insights into leaflet-specific lipid packing and melting processes. Below the lipid melting temperature we observed strong interleaflet coupling in asymmetric vesicles with POPE inner bilayer leaflets and outer leaflets enriched in POPC. This lipid arrangement manifested itself by lipids melting cooperatively inmore » both leaflets, and a rearrangement of lipid packing in both monolayers. On the other hand, no coupling was observed in vesicles with POPC inner bilayer leaflets and outer leaflets enriched in POPE. In this case, the leaflets melted independently and did not affect each other’s acyl chain packing. Furthermore, we found no evidence for transbilayer structural coupling above the melting temperature of either sample preparation. Our results are consistent with the energetically preferred location of POPE residing in the inner leaflet, where it also resides in natural membranes, most likely causing the coupling of both leaflets. The loss of this coupling in the fluid bilayers is most likely the result of entropic contributions.« less
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Chan, Vincent; Chu, Michael W A; Leong-Poi, Howard; Latter, David A; Hall, Judith; Thorpe, Kevin E; de Varennes, Benoit E; Quan, Adrian; Tsang, Wendy; Dhingra, Natasha; Yared, Kibar; Teoh, Hwee; Chu, F Victor; Chan, Kwan-Leung; Mesana, Thierry G; Connelly, Kim A; Ruel, Marc; Jüni, Peter; Mazer, C David; Verma, Subodh
2017-05-30
The gold-standard treatment of severe mitral regurgitation (MR) due to degenerative disease is valve repair, which is surgically performed with either a leaflet resection or leaflet preservation approach. Recent data suggest that functional mitral stenosis (MS) may occur following valve repair using a leaflet resection strategy, which adversely affects patient prognosis. A randomised comparison of these two approaches to mitral repair on functional MS has not been conducted. This is a prospective, multicentre randomised controlled trial designed to test the hypothesis that leaflet preservation leads to better preservation of mitral valve geometry, and therefore, will be superior to leaflet resection for the primary outcome of functional MS as assessed by 12-month mean mitral valve gradient at peak exercise. Eighty-eight patients with posterior leaflet prolapse will be randomised intraoperatively once deemed by the operating surgeon to feasibly undergo mitral repair using either a leaflet resection or leaflet preservation approach. Secondary end points include comparison of repair strategies with regard to mitral valve orifice area, leaflet coaptation height, 6 min walk test and a composite major adverse event end point consisting of recurrent MR ≥2+, death or hospital readmission for congestive heart failure within 12 months of surgery. Institutional ethics approval has been obtained from all enrolling sites. Overall, there remains clinical equipoise regarding the mitral valve repair strategy that is associated with the least likelihood of functional MS. This trial hopes to introduce high-quality evidence to help surgical decision making in this context. NCT02552771. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
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Byrom, J; Dunn, P D J; Hughes, G M; Lockett, J; Johnson, A; Neale, J; Redman, C W E
2003-01-01
To evaluate whether the information leaflets produced by UK colposcopy clinics provide women with the information they desire and to determine when they would like to receive this information. Questionnaire study and structured evaluation. The colposcopy clinic of a UK cancer centre. Forty-two women attending a pre-colposcopy counselling session and 100 consecutive women attending the colposcopy clinic. Thirty-eight standards derived from the concerns/questions asked by women attending a pre-colposcopy counselling session were used to assess locally produced colposcopy clinic leaflets from UK colposcopy clinics, the leaflets produced by the Royal College of Obstetricians and Gynaecologists and the National Health Service Cervical Screening Programme (NHSCSP), and two "leaflets" obtained from internet sites. The Gunning fog test was used to assess the leaflets' readability. A questionnaire survey of 100 women attending the colposcopy clinic was used to determine when women wanted to receive information about colposcopy. Percentage of questions answered by a given leaflet and Gunning fog scores for readability. The information leaflets of 128 colposcopy clinics were received and assessed. Thirty-two clinics only sent women the NHSCSP leaflet. No leaflet answered all 38 questions. Less than half (36/100) of the leaflets answered more than 50% of the questions. In addition to the lack of advice given, different leaflets frequently gave conflicting advice. The average Gunning fog score was 9.7 (range 5.5-15.5). The majority of women (70%) wanted to receive information about colposcopy at or prior to the time of receiving their abnormal smear test result, although only 42% of women actually received information at this time. Many UK colposcopy clinics do not appear to be providing women with the information they require to understand their condition and the procedure that they are about to undergo. Furthermore, this information is often not provided at the appropriate time in the screening process.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tian, Jianhui; Nickels, Jonathan; Katsaras, John
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-plane lipid packing, possibly providing a mechanism for interleaflet coupling by modulating local density and/or curvature fluctuations.« less
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Wegwarth, O; Kurzenhäuser-Carstens, S; Gigerenzer, G
2014-03-10
Informed decision making requires transparent and evidence-based (=balanced) information on the potential benefit and harms of medical preventions. An analysis of German HPV vaccination leaflets revealed, however, that none met the standards of balanced risk communication. We surveyed a sample of 225 girl-parent pairs in a before-after design on the effects of balanced and unbalanced risk communication on participants' knowledge about cervical cancer and the HPV vaccination, their perceived risk, their intention to have the vaccine, and their actual vaccination decision. The balanced leaflet increased the number of participants who were correctly informed about cervical cancer and the HPV vaccine by 33 to 66 absolute percentage points. In contrast, the unbalanced leaflet decreased the number of participants who were correctly informed about these facts by 0 to 18 absolute percentage points. Whereas the actual uptake of the HPV vaccination 14 months after the initial study did not differ between the two groups (22% balanced leaflet vs. 23% unbalanced leaflet; p=.93, r=.01), the originally stated intention to have the vaccine reliably predicted the actual vaccination decision for the balanced leaflet group only (concordance between intention and actual uptake: 97% in the balanced leaflet group, rs=.92, p=.00; 60% in the unbalanced leaflet group, rs=.37, p=.08). In contrast to a unbalanced leaflet, a balanced leaflet increased people's knowledge of the HPV vaccination, improved perceived risk judgments, and led to an actual vaccination uptake, which first was robustly predicted by people's intention and second did not differ from the uptake in the unbalanced leaflet group. These findings suggest that balanced reporting about HPV vaccination increases informed decisions about whether to be vaccinated and does not undermine actual uptake. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.
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[Parenting Renewal. Leaflets and Lessons for Parents of Children Birth to Four.
ERIC Educational Resources Information Center
Clemson Univ., SC. Cooperative Extension Service.
Instructional materials on parenting skills for parents of newborn through 4-year-old children are provided, with teaching guides for extension service agents. Organized as a series of nine leaflets followed by nine corresponding lessons, leaflets for parents concern: (1) an overview of the leaflets; (2) readiness: guiding normal development; (3)…
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Flow-induced Flutter of Heart Valves: Experiments with Canonical Models
NASA Astrophysics Data System (ADS)
Dou, Zhongwang; Seo, Jung-Hee; Mittal, Rajat
2017-11-01
For the better understanding of hemodynamics associated with valvular function in health and disease, the flow-induced flutter of heart valve leaflets is studied using benchtop experiments with canonical valve models. A simple experimental model with flexible leaflets is constructed and a pulsatile pump drives the flow through the leaflets. We quantify the leaflet dynamics using digital image analysis and also characterize the dynamics of the flow around the leaflets using particle imaging velocimetry. Experiments are conducted over a wide range of flow and leaflet parameters and data curated for use as a benchmark for validation of computational fluid-structure interaction models. The authors would like to acknowledge Supported from NSF Grants IIS-1344772, CBET-1511200 and NSF XSEDE Grant TG-CTS100002.
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Fedele, T; Scheer, H-J; Burghoff, M; Waterstraat, G; Nikulin, V V; Curio, G
2013-01-01
Non-invasively recorded averaged event-related potentials (ERP) represent a convenient opportunity to investigate human brain perceptive and cognitive processes. Nevertheless, generative ERP mechanisms are still debated. Two previous approaches have been contested in the past: the added-energy model in which the response raises independently from the ongoing background activity, and the phase-reset model, based on stimulus-driven synchronization of oscillatory ongoing activity. Many criteria for the distinction of these two models have been proposed, but there is no definitive methodology to disentangle them, owing also to the limited information at the single trial level. Here, we propose a new approach combining low-noise EEG technology and multivariate decomposition techniques. We present theoretical analyses based on simulated data and identify in high-frequency somatosensory evoked responses an optimal target for the distinction between the two mechanisms.
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The contents of dental implant patient information leaflets available within the UK.
Barber, J; Puryer, J; McNally, L; O'Sullivan, D
2015-02-01
Patient information leaflets are designed to provide easy to follow information summaries and first point of contact information about treatment options. This survey reviewed the content of dental implant patient information leaflets, produced by implant companies and available within the UK in 2011. Dental implant companies in the UK were asked to provide samples of their patient information leaflets. The information within the leaflets was then summarised, including the quantity and the types of images used and whether the source of the information was given. Quantitative data was obtained on the amount of information provided, size of images and number of references. A response rate of 71% was obtained and 23 leaflets were studied. Great variation was found between the leaflets, with the word counts ranging from 88 to 5,434, and 44 different topics were identified. The majority of the images used were decorative, and none of the leaflets gave any reference to the sources of their information. Implant treatment was generally described in a positive way, with an emphasis on describing the treatment and the advantages. Much less information was given about the potential disadvantages and risks of complications or failure, including the relevance of periodontal disease or smoking. Implant patient information leaflets provided by dental implant companies should not be solely relied upon to provide patients with all the information they need to give informed consent to treatment.
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Smith, Samuel G; Wolf, Michael S; Obichere, Austin; Raine, Rosalind; Wardle, Jane; von Wagner, Christian
2013-12-01
To design and user-test a 'gist-based' colorectal cancer screening information leaflet, which promotes comprehension of the screening offer. Twenty-eight individuals approaching screening age were recruited from organisations in deprived areas of England. Using a between-subjects design, we tested iterations of a newly-designed gist-based information leaflet. Participants read the leaflet and answered 8 'true' or 'false' comprehension statements. For the leaflet to be considered fit-for-purpose, all statements had to be answered correctly by at least 80% of participants in each round. Alterations were made if this threshold was not met and additional rounds of testing were undertaken. At round 1, answers to 2/8 statements did not meet the threshold. After changes, answers in round 2 did not reach the threshold for 1/8 statements. In round 3, all answers were adequate and the leaflet was deemed fit-for-purpose. Qualitative data offered solutions such as language and layout changes which led to improved comprehension of the leaflet. User-testing substantially improved the design and subsequent comprehensibility of a theory-driven gist-based colorectal cancer screening information leaflet. This leaflet will be evaluated as part of a large national randomised controlled trial designed to reduce socioeconomic inequalities in colorectal cancer screening participation. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.
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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.
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Jezyk, Damian; Jerzemowski, Janusz; Grzybiak, Marek
2003-01-01
Leaflets of the tricuspid valve are provided by tendinous cords extending from the papillary muscles. The situation is complicated with the septal muscles, which generally occur in two groups, one as constant musculus coni arteriosi and the second as other variable septal muscles. We tested whether there is a variability in the provision of the tricuspid valve in different taxonomical groups of mammals. The material examined consisted of 299 hearts of mammals (Primates, Ungulata, Carnivora, Lagomorpha, Rodentia, Marsupialia). The musculus coni arteriosi in the majority of mammals provided only the front leaflet, but among Ungulata and Rodentia it provided simultaneously the front and septal leaflet. The other septal muscles provided the front, septal and even back leaflets. The following regularity was observed: in the hearts of Primates provision of the front leaflet and the front part of the septal leaflet predominated, among Ungulata the muscles provided the middle part of the septal leaflet, but among the other mammals the rest of the septal muscles provided, significantly, the back part of the septal leaflet. Such a provision was characteristic for predators, hares, rodents and marsupials. These circumstances may allow the conclusion to be drawn that there is a taxonomical dependence in the provision of the tricuspid valve in the hearts of the mammals under examination.
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Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles
Eicher, Barbara; Marquardt, Drew; Heberle, Frederick A.; ...
2018-01-09
We measured the effect of intrinsic lipid curvature, J 0, on structural properties of asymmetric vesicles made of palmitoyl-oleoyl-phosphatidylethanolamine (POPE; J 0 < 0) and palmitoyl-oleoyl-phosphatidylcholine (POPC; J 0 ~ 0). Electron microscopy and dynamic light scattering were used to determine vesicle size and morphology, and x-ray and neutron scattering, combined with calorimetric experiments and solution NMR, yielded insights into leaflet-specific lipid packing and melting processes. Below the lipid melting temperature we observed strong interleaflet coupling in asymmetric vesicles with POPE inner bilayer leaflets and outer leaflets enriched in POPC. This lipid arrangement manifested itself by lipids melting cooperatively inmore » both leaflets, and a rearrangement of lipid packing in both monolayers. On the other hand, no coupling was observed in vesicles with POPC inner bilayer leaflets and outer leaflets enriched in POPE. In this case, the leaflets melted independently and did not affect each other’s acyl chain packing. Furthermore, we found no evidence for transbilayer structural coupling above the melting temperature of either sample preparation. Our results are consistent with the energetically preferred location of POPE residing in the inner leaflet, where it also resides in natural membranes, most likely causing the coupling of both leaflets. The loss of this coupling in the fluid bilayers is most likely the result of entropic contributions.« less
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Hirsh, Di; Clerehan, Rosemary; Staples, Margaret; Osborne, Richard H; Buchbinder, Rachelle
2009-11-01
To obtain patient feedback about the structure and quality of medication information leaflets and validate the usefulness of the Evaluative Linguistic Framework (ELF) for improving written communication with patients. Triangulated feedback about a set of rheumatoid arthritis (RA) medication leaflets, some developed with knowledge of the ELF, was obtained from 27 people with RA from interviews, focus group discussion and self-administered questionnaires. The principal elements of the framework were investigated: overall generic structure and functions of each stage, interpersonal relationship between writer and reader, technicality of language and density of information. Participant assessments of the leaflets aligned with the framework in terms of what constituted a good leaflet. While the main purpose of the leaflets was identified as being information provision, participants also wanted clear instructions, benefits to be highlighted and side effects to be comprehensively listed. For comprehensiveness and user-friendliness, leaflets developed with guidance of the ELF were consistently preferred. According to people with RA, leaflets generated from a linguistic framework are clearer and more effective in communicating information about medications. The ELF is a user-friendly, structured analytic system that can assist with the development of effective high quality patient information materials.
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Optimal Elastomeric Scaffold Leaflet Shape for Pulmonary Heart Valve Leaflet Replacement
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
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Meningioma of the superior leaflet of the velum interpositum: A case report
Champagne, Pierre-Olivier; Bojanowski, Michel W.
2015-01-01
Background: Meningiomas of the velum interpositum in the roof of the third ventricle are rare. Knowing from which leaflet the meningioma originates and thus its relationships with the internal cerebral and Galen veins, may help in choosing the surgical approach. Case Description: We report the case of a 40-year-old male with a meningioma arising from the superior leaflet of the velum interpositum. The tumor was resected successfully using the infratentorial-supracerebellar approach. Reviewing the literature, of the 22 reported cases of velum interpositum meningiomas, sufficient information regarding the precise location of the origin of the tumor was provided in 14 cases, all of which were from the inferior leaflet. Conclusion: We report the first case of velum interpositum meningioma arising from the superior leaflet and give a potential explanation as to why meningiomas of the velum interpositum occur more commonly on the inferior leaflet. Distinguishing from which of the two leaflets the tumor originates may influence the surgical strategy. PMID:25949856
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Curved butterfly bileaflet prosthetic cardiac valve
McQueen, David M.; Peskin, Charles S.
1991-06-25
An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.
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Properties of visual evoked potentials to onset of movement on a television screen.
Kubová, Z; Kuba, M; Hubacek, J; Vít, F
1990-08-01
In 80 subjects the dependence of movement-onset visual evoked potentials on some measures of stimulation was examined, and these responses were compared with pattern-reversal visual evoked potentials to verify the effectiveness of pattern movement application for visual evoked potential acquisition. Horizontally moving vertical gratings were generated on a television screen. The typical movement-onset reactions were characterized by one marked negative peak only, with a peak time between 140 and 200 ms. In all subjects the sufficient stimulus duration for acquisition of movement-onset-related visual evoked potentials was 100 ms; in some cases it was only 20 ms. Higher velocity (5.6 degree/s) produced higher amplitudes of movement-onset visual evoked potentials than did the lower velocity (2.8 degrees/s). In 80% of subjects, the more distinct reactions were found in the leads from lateral occipital areas (in 60% from the right hemisphere), with no correlation to handedness of subjects. Unlike pattern-reversal visual evoked potentials, the movement-onset responses tended to be larger to extramacular stimulation (annular target of 5 degrees-9 degrees) than to macular stimulation (circular target of 5 degrees diameter).
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Johnson, Brett A.; Ong, Joan; Leon, Michael
2014-01-01
To determine how responses evoked by natural odorant mixtures compare to responses evoked by individual odorant chemicals, we mapped 2-deoxyglucose uptake during exposures to vapors arising from a variety of odor objects that may be important to rodents in the wild. We studied 21 distinct natural odor stimuli ranging from possible food sources such as fruits, vegetables, and meats to environmental odor objects such as grass, herbs, and tree leaves. The natural odor objects evoked robust and surprisingly focal patterns of 2-deoxyglucose uptake involving clusters of neighboring glomeruli, thereby resembling patterns evoked by pure chemicals. Overall, the patterns were significantly related to patterns evoked by monomolecular odorant components that had been studied previously. Object patterns also were significantly related to the molecular features present in the mixture components. Despite these overall relationships, there were individual examples of object patterns that were simpler than might have been predicted given the multiplicity of components present in the vapors. In these cases, the object patterns lacked certain responses evoked by their major odorant mixture components. These data suggest the possibility of mixture response interactions and provide a foundation for understanding the neural coding of natural odor stimuli. PMID:20187145
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Anaesthesia information--what patients want to know.
Garden, A L; Merry, A F; Holland, R L; Petrie, K J
1996-10-01
We developed and introduced into clinical practice a leaflet to improve the delivery of information to patients before obtaining their consent to anaesthesia. The amount of information needs to be what a "reasonable" patient thinks appropriate; therefore we tested patients' responses to three levels of information: "full" disclosure, "standard" disclosure (as contained in our leaflet) and "minimal" disclosure. Forty-five patients scheduled to undergo cardiac surgery were enrolled in the study. None of the information sheets caused a significant change in state anxiety score and only the "full" disclosure significantly increased knowledge about anaesthesia (P = 0.016). All leaflets were easy to understand. When only one leaflet was provided 64-73% of patients thought the content was "just right", whereas when all three leaflets were viewed together, 63% of patients thought the "minimal" leaflet withheld too much information.
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Effect of the Mitral Valve's Anterior Leaflet on Axisymmetry of Transmitral Vortex Ring.
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.
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Sripathi, Vangipuram Canchi; Kumar, Ramarathnam Krishna; Balakrishnan, Komarakshi R
2004-03-01
This study aims to find the fundamental differences in the mechanism of opening and closing of a normal aortic valve and a valve with a stiff root, using a dynamic finite element model. A dynamic, finite element model with time varying pressure was used in this study. Shell elements with linear elastic properties for the leaflet and root were used. Two different cases were analyzed: (1) normal leaflets inside a compliant root, and (2) normal leaflets inside a stiff root. A compliant aortic root contributes substantially to the smooth and symmetrical leaflet opening with minimal gradients. In contrast, the leaflet opening inside a stiff root is delayed, asymmetric, and wrinkled. However, this wrinkling is not associated with increased leaflet stresses. In compliant roots, the effective valve orifice area can substantially increase because of increased root pressure and transvalvular gradients. In stiff roots this effect is strikingly absent. A compliant aortic root contributes substantially to smooth and symmetrical leaflet opening with minimal gradients. The compliance also contributes much to the ability of the normal aortic valve to increase its effective valve orifice in response to physiologic demands of exercise. This effect is strikingly absent in stiff roots.
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Martin, Caitlin; Sun, Wei
2016-01-01
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% to 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. PMID:27734178
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Neethling, W M; Papadimitriou, J M; Swarts, E; Hodge, A J
2000-06-01
Valve related factors and patient related factors are responsible for calcification of valvular bioprostheses. Recent studies showed different donor and recipient species have different influences on the total calcification rate of bioprostheses. This study was performed to evaluate and compare Kangaroo aortic valve leaflets with porcine aortic valve leaflets. Experimental design. Prospective study. Setting. Cardio-thoracic experimental research of a university department. Glutaraldehyde-fixed Kangaroo and porcine valve leaflets were evaluated in vitro according to valve geometry (internal diameter and leaflet thickness), morphology (light and electron microscopy) and tensile strength. In vivo evaluation consisted of implantation in a rat model for 8 weeks, Von Kossa stain for calcium and atomic absorption spectrophotometry for total extractable calcium content. Kangaroo valves indicated a smaller internal valve diameter as well as a thinner valve leaflet (p<0.01, ANOVA) at corresponding body weight, less proteoglycan spicules in the fibrosa, increased elasticity (p<0.05) and low calcification potential (p<0.01, confidence interval 95%). Kangaroo aortic valve leaflets have different valvular qualities compared to porcine valve tissue. Kangaroo valve leaflets are significantly superior to porcine valve leaflets as far as calcification is concerned. These results are encouraging and suggest further in vivo evaluation in a larger animal model before clinical application can be considered.
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IP3-mediated gating mechanism of the IP3 receptor revealed by mutagenesis and X-ray crystallography.
Hamada, Kozo; Miyatake, Hideyuki; Terauchi, Akiko; Mikoshiba, Katsuhiko
2017-05-02
The inositol 1,4,5-trisphosphate (IP 3 ) receptor (IP 3 R) is an IP 3 -gated ion channel that releases calcium ions (Ca 2+ ) from the endoplasmic reticulum. The IP 3 -binding sites in the large cytosolic domain are distant from the Ca 2+ conducting pore, and the allosteric mechanism of how IP 3 opens the Ca 2+ channel remains elusive. Here, we identify a long-range gating mechanism uncovered by channel mutagenesis and X-ray crystallography of the large cytosolic domain of mouse type 1 IP 3 R in the absence and presence of IP 3 Analyses of two distinct space group crystals uncovered an IP 3 -dependent global translocation of the curvature α-helical domain interfacing with the cytosolic and channel domains. Mutagenesis of the IP 3 R channel revealed an essential role of a leaflet structure in the α-helical domain. These results suggest that the curvature α-helical domain relays IP 3 -controlled global conformational dynamics to the channel through the leaflet, conferring long-range allosteric coupling from IP 3 binding to the Ca 2+ channel.
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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.
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Rapid pannus formation after few months of obstructing aortic mechanical prosthesis.
Al-Alao, Bassel; Simoniuk, Urszula; Heron, Brian; Parissis, Haralabos
2015-11-01
We report a rare case of a prosthetic aortic valve obstruction due to pannus formation only 3 months following aortic and mitral valve replacement. Fragments of asymmetrical pannus formation affected one of the leaflets of the bi-leaflet mechanical valve; the leaflet appeared immobile due to pannus ingrowth into the mechanical skeleton resulting in encroachment of the leaflet, which in turn became immobile. The patient successfully underwent emergency redo-aortic valve replacement.
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Rabbah, Jean-Pierre; Saikrishnan, Neelakantan; Yoganathan, Ajit P.
2012-01-01
Numerical models of the mitral valve have been used to elucidate mitral valve function and mechanics. These models have evolved from simple two-dimensional approximations to complex three-dimensional fully coupled fluid structure interaction models. However, to date these models lack direct one-to-one experimental validation. As computational solvers vary considerably, experimental benchmark data are critically important to ensure model accuracy. In this study, a novel left heart simulator was designed specifically for the validation of numerical mitral valve models. Several distinct experimental techniques were collectively performed to resolve mitral valve geometry and hemodynamics. In particular, micro-computed tomography was used to obtain accurate and high-resolution (39 µm voxel) native valvular anatomy, which included the mitral leaflets, chordae tendinae, and papillary muscles. Threedimensional echocardiography was used to obtain systolic leaflet geometry for direct comparison of resultant leaflet kinematics. Stereoscopic digital particle image velocimetry provided all three components of fluid velocity through the mitral valve, resolved every 25 ms in the cardiac cycle. A strong central filling jet was observed during peak systole, with minimal out-of-plane velocities (V~0.6m/s). In addition, physiologic hemodynamic boundary conditions were defined and all data were synchronously acquired through a central trigger. Finally, the simulator is a precisely controlled environment, in which flow conditions and geometry can be systematically prescribed and resultant valvular function and hemodynamics assessed. Thus, these data represent the first comprehensive database of high fidelity experimental data, critical for extensive validation of mitral valve fluid structure interaction simulations. PMID:22965640
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Deformation Differences between Tricuspid and Bicuspid Aortic Valves in Vitro
NASA Astrophysics Data System (ADS)
Szeto, Kai; Rodriguez-Rodriguez, Javier; Pastuszko, Peter; Nigam, Vishal; Lasheras, Juan C.
2011-11-01
It has been shown in clinical studies that patients with congenital bicuspid aortic valves (CBAVs) develop degenerative calcification of the leaflets at young ages compared to patients with the normal tricuspid aortic valves (TAVs). It has been hypothesized that the asymmetrical geometry of the leaflets in CBAVs, flow shear stresses (SS), disturbed flow, and excessive strain rate levels are possible causes for the early calcification and stenosis. Central to the validation of this hypothesis is the need to quantify the differences in strain rate levels between the BAVs and TAVs. We simulate the CBAVs by surgically stitching two of the leaflets of a porcine aortic valve together. To quantify strain differences, we performed in-vitro experiments in both trileaflet and bileaflet valves by tracking the motion of small ink dots marked on each leaflet surface. We then used phase-locked stereo photogrammetry to reconstruct at each instant of time the 3D surface of the leaflets and measure the strain rates in both radial and circumferential directions during the whole cardiac cycle. Our results indicate that the total strain rate of the simulated BAVs is about 15 to 20% higher than the normal leaflets of TAVs at systole. In the BAVs' case, the fused leaflet stretches radially up to 25% higher than the reference length. The excessive stretching in both directions in the fused leaflet results in large changes in the flow patterns and associated wall SS.
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Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets.
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.
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Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets
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
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Xie, Xu-jing; Liao, Sheng-jie; Wu, Yue-heng; Lu, Cong; Zhu, Ping; Fei, Hong-wen; Xiao, Xue-jun; Huang, Huan-lei
2016-02-01
Outcomes of tricuspid valve replacement are poor, partly due to right heart remodelling. The research on its underlying mechanisms is hampered by a lack of animal models of tricuspid regurgitation (TR). Our objective was to create a reproducible and clinically compatible TR animal model to study right heart remodelling caused by TR. Fourteen juvenile male Beagle dogs were divided randomly into an intervention group (n = 11) and a sham-operated control group (n = 3). The intervention group underwent thoracotomy and right atrial incision following superior and inferior vena caval occlusion. The anterior leaflet, together with the chordae, of the tricuspid valve was resected in eight dogs ('one leaflet' group), whereas both anterior and posterior leaflets, together with the chordae, were resected in three dogs ('two leaflets' group). The right atrium and chest were then closed. The control group underwent the same procedure, except leaflet resection. One dog from the 'two leaflets' group and one control dog were sacrificed and autopsy was performed at 12 months post-surgery. All dogs survived over the 1-year observation period postoperatively. TR grade IV occurred immediately postoperatively in the 'one leaflet' group, and TR grade IV plus in the 'two leaflets' group. The overall procedure lasted 30-40 min, and the mean time of vena caval occlusion was 87 ± 10 s. Central venous pressure increased from 6 ± 1.2 at baseline to 13 ± 1.7 mmHg (P < 0.01). By 12 months after TR creation, both in the 'one leaflet' group and in the 'two leaflets' group, the right atrial area, tricuspid annular diameter and right ventricular index of myocardial performance increased significantly, right ventricular fractional area change and tricuspid annular plane systolic excursion decreased significantly. Autopsy of the intervention dog revealed oedema, ascites and cirrhosis. Our surgical technique to create a TR animal model was reproducible with high success and survival rates. This animal model would prove suitable to investigate the mechanisms of right heart remodelling. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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Heberle, Frederick A.; Marquardt, Drew; Doktorova, Milka; ...
2016-04-29
Cell membranes possess a complex three-dimensional architecture, including nonrandom lipid lateral organization within the plane of a bilayer leaflet, and compositional asymmetry between the two leaflets. As a result, delineating the membrane structure–function relationship has been a highly challenging task. Even in simplified model systems, the interactions between bilayer leaflets are poorly understood, due in part to the difficulty of preparing asymmetric model membranes that are free from the effects of residual organic solvent or osmotic stress. To address these problems, we have modified a technique for preparing asymmetric large unilamellar vesicles (aLUVs) via cyclodextrin-mediated lipid exchange in order tomore » produce tensionless, solvent-free aLUVs suitable for a range of biophysical studies. Leaflet composition and structure were characterized using isotopic labeling strategies, which allowed us to avoid the use of bulky labels. NMR and gas chromatography provided precise quantification of the extent of lipid exchange and bilayer asymmetry, while small-angle neutron scattering (SANS) was used to resolve bilayer structural features with subnanometer resolution. Isotopically asymmetric POPC vesicles were found to have the same bilayer thickness and area per lipid as symmetric POPC vesicles, demonstrating that the modified exchange protocol preserves native bilayer structure. Partial exchange of DPPC into the outer leaflet of POPC vesicles produced chemically asymmetric vesicles with a gel/fluid phase-separated outer leaflet and a uniform, POPC-rich inner leaflet. SANS was able to separately resolve the thicknesses and areas per lipid of coexisting domains, revealing reduced lipid packing density of the outer leaflet DPPC-rich phase compared to typical gel phases. Lastly, our finding that a disordered inner leaflet can partially fluidize ordered outer leaflet domains indicates some degree of interleaflet coupling, and invites speculation on a role for bilayer asymmetry in modulating membrane lateral organization.« less
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An assessment of nutritional information in oral health education leaflets.
Morgan, M Z; McFarlane, E; Stewart, K F; Hunter, M L; Fairchild, R M
2010-06-01
Dental caries prevalence in UK children remains high and obesity, closely linked to Type 2 diabetes, is rising. Literature suggests that dentists may not give dietary advice due to a lack of clear and consistent guidelines. The aim of the study was to determine whether oral health education leaflets with a food and nutritional focus conform to existing UK national nutritional guidelines from the Department of Health (DoH), the Food Standards Agency (FSA) and the Committee on Medical Aspects of Food and Nutrition Policy (COMA). A sample of 30 information leaflets, aimed at parents and children aged 3-16 years, was sourced during the winter of 2005-2006. A qualitative content analysis was carried out to identify key recommendations on type, frequency and quantity of food and drink and general diet-related health advice. Most leaflets (21) promoted milk and water in agreement with nutritional guidelines. Timing of sugary food and drink to mealtimes (25) and decreasing frequency of 'sugary' e.g. non-milk extrinsic (NME) sugar containing foods (22) and drinks (25) reflected guidelines. Inconsistencies were, however, recorded in the leaflets. Five leaflets advised that frequency of consumption rather than the amount of sugary food or drink was important for oral health. This conflicts with nutritional guidelines, aimed at tackling obesity, to decrease both amount and frequency. There was conflicting advice on healthy snacks. Crisps were presented as 'healthy' by two leaflets; another two advised against snacking on dried fruit, conflicting with FSA guidelines that dried fruit contributes to "5 a day". Sixteen leaflets promoted cheese as 'healthy' with no limits on portion size; this could conflict with nutritional guidelines associated with percentage energy contribution of saturated fat to the diet. While there was agreement between leaflet content and nutritional guidelines, there were inconsistencies. Dental professionals should acknowledge these when selecting leaflets for lay dissemination.
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Consent information leaflets – readable or unreadable?
Graham, Caroline; Reynard, John M; Turney, Benjamin W
2016-01-01
Objective The objective of this article is to assess the readability of leaflets about urological procedures provided by the British Association of Urological Surgeons (BAUS) to evaluate their suitability for providing information. Methods Information leaflets were assessed using three measures of readability: Flesch Reading Ease, Flesch-Kincaid and Simple Measure of Gobbledygook (SMOG) grade formulae. The scores were compared with national literacy statistics. Results Relatively good readability was demonstrated using the Flesch Reading Ease (53.4–60.1) and Flesch-Kincaid Grade Level (6.5–7.6) methods. However, the average SMOG index (14.0–15.0) for each category suggests that the majority of the leaflets are written above the reading level of an 18-year-old. Using national literacy statistics, at least 43% of the population will have significant difficultly understanding the majority of these leaflets. Conclusions The results suggest that comprehension of the leaflets provided by the BAUS is likely to be poor. These leaflets may be used as an adjunct to discussion but it is essential to ensure that all the information necessary to make an informed decision has been conveyed in a way that can be understood by the patient. PMID:27867520
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Alavi, S. Hamed; Ruiz, Victor; Krasieva, Tatiana; Botvinick, Elliot L.; Kheradvar, Arash
2014-01-01
When implanted inside the body, bioprosthetic heart valve leaflets experience a variety of cyclic mechanical stresses such as shear stress due to blood flow when the valve is open, flexural stress due to cyclic opening and closure of the valve, and tensile stress when the valve is closed. These types of stress lead to a variety of failure modes. In either a natural valve leaflet or a processed pericardial tissue leaflet, collagen fibers reinforce the tissue and provide structural integrity such that the very thin leaflet can stand enormous loads related to cyclic pressure changes. The mechanical response of the leaflet tissue greatly depends on collagen fiber concentration, characteristics, and orientation. Thus, understating the microstructure of pericardial tissue and its response to dynamic loading is crucial for the development of more durable heart valve, and computational models to predict heart valves’ behavior. In this work, we have characterized the 3D collagen fiber arrangement of bovine pericardial tissue leaflets in response to a variety of different loading conditions under Second-Harmonic Generation Microscopy. This real-time visualization method assists in better understanding of the effect of cyclic load on collagen fiber orientation in time and space. PMID:23180029
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Iatrogenic Aortic Valve Perforation after Ventricular Septal Defect Repair
Ren, Chonglei; Wang, Mingyan; Wang, Yao; Gao, Changqing
2017-01-01
Iatrogenic aortic valve (AV) perforation during non-aortic cardiac operations is a rare complication. The suture-related inadvertent injury to an AV leaflet can produce leaflet perforation with aortic regurgitation after ventricular septal defect repair (VSDR). We report three consecutive patients who had iatrogenic aortic leaflet perforation during VSDR in other hospitals and referred to our hospital for reoperation. In all three cases, the perforated AV leaflets were preserved and repaired by autologous pericardial patch or direct local closure. PMID:29057770
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Patel, Harshali K; Bapat, Shweta S; Bhansali, Archita H; Sansgiry, Sujit S
2018-01-01
The objective of this study was to develop a one-page (1-page) prescription drug information leaflet (PILs) and assess their impact on the information processing variables, across 2 levels of patient involvement. One-page PILs were developed using cognitive principles to lower mental effort and improve comprehension. An experimental, 3 × 2 repeated measures study was conducted to determine the impact of cognitive effort, manipulated using leaflet type on comprehension across 2 levels (high/low) of patient involvement. Adults (≥18 years) in a university setting in Houston were recruited for the study. Each participant was exposed to 3 different types of prescription drug information leaflet (the current practice, preexisting 1-page text-only, and 1-page PILs) for the 3 drugs (Celebrex, Ventolin HFA, Prezista) for a given involvement scenario. A prevalidated survey instrument was used to measure product knowledge, attitude toward leaflet, and intention to read. Multivariate analysis of variance indicated significant positive effect of cognitive effort, involvement, and their interaction effect across all measured variables. Mean scores for product knowledge, attitude toward leaflet, and intention to read were highest for PILs ( P < .001), indicating that PILs exerted lowest cognitive effort. Univariate and post hoc analysis indicate that product knowledge significantly increases with high involvement. Patients reading PILs have higher comprehension compared with the current practice and text-only prototype leaflets evaluated. Higher levels of involvement further improve participant knowledge about the drug, increase their intention to read the leaflet, and change their attitude toward the leaflet. Implementation of PILs would improve information processing for consumers by reducing their cognitive effort.
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Calik, Eyup Serhat; Limandal, Husnu Kamil; Arslan, Umit; Tort, Mehmet; Yildiz, Ziya; Bayram, Ednan; Dag, Ozgur; Kaygin, Mehmet Ali; Erkut, Bilgehan
2015-12-14
Leaflet escape of prosthetic valve is rare but potentially life threatening. Early diagnosis is essential on account of avoiding mortality, and emergency surgical correction is compulsory. This complication has previously been reported for both monoleaflet and bileaflet valve models. A 30-year-old man who had undergone mitral valve replacement with a bileaflet valve 8 years prior at another center was admitted with acute-onset with cardiogenic shock as an emergency case. Transthoracic echocardiograms showed acute-starting severe mitral regurgitation associated with prosthetic mitral valve. There was a suspicious finding of a single prosthetic mitral leaflet. But the problem related with the valve wasn't specifically determined. The patient underwent emergent surgery for replacement of the damaged prosthetic valves immediately. There was no tissue impingement and thrombosis, one of the two leaflets was absent, and there were no signs of endocarditis or pannus formation in the prosthetic valve. The missing leaflet could not be found within the cardiac cavity. The abdominal fluoroscopic study and plain radiography were unable to detect the escaped leaflet during surgery. The damaged valve was removed and a replacement 29 mm bileaflet mechanical valve was inserted by right lateral thoracotomy. After post-operative week one, the abdominal computed tomography scan and the ultrasound showed the escaped leaflet in the left femoral artery. Fifteen days after the surgery the escaped leaflet was removed safely from the left femoral artery and the patient made a complete recovery. The escaped leaflet showed a fracture of one of the pivot systems caused by structural failure. Early cardiac surgery should be applied because of life-threatening problems.
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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 to the length over the three studied years (P=.002 in 2007, P=.007 in 2010, P=.009 in 2013). Linear correlation was observed between the readability indexes (SMOG grade and Flesch-Kincaid grade level: r2=.92; SMOG grade and Szigriszt’s perspicuity index: r2=.81; Flesch-Kincaid grade level and Szigriszt’s perspicuity index: r2=.95), but not between the readability indexes and the length (length and SMOG grade: r2=.05; length and Flesch-Kincaid grade level: r2=.03; length and Szigriszt’s perspicuity index: r2=.02). Conclusions There was no improvement in the readability of the package leaflets studied between 2007 and 2013 despite the European Commission’s 2009 guideline on the readability of package leaflets. The results obtained from the different readability formulas coincided from a qualitative point of view. Efforts to improve the readability of package leaflets for biological medicines are required to promote the understandability and accessibility of this online health information by patients and thereby contribute to the appropriate use of medicines and medicine safety. PMID:27226241
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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 years (P=.002 in 2007, P=.007 in 2010, P=.009 in 2013). Linear correlation was observed between the readability indexes (SMOG grade and Flesch-Kincaid grade level: r(2)=.92; SMOG grade and Szigriszt's perspicuity index: r(2)=.81; Flesch-Kincaid grade level and Szigriszt's perspicuity index: r(2)=.95), but not between the readability indexes and the length (length and SMOG grade: r(2)=.05; length and Flesch-Kincaid grade level: r(2)=.03; length and Szigriszt's perspicuity index: r(2)=.02). There was no improvement in the readability of the package leaflets studied between 2007 and 2013 despite the European Commission's 2009 guideline on the readability of package leaflets. The results obtained from the different readability formulas coincided from a qualitative point of view. Efforts to improve the readability of package leaflets for biological medicines are required to promote the understandability and accessibility of this online health information by patients and thereby contribute to the appropriate use of medicines and medicine safety.
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Melanocyte pigmentation stiffens murine cardiac tricuspid valve leaflet
Balani, Kantesh; Brito, Flavia C.; Kos, Lidia; Agarwal, Arvind
2009-01-01
Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic nature, estimation of the in situ stiffness measurement becomes a challenging task. Therefore, quasi-static and nanodynamic mechanical analysis of the leaflets of the mouse tricuspid valve is performed in the current work. The mechanical properties along the leaflet vary with the degree of pigmentation. Pigmented regions of the valve leaflet that contain melanocytes displayed higher storage modulus (7–10 GPa) than non-pigmented areas (2.5–4 GPa). These results suggest that the presence of melanocytes affects the viscoelastic properties of the mouse atrioventricular valves and are important for their proper functioning in the organism. PMID:19586956
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Kao, Wen-Yuan; Lin, Bai-Ling
2010-09-01
Diurnal phototropism has not been reported in ferns. In this study we found that the four leaflets of the amphibious fern Marsilea quadrifolia are capable of adjusting their leaflet angle and leaflet azimuth in response to changes in the position of the sun's direct beam, exhibiting more diaphototropic movements (orienting the plane of the lamina perpendicular to incident light) in the morning and late afternoon, and more paraphototropic movements (orienting the plane of the lamina parallel to incident light) at noon. In addition, by cutting off the leaflet lamina and covering portions of leaflets with black tape, the junction between the leaflet and petiole was found to be responsible for light reception. Among the light spectrum investigated, blue light was the most effective at inducing diaphototropism. The role of diurnal phototropism in enhancing carbon return and ameliorating photoinhibition was also evaluated. It was concluded that diurnal phototropic leaf movement represents one of the plastic responses enabling this amphibious fern to grow under terrestrial conditions.
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Late leaflet fracture and embolization of a Duromedics mitral prosthesis.
Sudo, K; Sasagawa, N; Ide, H; Nunokawa, M; Fujiki, T; Tonari, K
2000-08-01
A case of leaflet fracture and embolization of a mitral prosthetic valve is described. A 54-year-old man had received mitral valve replacement with an Edwards-Duromedics 29M prosthetic valve, at 10 years ago. Emergency mitral valve replacement was performed because the patient had severe congestive left heart failure with severe acute mitral regurgitation caused by a fracture in one of the mitral valve leaflets. The leaflet, which was fractured into 2 pieces, was removed from the right common iliac artery at 3 months after valve replacement. Visual inspection revealed that the leaflet contained a midline fracture. The fracture originated within a cavitary erosion pit near the major radius of the leaflet. The patient recovered from acute renal failure, requiring hemodialysis for 80 days, and is currently without complaints. We have used a Duromedics mitral valve in 11 patients, from April 1987 to April 1988. No subsequent valve failure has occurred. The diagnosis, treatment and cause of a mechanical valve fracture are discussed.
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Jalaei, Bahram; Azmi, Mohd Hafiz Afifi Mohd; Zakaria, Mohd Normani
2018-05-17
Binaurally evoked auditory evoked potentials have good diagnostic values when testing subjects with central auditory deficits. The literature on speech-evoked auditory brainstem response evoked by binaural stimulation is in fact limited. Gender disparities in speech-evoked auditory brainstem response results have been consistently noted but the magnitude of gender difference has not been reported. The present study aimed to compare the magnitude of gender difference in speech-evoked auditory brainstem response results between monaural and binaural stimulations. A total of 34 healthy Asian adults aged 19-30 years participated in this comparative study. Eighteen of them were females (mean age=23.6±2.3 years) and the remaining sixteen were males (mean age=22.0±2.3 years). For each subject, speech-evoked auditory brainstem response was recorded with the synthesized syllable /da/ presented monaurally and binaurally. While latencies were not affected (p>0.05), the binaural stimulation produced statistically higher speech-evoked auditory brainstem response amplitudes than the monaural stimulation (p<0.05). As revealed by large effect sizes (d>0.80), substantive gender differences were noted in most of speech-evoked auditory brainstem response peaks for both stimulation modes. The magnitude of gender difference between the two stimulation modes revealed some distinct patterns. Based on these clinically significant results, gender-specific normative data are highly recommended when using speech-evoked auditory brainstem response for clinical and future applications. The preliminary normative data provided in the present study can serve as the reference for future studies on this test among Asian adults. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.
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Desmedt, J E; Ozaki, I
1991-01-01
A method using a DC servo motor is described to produce brisk angular movements at finger interphalangeal joints in humans. Small passive flexions of 2 degrees elicited sizable somatosensory evoked potentials (SEPs) starting with a contralateral positive P34 parietal response thought to reflect activation of a radial equivalent dipole generator in area 2 which receives joint inputs. By contrast, electric stimulation of tactile (non-joint) inputs from the distal phalanx evoked the usual contralateral negative N20 reflecting a tangential equivalent dipole generator in area 3b. Finger joint inputs also evoked a precentral positivity equivalent to the P22 of motor area 4, and a large frontal negativity equivalent to N30. It is suggested that natural stimulation allows human SEP components to be differentiated in conjunction with distinct cortical somatotopic projections.
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Developing leaflets to give dental health advice to Aboriginal families with young children.
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.
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Svarstad, Bonnie L; Bultman, Dara C; Mount, Jeanine K; Tabak, Ellen R
2003-01-01
To develop three tools for assessing the quality of written information provided with new prescriptions in community pharmacies and to identify pharmacy, pharmacist, and patient characteristics associated with the dissemination and quality of that information. Observational study. Regression techniques were used to analyze the influence of pharmacy, pharmacist, and shopper (acting as patient) characteristics on outcome measures. Trained shoppers (acting as patients) visited 306 randomly selected pharmacies in 8 states. Each shopper presented three prescriptions, answered questions according to a standard scenario, accepted the information offered, and paid for the prescriptions. Percentage of shoppers receiving any written information; quality of written information as judged by an expert panel using explicit criteria. Shoppers received an information leaflet with 87% of the 918 prescriptions dispensed. Although most leaflets provided unbiased information, leaflet length and quality of information varied greatly. A majority of leaflets did not include adequate information about contraindications, precautions, and how to avoid harm. Shoppers were more likely to receive leaflets in chain pharmacies and pharmacies with more staff. Information quality also was higher in chain pharmacies. Shopper and pharmacist demographic characteristics were unrelated to the level or quality of written information after controlling for other factors. The provision of patient leaflets is becoming a routine practice in the states studied. However, most leaflets do not meet quality criteria. It is important for pharmacists to become familiar with criteria for evaluating these leaflets and to take necessary action to improve their quality.
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Prosthetic Mitral Valve Leaflet Escape
Kim, Darae; Hun, Sin Sang; Cho, In-Jeong; Shim, Chi-Young; Ha, Jong-Won; Chung, Namsik; Ju, Hyun Chul; Sohn, Jang Won
2013-01-01
Leaflet escape of prosthetic valve is rare but potentially life threatening. It is essential to make timely diagnosis in order to avoid mortality. Transesophageal echocardiography and cinefluoroscopy is usually diagnostic and the location of the missing leaflet can be identified by computed tomography (CT). Emergent surgical correction is mandatory. We report a case of fractured escape of Edward-Duromedics mitral valve 27 years after the surgery. The patient presented with symptoms of acute decompensated heart failure and cardiogenic shock. She was instantly intubated and mechanically ventilated. After prompt evaluation including transthoracic echocardiography and CT, the escape of the leaflet was confirmed. The patient underwent emergent surgery for replacement of the damaged prosthetic valves immediately. Eleven days after the surgery, the dislodged leaflet in iliac artery was removed safely and the patient recovered well. PMID:23837121
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Kobza, R; Kurz, D J; Oechslin, E N; Prêtre, R; Zuber, M; Vogt, P; Jenni, R
2004-03-01
To define the entity of tricuspid regurgitation caused by tethering of the tricuspid valve leaflets by aberrant tendinous chords. Retrospective study. Tertiary care centre (university teaching hospital). 10 patients with unexplained severe tricuspid regurgitation. The last 13 500 echocardiographic studies from our facility were reviewed to identify patients with severe unexplained tricuspid regurgitation. Tethering was defined by the presence of aberrant tendinous chords to the tricuspid valve leaflets limiting the mobility of the tricuspid leaflet and resulting in incomplete coaptation and apical displacement of the regurgitant jet origin. Aberrant tendinous chords were defined as those inserting at the clear zone of the tricuspid leaflet and not originating from the papillary muscle. Patients fulfilling the diagnostic criteria for Ebstein's anomaly were excluded. 10 patients with aberrant tendinous chords tethering one or more tricuspid valve leaflets were identified. There were short non-aberrant tendinous chords in seven patients, five of whom also had right ventricular or tricuspid annulus dilatation. Tethering of the tricuspid valve leaflets by aberrant tendinous chords can be the sole mechanism of congenital tricuspid regurgitation. It is often associated with short non-aberrant tendinous chords, which may develop secondary to right ventricular or tricuspid annulus dilatation. Awareness of tethering as a cause of tricuspid regurgitation may be important in planning reconstructive surgery.
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Promoting chlamydia screening with posters and leaflets in general practice--a qualitative study.
Freeman, Elaine; Howell-Jones, Rebecca; Oliver, Isabel; Randall, Sarah; Ford-Young, William; Beckwith, Philippa; McNulty, Cliodna
2009-10-12
General practice staff are reluctant to discuss sexual health opportunistically in all consultations. Health promotion materials may help alleviate this barrier. Chlamydia screening promotion posters and leaflets, produced by the English National Chlamydia Screening Programme (NCSP), have been available to general practices, through local chlamydia screening offices, since its launch. In this study we explored the attitudes of general practice staff to these screening promotional materials, how they used them, and explored other promotional strategies to encourage chlamydia screening. Twenty-five general practices with a range of screening rates, were purposively selected from six NCSP areas in England. In focus groups doctors, nurses, administrative staff and receptionists were encouraged to discuss candidly their experiences about their use and opinions of posters, leaflets and advertising to promote chlamydia screening. Researchers observed whether posters and leaflets were on display in reception and/or waiting areas. Data were collected and analysed concurrently using a stepwise framework analytical approach. Although two-thirds of screening practices reported that they displayed posters and leaflets, they were not prominently displayed in most practices. Only a minority of practices reported actively using screening promotional materials on an ongoing basis. Most staff in all practices were not following up the advertising in posters and leaflets by routinely offering opportunistic screening to their target population. Some staff in many practices thought posters and leaflets would cause offence or embarrassment to their patients. Distribution of chlamydia leaflets by receptionists was thought to be inappropriate by some practices, as they thought patients would be offended when being offered a leaflet in a public area. Practice staff suggested the development of pocket-sized leaflets. The NCSP should consider developing a range of more discrete but eye catching posters and small leaflets specifically to promote chlamydia screening in different scenarios within general practice; coordinators should audit their use. Practice staff need to discuss, with their screening co-ordinator, how different practice staff can promote chlamydia screening most effectively using the NCSP promotional materials, and change them regularly so that they do not loose their impact. Education to change all practice staff's attitudes towards sexual health is needed to reduce their worries about displaying the chlamydia materials, and how they may follow up the advertising up with a verbal offer of screening opportunistically to 15-24 year olds whenever they visit the practice.
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Promoting chlamydia screening with posters and leaflets in general practice - a qualitative study
Freeman, Elaine; Howell-Jones, Rebecca; Oliver, Isabel; Randall, Sarah; Ford-Young, William; Beckwith, Philippa; McNulty, Cliodna
2009-01-01
Background General practice staff are reluctant to discuss sexual health opportunistically in all consultations. Health promotion materials may help alleviate this barrier. Chlamydia screening promotion posters and leaflets, produced by the English National Chlamydia Screening Programme (NCSP), have been available to general practices, through local chlamydia screening offices, since its launch. In this study we explored the attitudes of general practice staff to these screening promotional materials, how they used them, and explored other promotional strategies to encourage chlamydia screening. Methods Twenty-five general practices with a range of screening rates, were purposively selected from six NCSP areas in England. In focus groups doctors, nurses, administrative staff and receptionists were encouraged to discuss candidly their experiences about their use and opinions of posters, leaflets and advertising to promote chlamydia screening. Researchers observed whether posters and leaflets were on display in reception and/or waiting areas. Data were collected and analysed concurrently using a stepwise framework analytical approach. Results Although two-thirds of screening practices reported that they displayed posters and leaflets, they were not prominently displayed in most practices. Only a minority of practices reported actively using screening promotional materials on an ongoing basis. Most staff in all practices were not following up the advertising in posters and leaflets by routinely offering opportunistic screening to their target population. Some staff in many practices thought posters and leaflets would cause offence or embarrassment to their patients. Distribution of chlamydia leaflets by receptionists was thought to be inappropriate by some practices, as they thought patients would be offended when being offered a leaflet in a public area. Practice staff suggested the development of pocket-sized leaflets. Conclusion The NCSP should consider developing a range of more discrete but eye catching posters and small leaflets specifically to promote chlamydia screening in different scenarios within general practice; coordinators should audit their use. Practice staff need to discuss, with their screening co-ordinator, how different practice staff can promote chlamydia screening most effectively using the NCSP promotional materials, and change them regularly so that they do not loose their impact. Education to change all practice staff's attitudes towards sexual health is needed to reduce their worries about displaying the chlamydia materials, and how they may follow up the advertising up with a verbal offer of screening opportunistically to 15-24 year olds whenever they visit the practice. PMID:19821964
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AUDITORY NUCLEI: DISTINCTIVE RESPONSE PATTERNS TO WHITE NOISE AND TONES IN UNANESTHETIZED CATS.
GALIN, D
1964-10-09
Electrical responses to "white" noise and tonal stimuli were recorded from unanesthetized cats with permanently implanted bipolar electrodes. The cochlear nucleus, inferior colliculus, and medial geniculate each showed distinctive patterns of evoked activity. White noise and tones produced qualitatively different types of response. A decrease in activity characterized the response of the inferior colliculus to tonal stimuli.
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Identification of spinal circuits involved in touch-evoked dynamic mechanical pain
Cheng, Longzhen; Duan, Bo; Huang, Tianwen; Zhang, Yan; Chen, Yangyang; Britz, Olivier; Garcia-Campmany, Lidia; Ren, Xiangyu; Vong, Linh; Lowell, Bradford B.; Goulding, Martyn; Wang, Yun; Ma, Qiufu
2017-01-01
Mechanical hypersensitivity is a debilitating symptom associated with millions of chronic pain patients. It exists in distinct forms, including brush-evoked dynamic and filament-evoked punctate. Here we report that dynamic mechanical hypersensitivity induced by nerve injury or inflammation was compromised in mice with ablation of spinal VT3Lbx1 neurons defined by coexpression of VGLUT3Cre and Lbx1Flpo, as indicated by the loss of brush-evoked nocifensive responses and conditional place aversion. Electrophysiological recordings show that VT3Lbx1 neurons form morphine-resistant polysynaptic pathways relaying inputs from low-threshold Aβ mechanoreceptors to lamina I output neurons. Meanwhile, the subset of somatostatin (SOM) lineage neurons preserved in VT3Lbx1 neuron-ablated mice is largely sufficient to mediate von Frey filament-evoked punctate mechanical hypersensitivity, including both morphine-sensitive and morphine-resistant forms. Furthermore, acute silencing of VT3Lbx1 neurons attenuated pre-established dynamic mechanical hypersensitivity induced by nerve injury, suggesting these neurons as a potential cellular target for treating this form of neuropathic pain. PMID:28436981
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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.
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PN FOR CHILDREN - INFORMATION LEAFLET.
Riddell, Rebecca; Lewis, Anthony; Tuthill, David
2016-09-01
To produce a leaflet for parents and carers of children receiving parenteral nutrition (PN) explaining:▸ What PN is▸ Why it is given▸ How it will be given▸ Risks & Complications▸ Other useful information▸ Nutrition team contact informationCurrent practice is for the nutrition team pharmacist to give a verbal account of the above information to parents/carers. It was felt that providing this information in a written format would introduce consisitency and allow parents/carers more time to take information on board. An internet search and discussions with other organisations with paediatric gastroenterology specialists was conduted to see if something similar was in existence. A similar information leaflet to what we hoped to produce was not found. Members of the paediatric nutrition team, which included consultants, nurse specialists, pharmacist and dietician, provided input to the type of information that should be included in the information leaflet. A first draft of the leaflet was produced and shown to the parents of current paediatric PN inpatients. Feedback was received and the leaflet updated following consultation with the nutrition team. Production of a very useful information leaflet for parents/carers, containing all the relevant information and detail. The leaflet uses colour and pictures to aid the transfer of information and makes it more attractive to read. The pharmacist is the main point of contact for the paediatric nutrition team and will be the individual responsible for distributing them. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
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Distribution of the microelastic properties within the human anterior mitral leaflet.
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: ).
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[Parenting Renewal. Leaflet and Lessons for Parents of Adolescents.
ERIC Educational Resources Information Center
Clemson Univ., SC. Cooperative Extension Service.
Instructional materials on parenting skills for parents of adolescents are provided, with teaching guides for extension service agents. Organized as a series of five leaflets followed by five corresponding lessons, leaflets for parents concern: (1) a review of parenting skills and an overview of the course of instruction; (2) evolution:…
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Hill, Reghan J.; Wang, Chih-Ying
2014-01-01
A variety of observations—sometimes controversial—have been made in recent decades when attempting to elucidate the roles of interfacial slip on tracer diffusion in phospholipid membranes. Evans–Sackmann theory (1988) has furnished membrane viscosities and lubrication-film thicknesses for supported membranes from experimentally measured lateral diffusion coefficients. Similar to the Saffman and Delbrück model, which is the well-known counterpart for freely supported membranes, the bilayer is modelled as a single two-dimensional fluid. However, the Evans–Sackman model cannot interpret the mobilities of monotopic tracers, such as individual lipids or rigidly bound lipid assemblies; neither does it account for tracer–leaflet and inter-leaflet slip. To address these limitations, we solve the model of Wang and Hill, in which two leaflets of a bilayer membrane, a circular tracer and supports are coupled by interfacial friction, using phenomenological friction/slip coefficients. This furnishes an exact solution that can be readily adopted to interpret the mobilities of a variety of mosaic elements—including lipids, integral monotopic and polytopic proteins, and lipid rafts—in supported bilayer membranes. PMID:25002822
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Fang, Chuanji; 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
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[TECHNIQUES IN MITRAL VALVE REPAIR VIA A MINIMALLY INVASIVE APPROACH].
Ito, Toshiaki
2016-03-01
In mitral valve repair via a minimally invasive approach, resection of the leaflet is technically demanding compared with that in the standard approach. For resection and suture repair of the posterior leaflet, premarking of incision lines is recommended for precise resection. As an alternative to resection and suture, the leaflet-folding technique is also recommended. For correction of prolapse of the anterior leaflet, neochordae placement with the loop technique is easy to perform. Premeasurement with transesophageal echocardiography or intraoperative measurement using a replica of artificial chordae is useful to determine the appropriate length of the loops. Fine-tuning of the length of neochordae is possible by adding a secondary fixation point on the leaflet if the loop is too long. If the loop is too short, a CV5 Gore-Tex suture can be passed through the loop and loosely tied several times to stack the knots, with subsequent fixation to the edge of the leaflet. Finally, skill in the mitral valve replacement technique is necessary as a back-up for surgeons who perform minimally invasive mitral valve repair.
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Oda, Takeshi; Kato, Seiya; Tayama, Eiki; Fukunaga, Shuji; Akashi, Hidetoshi; Aoyagi, Shigeaki
2009-01-01
A Carpentier-Edwards pericardial (CEP) bioprosthesis was explanted from an 81-year-old woman due to nonstructural dysfunction 9 years after mitral valve replacement. The nonstructural dysfunction produced severe regurgitation in the mitral position. During the surgery, excessive pannus overgrowth was seen on the left ventricular side of the CEP bioprosthesis. Pannus overgrowth was prominent on one leaflet. That leaflet was stiff and shortened due to the excessive overgrowth of pannus. In this patient, the distortion of one leaflet was the main reason for transvalvular leakage of the CEP bioprosthesis in the mitral position. A new CEP bioprosthesis was implanted in the mitral position. Pathological analysis revealed fibrotic pannus with a small amount of cellular material over the leaflets of the resected CEP valve. This change was marked on the distorted leaflet.
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Cheng, Sara Y.; Chou, George; Buie, Creighton; Vaughn, Mark W.; Compton, Campbell; Cheng, Kwan H.
2016-01-01
We used molecular dynamics simulations to explore the effects of asymmetric transbilayer distribution of anionic phosphatidylserine (PS) lipids on the structure of a protein on the membrane surface and subsequent protein–lipid interactions. Our simulation systems consisted of an amyloidogenic, beta-sheet rich dimeric protein (D42) absorbed to the phosphatidylcholine (PC) leaflet, or protein-contact PC leaflet, of two membrane systems: a single-component PC bilayer and double PC/PS bilayers. The latter comprised of a stable but asymmetric transbilayer distribution of PS in the presence of counterions, with a 1-component PC leaflet coupled to a 1-component PS leaflet in each bilayer. The maximally asymmetric PC/PS bilayer had a non-zero transmembrane potential (TMP) difference and higher lipid order packing, whereas the symmetric PC bilayer had a zero TMP difference and lower lipid order packing under physiologically relevant conditions. Analysis of the adsorbed protein structures revealed weaker protein binding, more folding in the N-terminal domain, more aggregation of the N- and C-terminal domains and larger tilt angle of D42 on the PC leaflet surface of the PC/PS bilayer versus the PC bilayer. Also, analysis of protein-induced membrane structural disruption revealed more localized bilayer thinning in the PC/PS versus PC bilayer. Although the electric field profile in the non-protein-contact PS leaflet of the PC/PS bilayer differed significantly from that in the non-protein-contact PC leaflet of the PC bilayer, no significant difference in the electric field profile in the protein-contact PC leaflet of either bilayer was evident. We speculate that lipid packing has a larger effect on the surface adsorbed protein structure than the electric field for a maximally asymmetric PC/PS bilayer. Our results support the mechanism that the higher lipid packing in a lipid leaflet promotes stronger protein–protein but weaker protein–lipid interactions for a dimeric protein on membrane surfaces. PMID:26827904
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Draeger, A; Monastyrskaya, K; Burkhard, F C; Wobus, A M; Moss, S E; Babiychuk, E B
2003-10-15
Muscle contraction implies flexibility in combination with force resistance and requires a high degree of sarcolemmal organization. Smooth muscle cells differentiate largely from mesenchymal precursor cells and gradually assume a highly periodic sarcolemmal organization. Skeletal muscle undergoes an even more striking differentiation programme, leading to cell fusion and alignment into myofibrils. The lipid bilayer of each cell type is further segregated into raft and non-raft microdomains of distinct lipid composition. Considering the extent of developmental rearrangement in skeletal muscle, we investigated sarcolemmal microdomain organization in skeletal and smooth muscle cells. The rafts in both muscle types are characterized by marker proteins belonging to the annexin family which localize to the inner membrane leaflet, as well as glycosyl-phosphatidyl-inositol (GPI)-anchored enzymes attached to the outer leaflet. We demonstrate that the profound structural rearrangements that occur during skeletal muscle maturation coincide with a striking decrease in membrane lipid segregation, downregulation of annexins 2 and 6, and a significant decrease in raft-associated 5'-nucleotidase activity. The relative paucity of lipid rafts in mature skeletal in contrast to smooth muscle suggests that the organization of sarcolemmal microdomains contributes to the muscle-specific differences in stimulatory responses and contractile properties.
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IP3-mediated gating mechanism of the IP3 receptor revealed by mutagenesis and X-ray crystallography
Hamada, Kozo; Miyatake, Hideyuki; Terauchi, Akiko; Mikoshiba, Katsuhiko
2017-01-01
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is an IP3-gated ion channel that releases calcium ions (Ca2+) from the endoplasmic reticulum. The IP3-binding sites in the large cytosolic domain are distant from the Ca2+ conducting pore, and the allosteric mechanism of how IP3 opens the Ca2+ channel remains elusive. Here, we identify a long-range gating mechanism uncovered by channel mutagenesis and X-ray crystallography of the large cytosolic domain of mouse type 1 IP3R in the absence and presence of IP3. Analyses of two distinct space group crystals uncovered an IP3-dependent global translocation of the curvature α-helical domain interfacing with the cytosolic and channel domains. Mutagenesis of the IP3R channel revealed an essential role of a leaflet structure in the α-helical domain. These results suggest that the curvature α-helical domain relays IP3-controlled global conformational dynamics to the channel through the leaflet, conferring long-range allosteric coupling from IP3 binding to the Ca2+ channel. PMID:28416699
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1998-01-01
Leaflets about HIV/AIDS are useful for distributing after talks or counseling sessions, leaving out in settings such as clinics, and mailing out in response to frequently asked questions or inquiries about an organization's services. As is the case with other educational materials, leaflet production involves identification of a target audience, careful planning and pretesting, and attention to design principles. Leaflets can be produced more quickly when adapted from existing materials distributed by other programs. Presented in this article are instructions that should be given to writers, designers, illustrators, or photographers when work is commissioned as well as guidelines for communicating with printers.
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Partial hammock valve: surgical repair in adulthood.
Aramendi, José I; Rodríguez, Miguel A; Voces, Roberto; Pérez, Pedro; Rodrigo, David
2006-09-01
We describe a forme frustrée of hammock valve involving only the posterior mitral leaflet. Three adult patients were referred to surgery with the diagnosis of severe mitral regurgitation due to fibrosis of the posterior mitral leaflet. The final diagnosis was done intraoperatively. In all of them the posterior leaflet was attached to some accessory papillary muscles arranged en palisade, with three to four fused muscle heads producing restrictive leaflet motion in systole. Repair consisted in division of the papillary muscles, patch augmentation, and ring annuloplasty. This previously unreported lesion is congenital but manifests itself in adulthood.
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Kobza, R; Kurz, D J; Oechslin, E N; Prêtre, R; Zuber, M; Vogt, P; Jenni, R
2004-01-01
Objective: To define the entity of tricuspid regurgitation caused by tethering of the tricuspid valve leaflets by aberrant tendinous chords. Design: Retrospective study. Setting: Tertiary care centre (university teaching hospital). Patients: 10 patients with unexplained severe tricuspid regurgitation. Methods: The last 13 500 echocardiographic studies from our facility were reviewed to identify patients with severe unexplained tricuspid regurgitation. Tethering was defined by the presence of aberrant tendinous chords to the tricuspid valve leaflets limiting the mobility of the tricuspid leaflet and resulting in incomplete coaptation and apical displacement of the regurgitant jet origin. Aberrant tendinous chords were defined as those inserting at the clear zone of the tricuspid leaflet and not originating from the papillary muscle. Patients fulfilling the diagnostic criteria for Ebstein’s anomaly were excluded. Results: 10 patients with aberrant tendinous chords tethering one or more tricuspid valve leaflets were identified. There were short non-aberrant tendinous chords in seven patients, five of whom also had right ventricular or tricuspid annulus dilatation. Conclusions: Tethering of the tricuspid valve leaflets by aberrant tendinous chords can be the sole mechanism of congenital tricuspid regurgitation. It is often associated with short non-aberrant tendinous chords, which may develop secondary to right ventricular or tricuspid annulus dilatation. Awareness of tethering as a cause of tricuspid regurgitation may be important in planning reconstructive surgery. PMID:14966058
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Polley, Anirban; Mayor, Satyajit; Rao, Madan, E-mail: madan@rri.res.in, E-mail: madan@ncbs.res.in
2014-08-14
A question of considerable interest to cell membrane biology is whether phase segregated domains across an asymmetric bilayer are strongly correlated with each other and whether phase segregation in one leaflet can induce segregation in the other. We answer both these questions in the affirmative, using an atomistic molecular dynamics simulation to study the equilibrium statistical properties of a 3-component asymmetric lipid bilayer comprising an unsaturated palmitoyl-oleoyl-phosphatidyl-choline, a saturated sphingomyelin, and cholesterol with different composition ratios. Our simulations are done by fixing the composition of the upper leaflet to be at the coexistence of the liquid ordered (l{sub o})-liquid disorderedmore » (l{sub d}) phases, while the composition of the lower leaflet is varied from the phase coexistence regime to the mixed l{sub d} phase, across a first-order phase boundary. In the regime of phase coexistence in each leaflet, we find strong transbilayer correlations of the l{sub o} domains across the two leaflets, resulting in bilayer registry. This transbilayer correlation depends sensitively upon the chain length of the participating lipids and possibly other features of lipid chemistry, such as degree of saturation. We find that the l{sub o} domains in the upper leaflet can induce phase segregation in the lower leaflet, when the latter is nominally in the mixed (l{sub d}) phase.« less
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Efficiency of printed materials in worksite health promotion.
Kishchuk, N; Anbar, F; O'Loughlin, J; Masson, P; Sacks-Silver, G
1991-01-01
Printed health promotion materials are widely believed to be an efficient means of achieving basic health promotion objectives, such as increasing knowledge of risk factors. This study examined the efficiency of cardiovascular health promotion leaflets in reaching employees in a heterogeneous sample of worksites. Two types of distribution were used: copies of the leaflets were either made available centrally or distributed to each individual employee. Interviews were conducted with 272 employees in six worksites. Respondents were asked whether they recognized, had read, and had learned something from the leaflets. Only one-quarter of respondents recognized the leaflets and only 14% stated that they had learned something. The efficiency of the leaflets was therefore much lower than expected. Z-tests for proportions showed that recognition, reading, and learning were significantly greater among those employees who had been given individual copies of the material. Among those who had been given individual copies, 45% reported recognizing the leaflet, 36% reading it, and 23% learning something from it. Among those who had only central access, the respective scores were 11%, 7% and 6%. These results suggest that the potential cost-effectiveness of printed materials such as leaflets and brochures should be weighed against alternative forms of intervention, given specific program objectives and characteristics of the target population. They also suggest that the cost and effort required in organizing the distribution of individual copies may be recouped in greater penetration.
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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…
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Al Bardaweel, Susan; Dashash, Mayssoon
2018-05-10
The early recognition of technology together with great ability to use computers and smart systems have promoted researchers to investigate the possibilities of utilizing technology for improving health care in children. The aim of this study was to compare between the traditional educational leaflets and E-applications in improving oral health knowledge, oral hygiene and gingival health in schoolchildren of Damascus city, Syria. A clustered randomized controlled trial at two public primary schools was performed. About 220 schoolchildren aged 10-11 years were included in this study and grouped into two clusters. Children in Leaflet cluster received oral health education through leaflets, while children in E-learning cluster received oral health education through an E-learning program. A questionnaire was designed to register information related to oral health knowledge and to record Plaque and Gingival indices. Questionnaire administration and clinical assessment were undertaken at baseline, 6 and at 12 weeks of oral health education. Data was analysed using one way repeated measures ANOVA, post hoc Bonferroni test and independent samples t-test. Leaflet cluster (107 participants) had statistically significant better oral health knowledge than E-learning cluster (104 participants) at 6 weeks (P < 0.05) and at 12 weeks (P < 0.05) (Leaflet cluster:100 participants, E-learning cluster:100 participants). The mean knowledge gain compared to baseline was higher in Leaflet cluster than in E-learning cluster. A significant reduction in the PI means at 6 weeks and 12 weeks was observed in both clusters (P < 0.05) when compared to baseline. Children in Leaflet cluster had significantly less plaque than those in E-learning cluster at 6 weeks (P < 0.05) and at 12 weeks (P < 0.05). Similarly, a significant reduction in the GI means at 6 weeks and 12 weeks was observed in both clusters when compared to baseline (P < 0.05). Children in Leaflet cluster had statistically significant better gingival health than E-learning cluster at 6 weeks (P < 0.05) and 12 weeks (P < 0.05). Traditional educational leaflets are an effective tool in the improvement of both oral health knowledge as well as clinical indices of oral hygiene and care among Syrian children. Leaflets can be used in school-based oral health education for a positive outcome. Australian New Zealand Clinical Trials Registry ( ACTRN12618000395235 ), Date registered: 16/03/2018, retrospectively registered.
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Im, Yu-Mi; Park, Chun Soo; Park, Jeong-Jun; Yun, Tae-Jin
2016-03-01
Surgical techniques currently used for the repair of Ebstein's anomaly comprise reconstruction of the tricuspid valve mechanism at the level of the true annulus with or without plication of the atrialized right ventricle. However, performing this procedure for patients with a dysmorphic anterior leaflet (i.e., insufficient leaflet tissue and decreased mobility due to tethering) may necessitate technical modifications. A retrospective review was performed of 31 patients (seven males and 24 females, median age at operation 31 years) with Ebstein's anomaly, who underwent tricuspid valve repair between March 2002 and December 2014. The original Hetzer technique (annulus to annulus approximation) was employed for six patients with a well-formed anterior leaflet. In 25 patients, the tricuspid valve mechanism was restored at the displaced septal leaflet by approximating the anterior leaflet attachment in the true annulus to the displaced septal leaflet attachment in the mid-septum. A bidirectional superior cavopulmonary anastomosis was added in 27 of 31 (87%) patients. No early or late death occurred during the median follow-up of 66 months (1-138 months). Immediate postoperative tricuspid regurgitation was trivial to mild in 22 patients, and the median preoperative, immediate postoperative, and last follow-up tricuspid regurgitation jet areas in 21 adult patients were 23.3 cm2, 10.4 cm2, and 7.0 cm2, respectively. Two patients underwent reoperation at 81 and 119 months postoperatively. Five-year freedom from severe tricuspid regurgitation or reoperation was 93.2%. Restoration of the tricuspid valve mechanism at the level of displaced septal leaflet leads to excellent long-term outcomes. The addition of the bidirectional superior cavopulmonary anastomosis has contributed to the success of this technique. © 2016 Wiley Periodicals, Inc.
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McClinchy, Jane; Dickinson, Angela; Barron, Duncan; Thomas, Hilary
2011-12-01
In primary care, leaflets are often used to communicate health information. Increasingly, primary healthcare practitioners need to provide dietary advice. There is limited research exploring how nutrition information leaflets are used in primary care. The present study explored practitioner and lay experiences with respect to providing and receiving nutrition information in primary care, focusing in particular on the use of leaflets for nutrition information. A qualitative design was used incorporating focus groups with 57 practitioners based at seven general practitioner practices and a purposive sample of 30 lay participants attending six Consumer Health Organisations within one primary care trust. Focus groups were taped and transcribed verbatim and data were analysed thematically, assisted by computer software n6® (QSR International Pty Ltd, Melbourne, Australia). Practitioners discussed barriers to giving nutritional advice, access to leaflets, lay receptiveness to advice and their perceptions about the value of leaflets to lay people. Food was not considered in terms of its nutritional components by lay participants and the need for nutritional information was not perceived to be relevant until they had received a medical diagnosis. Lay participants discussed the importance of receiving nutritional advice relating to their medical diagnosis and the altered status of written information that was delivered personally. Practitioner and lay groups suggested improvements to ensure that nutritional advice be supported by relevant and appropriate written information. This research has underlined the continuing importance of nutrition information leaflets and concludes that there is particular value in involving lay participants in the development of nutrition information leaflets. © 2011 The Authors. Journal of Human Nutrition and Dietetics © 2011 The British Dietetic Association Ltd.
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Sukkari, Sana R; Al Humaidan, Abdullah S; Sasich, Larry D
2012-07-01
Inadequate access to useful scientifically accurate patient information is a major cause of the inappropriate use of drugs resulting in serious personal injury and related costs to the health care system. The definition of useful scientifically accurate patient information for prescription drugs was accepted by the US Secretary of the Department of Health and Human Services in 1996 as that derived from or consistent with the US FDA approved professional product label for a drug. Previous quality content studies found that English language patient drug information leaflets distributed by US pharmacies failed to meet minimum criteria defining useful and scientifically accurate information. Evaluation forms containing the explicit elements that define useful scientifically accurate information for three drugs with known serious adverse drug reactions were created based on the current US FDA approved professional product labels. The Arabic language patient drug information leaflets for celecoxib, paroxetine, and lamotrigine were obtained locally and evaluated using a methodology similar to that used in previous quality content patient drug information studies in the US. The Arabic leaflets failed to meet the definition of useful scientifically accurate information. The celecoxib leaflet contained 30% of the required information and the paroxetine and lamotrigine leaflets contained 24% and 20%, respectively. There are several limitations to this study. The Arabic leaflets from only one commercial North American vendor were evaluated and the evaluation included a limited number of drugs. A larger study is necessary to be able to generalize these results. The study results are consistent with those of previous quality content studies of commercially available English patient drug information leaflets. The results have important implications for patients as access to a reliable source of drug information may prevent harm or limit the suffering from serious adverse drug reactions.
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Occluder closing behavior: a key factor in mechanical heart valve cavitation.
Wu, Z J; Wang, Y; Hwang, N H
1994-04-01
A laser sweeping technique developed in this laboratory was found to be capable of monitoring the leaflet closing motion with microsecond precision. The leaflet closing velocity was measured inside the last three degrees before impact. Mechanical heart valve (MHV) leaflets were observed to close with a three-phase motion; the approaching phase, the decelerating phase, and the rebound phase, all of which take place within one to two milliseconds. The leaflet closing behavior depends mainly on the leaflet design and the hinge mechanism. Bileaflet and monoleaflet types of mechanical heart valves were tested in the mitral position in a physiologic mock circulatory flow loop, which incorporated a computer-controlled magnetic drive and an adjustable afterload system. The test loop was tuned to produce physiologic ventricular and aortic pressure wave forms at 70-120 beats/min, with the maximum ventricular dp/dt varying between 1500-5600 mmHg/sec. The experiments were conducted by controlling the cardiac output at a constant level between 2.0-9.0 liters/min. The measured time-displacement curve of each tested MHV leaflet and its geometry were taken as the input for computation of the squeeze flow field in the narrow gap space between the approaching leaflet and the valve housing. The results indicated rapid build-up of both the pressure and velocity in the gap field within microsecs before the impact. The pressure build-up in the gap space is apparently responsible for the leaflet deceleration before the impact. When the concurrent water hammer pressure reduction at closure was combined with the high energy squeeze jet ejected from the gap space, there were strong indications of the environment which favors micro cavitation inceptions in certain types of MHV.
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Atsumi, Satoru; Hara, Kunio; Arai, Yuji; Yamada, Manabu; Mizoshiri, Naoki; Kamitani, Aguri; Kubo, Toshikazu
2018-01-01
Abstract Rationale: Considering the risk of osteoarthritis following resection of a horizontally torn meniscus of the knee, repairing and preserving the meniscus as much as possible is preferred. We report 3 cases of restoration of horizontally torn menisci using a novel arthroscopic method we have called “all-inside interleaf vertical suture” that afforded preservation. Patient concerns: The 3 patients (aged 14, 17, and 21 years) had knee pain through sports activity. Diagnoses: All patients had horizontal tears in the posteromedial part of the meniscus. Interventions: The method uses Fast-Fix, whereby a first anchor is inserted from the tibial surface of the tear's superior leaflet and a second anchor is inserted from the femoral surface of the tear's inferior leaflet, and the 2 leaflets are closed using vertical suture. In all cases, the suture knots were embedded between the superior leaflet and inferior leaflet, avoiding contact with the articular cartilage, and superior leaflet and inferior leaflet crimping was good. Outcomes: All 3 were able to resume competing in sport and ≥ 1 year after surgery they had no pain and their postoperative mean Lysholm scores were 99.7. There were no complications or recurrence. On magnetic resonance imaging, the signal intensity of all the horizontal tears was high before surgery but low after surgery, suggesting that the repaired tear was healing. Lessons: The all-inside interleaf vertical suture procedure is a new surgical technique that can repair posteromedial horizontal meniscal tears of the knee of young people by easy crimping of the superior and inferior leaflets without the suture knots causing complications. PMID:29443758
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Bicuspid aortic valve hemodynamics: a fluid-structure interaction study
NASA Astrophysics Data System (ADS)
Chandra, Santanu; Seaman, Clara; Sucosky, Philippe
2011-11-01
The bicuspid aortic valve (BAV) is a congenital defect in which the aortic valve forms with two leaflets instead of three. While calcific aortic valve disease (CAVD) also develops in the normal tricuspid aortic valve (TAV), its progression in the BAV is more rapid. Although studies have suggested a mechano-potential root for the disease, the native BAV hemodynamics remains largely unknown. This study aimed at characterizing BAV hemodynamics and quantifying the degree of wall-shear stress (WSS) abnormality on BAV leaflets. Fluid-structure interaction models validated with particle-image velocimetry were designed to predict the flow and leaflet dynamics in idealized TAV and BAV anatomies. Valvular function was quantified in terms of the effective orifice area. The regional leaflet WSS was characterized in terms of oscillatory shear index, temporal shear magnitude and temporal shear gradient. The predictions indicate the intrinsic degree of stenosis of the BAV anatomy, reveal drastic differences in shear stress magnitude and pulsatility on BAV and TAV leaflets and confirm the side- and site-specificity of the leaflet WSS. Given the ability of abnormal fluid shear stress to trigger valvular inflammation, these results support the existence of a mechano-etiology of CAVD in the BAV.
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Arai, Motoharu; Maeda, Kazuto; Satoh, Hiroki; Miki, Akiko; Sawada, Yasufumi
2016-10-01
We created a draft of new patient information leaflets to ensure patients' proper use of drugs and to highlight safety issues and improvement plans extracted and proposed by small group discussions (SGD) with pharmacists. A total of 3 SGDs (participants: 15 pharmacists) were conducted with the aim of improving patient information leaflets for oral diabetes drugs. First, the disadvantages and advantages of the current instructions as well as requests for ideal patient information leaflets were obtained from participants. Conventional patient information leaflets that could be improved were useful to understand drug efficacy, adverse effects, and instructions for daily consumption of medicines, and to encourage patients to re-check drugs at home and inform their family of the measures to be taken in the case of adverse effects from the standpoint of patients. However, some disadvantages arose; for example, the instructions were difficult to read because of small lettering and illustrations and too much text. It was not tailored for individual patients, and descriptions about serious adverse effects caused patients much anxiety. Therefore, we have created a draft of new patient information leaflets with diabetes that are simpler and easier to understand and use concise wording and illustrations that are impactful.
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Oenocarpus bacaba and Oenocarpus bataua Leaflets and Roots: A New Source of Antioxidant Compounds
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
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Pouch, Alison M; Wang, Hongzhi; Takabe, Manabu; Jackson, Benjamin M; Sehgal, Chandra M; Gorman, Joseph H; Gorman, Robert C; Yushkevich, Paul A
2013-01-01
The aortic valve has been described with variable anatomical definitions, and the consistency of 2D manual measurement of valve dimensions in medical image data has been questionable. Given the importance of image-based morphological assessment in the diagnosis and surgical treatment of aortic valve disease, there is considerable need to develop a standardized framework for 3D valve segmentation and shape representation. Towards this goal, this work integrates template-based medial modeling and multi-atlas label fusion techniques to automatically delineate and quantitatively describe aortic leaflet geometry in 3D echocardiographic (3DE) images, a challenging task that has been explored only to a limited extent. The method makes use of expert knowledge of aortic leaflet image appearance, generates segmentations with consistent topology, and establishes a shape-based coordinate system on the aortic leaflets that enables standardized automated measurements. In this study, the algorithm is evaluated on 11 3DE images of normal human aortic leaflets acquired at mid systole. The clinical relevance of the method is its ability to capture leaflet geometry in 3DE image data with minimal user interaction while producing consistent measurements of 3D aortic leaflet geometry.
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Retrieval of a leaflet escaped in a Tri-technologies bileaflet mechanical prosthetic valve.
Cianciulli, Tomás F; Lax, Jorge A; Saccheri, María C; Guidoin, Robert; Salvado, César M; Fernández, Adrián J; Prezioso, Horacio A
2008-01-01
The escape of the prosthetic heart valve disc is one of the causes of prosthetic dysfunction that requires emergency surgery. The removal of the embolized disc should be carried out because of the risk of a progressive extrusion on the aortic wall. Several imaging techniques can be used for the detection of the missing disc localization. In this report we describe a 32-year-old man who underwent mitral valve replacement with a Tri-technologies bileaflet valve three years ago, and was admitted in cardiogenic shock. Transesophageal echocardiography showed acute-onset massive mitral regurgitation. The patient underwent emergency replacement of the prosthetic valve. Only one of the two leaflets remained in the removed prosthetic valve. The missing leaflet could not be found within the cardiac cavity. The abdominal fluoroscopic study and plain radiography were unable to detect the escaped leaflet. The abdominal computed tomography scan and the ultrasound showed the escaped leaflet in the terminal portion of the aortic bifurcation. To retrieve the embolized disc laparotomy and aortotomy were performed three months later. The escaped leaflet shows a fracture of one of the pivot systems caused by structural failure. This kind of failure mode is usually the result of high stress concentration.
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Staba, Richard J; Ard, Tyler D; Benison, Alexander M; Barth, Daniel S
2005-05-01
Whisker evoked fast oscillations (FOs; >200 Hz) within the rodent posteromedial barrel subfield are thought to reflect very rapid integration of multiwhisker stimuli, yet the pathways mediating FO interactions remain unclear and may involve interactions within thalamus and/or cortex. In the present study using anesthetized rats, a cortical incision was made between sites representing the stimulated whiskers to determine how intracortical networks contributed to patterns of FOs. With cortex intact, simultaneous stimulation of a pair of whiskers aligned in a row evoked supralinear responses between sites separated by several millimeters. In contrast, stimulation of a nonadjacent pair of whiskers within an arc evoked FOs with no evidence for nonlinear interactions. However, stimulation of an adjacent pair of whiskers in an arc did evoke supralinear responses. After a cortical cut, supralinear interactions associated with FOs within a row were lost. These data indicate a distinct bias for stronger long-range connectivity that extends along barrel rows and that horizontal intracortical pathways exclusively mediate FO-related integration of tactile information.
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Hamm, Jordan P; Ethridge, Lauren E; Boutros, Nashaat N; Keshavan, Matcheri S; Sweeney, John A; Pearlson, Godfrey D; Tamminga, Carol A; Clementz, Brett A
2014-04-01
Disrupted sensory processing is a core feature of psychotic disorders. Auditory paired stimuli (PS) evoke a complex neural response, but it is uncertain which aspects reflect shared and/or distinct liability for the most common severe psychoses, schizophrenia (SZ) and psychotic bipolar disorder (BDP). Evoked time-voltage/time-frequency domain responses quantified with EEG during a typical PS paradigm (S1-S2) were compared among proband groups (SZ [n = 232], BDP [181]), their relatives (SZrel [259], BDPrel [220]), and healthy participants (H [228]). Early S1-evoked responses were reduced in SZ and BDP, while later/S2 abnormalities showed SZ/SZrel and BDP/BDPrel specificity. Relatives' effects were absent/small despite significant familiality of the entire auditorineural response. This pattern suggests general and divergent biological pathways associated with psychosis, yet may reflect complications with conditioning solely on clinical phenomenology. Copyright © 2014 Society for Psychophysiological Research.
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Structural basis for maintenance of bacterial outer membrane lipid asymmetry.
Abellón-Ruiz, Javier; Kaptan, Shreyas S; Baslé, Arnaud; Claudi, Beatrice; Bumann, Dirk; Kleinekathöfer, Ulrich; van den Berg, Bert
2017-12-01
The Gram-negative bacterial outer membrane (OM) is a unique bilayer that forms an efficient permeation barrier to protect the cell from noxious compounds 1 , 2 . The defining characteristic of the OM is lipid asymmetry, with phospholipids comprising the inner leaflet and lipopolysaccharides comprising the outer leaflet 1-3 . This asymmetry is maintained by the Mla pathway, a six-component system that is widespread in Gram-negative bacteria and is thought to mediate retrograde transport of misplaced phospholipids from the outer leaflet of the OM to the cytoplasmic membrane 4 . The OM lipoprotein MlaA performs the first step in this process via an unknown mechanism that does not require external energy input. Here we show, using X-ray crystallography, molecular dynamics simulations and in vitro and in vivo functional assays, that MlaA is a monomeric α-helical OM protein that functions as a phospholipid translocation channel, forming a ~20-Å-thick doughnut embedded in the inner leaflet of the OM with a central, amphipathic pore. This architecture prevents access of inner leaflet phospholipids to the pore, but allows outer leaflet phospholipids to bind to a pronounced ridge surrounding the channel, followed by diffusion towards the periplasmic space. Enterobacterial MlaA proteins form stable complexes with OmpF/C 5,6 , but the porins do not appear to play an active role in phospholipid transport. MlaA represents a lipid transport protein that selectively removes outer leaflet phospholipids to help maintain the essential barrier function of the bacterial OM.
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Hellier, E; Edworthy, J; Newbold, L; Titchener, K; Tucker, M; Gabe-Thomas, E
2014-09-01
Guidelines for the design of emergency communications were derived from primary research and interrogation of the literature. The guidelines were used to re-design a nuclear emergency preparedness leaflet routinely distributed to households in the local area. Pre-test measures of memory for, and self-reported understanding of, nuclear safety information were collected. The findings revealed high levels of non-receipt of the leaflet, and among those who did receive it, memory for safety advice was poor. Subjective evaluations of the trial leaflet suggested that it was preferred and judged easier to understand than the original. Objective measures of memory for the two leaflets were also recorded, once after the study period, and again one week or four weeks later. Memory for the advice was better, at all time periods, when participants studied the trial leaflet. The findings showcase evaluation of emergency preparedness literature and suggest that extant research findings can be applied to the design of communications to improve memory and understandability. Studies are described that showcase the use of research-based guidelines to design emergency communications and provide both subjective and objective data to support designing emergency communications in this way. In addition, the research evaluates the effectiveness of emergency preparedness leaflets that are routinely distributed to households. This work is of relevance to academics interested in risk communication and to practitioners involved in civil protection and emergency preparedness. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.
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Isolated effect of geometry on mitral valve function for in silico model development.
Siefert, Andrew William; Rabbah, Jean-Pierre Michel; Saikrishnan, Neelakantan; Kunzelman, Karyn Susanne; Yoganathan, Ajit Prithivaraj
2015-01-01
Computational models for the heart's mitral valve (MV) exhibit several uncertainties that may be reduced by further developing these models using ground-truth data-sets. This study generated a ground-truth data-set by quantifying the effects of isolated mitral annular flattening, symmetric annular dilatation, symmetric papillary muscle (PM) displacement and asymmetric PM displacement on leaflet coaptation, mitral regurgitation (MR) and anterior leaflet strain. MVs were mounted in an in vitro left heart simulator and tested under pulsatile haemodynamics. Mitral leaflet coaptation length, coaptation depth, tenting area, MR volume, MR jet direction and anterior leaflet strain in the radial and circumferential directions were successfully quantified at increasing levels of geometric distortion. From these data, increase in the levels of isolated PM displacement resulted in the greatest mean change in coaptation depth (70% increase), tenting area (150% increase) and radial leaflet strain (37% increase) while annular dilatation resulted in the largest mean change in coaptation length (50% decrease) and regurgitation volume (134% increase). Regurgitant jets were centrally located for symmetric annular dilatation and symmetric PM displacement. Asymmetric PM displacement resulted in asymmetrically directed jets. Peak changes in anterior leaflet strain in the circumferential direction were smaller and exhibited non-significant differences across the tested conditions. When used together, this ground-truth data-set may be used to parametrically evaluate and develop modelling assumptions for both the MV leaflets and subvalvular apparatus. This novel data may improve MV computational models and provide a platform for the development of future surgical planning tools.
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Rinia, H A; Demel, R A; van der Eerden, J P; de Kruijff, B
1999-01-01
Asymmetric bilayers of different phospholipid compositions have been prepared by the Langmuir-Blodgett (L-B) method, and imaged by atomic force microscopy (AFM). Such bilayers can function as a model for biological membranes. The first leaflet consisted of zwitterionic phospholipids phosphatidylcholine (PC) or phosphatidylethanolamine (PE). The second leaflet consisted of the anionic phospholipid phosphatidylglycerol (PG), in either the condensed or liquid phase or, for comparison, of PC. Different bilayers showed different morphology. In all bilayers defects in the form of holes were present. In some bilayers with a first leaflet consisting of PC, polygonal line-shaped defects were observed, whereas when the first leaflet consisted of PE, mainly round defects were seen. Not only the shape, but also the amount of defects varied, depending on the condition and the composition of the second leaflet. In most of the PG-containing systems the defects were surrounded by elevations, which reversibly disappeared in the presence of divalent cations. This is the first time that such elevations have been observed on phospholipid bilayers. We propose that they are induced by phospholipid exchange between the two leaflets around the defects, leading to the presence of negatively charged phospholipids in the first leaflet. Because the substrate is also negatively charged, the bilayer around the edges is repelled and lifted up. Since it was found that the elevations are indeed detached from the substrate, we refer to this effect as bilayer blistering. PMID:10465778
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Systolic Anterior Motion of the Mitral Valve after Mitral Valve Repair
Sternik, Leonid; Zehr, Kenton J.
2005-01-01
Factors predisposing patients to systolic anterior motion of the mitral valve (SAM) with left ventricular outflow tract (LVOT) obstruction after mitral valve repair are the presence of a myxomatous mitral valve with redundant leaflets, a nondilated hyperdynamic left ventricle, and a short distance between the mitral valve coaptation point and the ventricular septum after repair. From December 1999 through March 2000, we used our surgical method in 6 patients with severely myxomatous regurgitant mitral valves who were at risk of developing SAM. Leaflets were markedly redundant in all 6. Left ventricular function was hyperdynamic in 4 patients and normal in 2. Triangular or quadrangular resection of the midportion of the posterior leaflet and posterior band annuloplasty were performed. To prevent SAM and LVOT obstruction, extra, posteriorly directed, mid-posterior-leaflet secondary chordae tendineae, which would otherwise have been resected, were transferred to the underside of the middle of the mid-anterior leaflet with a small piece of associated valve as an anchoring pledget. This kept the redundant anterior leaflet edge, which extended below the coaptation point, away from the LVOT. No post-repair SAM or LVOT obstruction was observed on intraoperative or discharge echocardiography. All patients had no or trivial residual mitral regurgitation. We conclude that extra chordae tendineae, when available, can be used in mitral valve repair to tether the redundant anterior leaflet and thus prevent it from flipping into the LVOT. This will theoretically prevent SAM and LVOT obstruction in patients with risk factors for SAM. PMID:15902821
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Outlet strut fracture and leaflet escape of Bjork-Shiley convexo-concave valve.
Uchino, Gaku; Yoshida, Hideo; Sakoda, Naoya; Hattori, Shigeru; Kawabata, Takuya; Saiki, Munehiro; Fujita, Yasufumi; Yunoki, Keiji; Hisamochi, Kunikazu; Mine, Yoshinari
2017-06-01
Prosthetic valve fracture is a serious complication and may arise in patient post-valve replacement. We experienced an outlet strut fracture and leaflet escape of a Bjork-Shiley convexo-concave valve. We performed an emergency redo mitral valve replacement and successfully retrieved the fractured strut and escaped leaflet from superficial femoral artery and the abdominal aorta. The patient showed an uneventful postoperative recovery.
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Scott, Sophie; Lavan, Nadine; Chen, Sinead; McGettigan, Carolyn
2014-01-01
Laughter is often considered to be the product of humour. However laughter is a social emotion, occurring most often in interactions, where it is associated with bonding, agreement, affection and emotional regulation. Laughter is underpinned by complex neural systems, allowing it to be used flexibly: in humans and chimpanzees, social (voluntary) laughter is distinctly different from evoked (involuntary) laughter, a distinction which is also seen in brain imaging studies of laughter. PMID:25439499
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Cheng, Sara Y; Chou, George; Buie, Creighton; Vaughn, Mark W; Compton, Campbell; Cheng, Kwan H
2016-03-01
We used molecular dynamics simulations to explore the effects of asymmetric transbilayer distribution of anionic phosphatidylserine (PS) lipids on the structure of a protein on the membrane surface and subsequent protein-lipid interactions. Our simulation systems consisted of an amyloidogenic, beta-sheet rich dimeric protein (D42) absorbed to the phosphatidylcholine (PC) leaflet, or protein-contact PC leaflet, of two membrane systems: a single-component PC bilayer and double PC/PS bilayers. The latter comprised of a stable but asymmetric transbilayer distribution of PS in the presence of counterions, with a 1-component PC leaflet coupled to a 1-component PS leaflet in each bilayer. The maximally asymmetric PC/PS bilayer had a non-zero transmembrane potential (TMP) difference and higher lipid order packing, whereas the symmetric PC bilayer had a zero TMP difference and lower lipid order packing under physiologically relevant conditions. Analysis of the adsorbed protein structures revealed weaker protein binding, more folding in the N-terminal domain, more aggregation of the N- and C-terminal domains and larger tilt angle of D42 on the PC leaflet surface of the PC/PS bilayer versus the PC bilayer. Also, analysis of protein-induced membrane structural disruption revealed more localized bilayer thinning in the PC/PS versus PC bilayer. Although the electric field profile in the non-protein-contact PS leaflet of the PC/PS bilayer differed significantly from that in the non-protein-contact PC leaflet of the PC bilayer, no significant difference in the electric field profile in the protein-contact PC leaflet of either bilayer was evident. We speculate that lipid packing has a larger effect on the surface adsorbed protein structure than the electric field for a maximally asymmetric PC/PS bilayer. Our results support the mechanism that the higher lipid packing in a lipid leaflet promotes stronger protein-protein but weaker protein-lipid interactions for a dimeric protein on membrane surfaces. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
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Computational fluid dynamics simulation of transcatheter aortic valve degeneration.
Dwyer, Harry A; Matthews, Peter B; Azadani, Ali; Jaussaud, Nicolas; Ge, Liang; Guy, T Sloane; Tseng, Elaine E
2009-08-01
Studied under clinical trials, transcatheter aortic valves (TAV) have demonstrated good short-term feasibility and results in high-risk surgical patients with severe aortic stenosis. However, their long-term safety and durability are unknown. The objective of this study is to evaluate hemodynamic changes within TAV created by bioprosthetic leaflet degeneration. Computational fluid dynamics (CFD) simulations were performed to evaluate the hemodynamics through TAV sclerosis (35% orifice reduction) and stenosis (78% orifice reduction). A three-dimensional surface mesh of the TAV within the aortic root was generated for each simulation. Leaflets were contained within an open, cylindrical body without attachment to the sinus commissures representing the stent. A continuous surface between the annulus and TAV excluded the geometry of the native calcified leaflets and prevented paravalvular leak. Unsteady control volume analysis throughout systole was used to calculate leaflet shear stress and total force on the TAV. Sclerosis increased total force on the TAV by 63% (0.602-0.98 N). Advancement of degeneration from sclerosis to stenosis was accompanied by an 86% increase in total force (1.82 N) but only a 32% increase in peak wall shear stress on the leaflets. Of the total force exerted on the TAV, 99% was in the direction of axial flow. Shear stresses on the TAV were greatest during peak systolic flow with stress concentrations on the tips of the leaflets. In the normal TAV, the aortic root geometry and physiologic flow dominate location and magnitude of shear stress. Following leaflet degeneration, the specific geometry of the stenosis dictates the profile of axial velocity leaving the TAV and shear stress on the leaflets. A dramatic increase in peak leaflet shear stress was observed (115 Pa stenosis vs. 87 Pa sclerosis and 29 Pa normal). CFD simulations in this study provide the first of its kind data quantifying hemodynamics within stenosed TAV. Stenosis leads to significant forces of TAV during systole; however, diastolic forces predominate even with significant stenosis. Substantial changes in peak shear stress occur with TAV degeneration. As the first implanted TAV begin to stenose, the authors recommend watchful examination for device failure.
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Afuwape, Olusoji A. T.; Wasser, Catherine R.; Schikorski, Thomas
2016-01-01
Key points Synaptic transmission is mediated by the release of neurotransmitters from synaptic vesicles in response to stimulation or through the spontaneous fusion of a synaptic vesicle with the presynaptic plasma membrane.There is growing evidence that synaptic vesicles undergoing spontaneous fusion versus those fusing in response to stimuli are functionally distinct.In this study, we acutely probe the effects of intravesicular free radical generation on synaptic vesicles that fuse spontaneously or in response to stimuli.By targeting vesicles that preferentially release spontaneously, we can dissociate the effects of intravesicular free radical generation on spontaneous neurotransmission from evoked neurotransmission and vice versa.Taken together, these results further advance our knowledge of the synapse and the nature of the different synaptic vesicle pools mediating neurotransmission. Abstract Earlier studies suggest that spontaneous and evoked neurotransmitter release processes are maintained by synaptic vesicles which are segregated into functionally distinct pools. However, direct interrogation of the link between this putative synaptic vesicle pool heterogeneity and neurotransmission has been difficult. To examine this link, we tagged vesicles with horseradish peroxidase (HRP) – a haem‐containing plant enzyme – or antibodies against synaptotagmin‐1 (syt1). Filling recycling vesicles in hippocampal neurons with HRP and subsequent treatment with hydrogen peroxide (H2O2) modified the properties of neurotransmitter release depending on the route of HRP uptake. While strong depolarization‐induced uptake of HRP suppressed evoked release and augmented spontaneous release, HRP uptake during mild activity selectively impaired evoked release, whereas HRP uptake at rest solely potentiated spontaneous release. Expression of a luminal HRP‐tagged syt1 construct and subsequent H2O2 application resulted in a similar increase in spontaneous release and suppression as well as desynchronization of evoked release, recapitulating the canonical syt1 loss‐of‐function phenotype. An antibody targeting the luminal domain of syt1, on the other hand, showed that augmentation of spontaneous release and suppression of evoked release phenotypes are dissociable depending on whether the antibody uptake occurred at rest or during depolarization. Taken together, these findings indicate that vesicles that maintain spontaneous and evoked neurotransmitter release preserve their identity during recycling and syt1 function in suppression of spontaneous neurotransmission can be acutely dissociated from syt1 function to synchronize synaptic vesicle exocytosis upon stimulation. PMID:27723113
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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
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Canning, Brendan J; Mazzone, Stuart B; Meeker, Sonya N; Mori, Nanako; Reynolds, Sandra M; Undem, Bradley J
2004-01-01
We have identified the tracheal and laryngeal afferent nerves regulating cough in anaesthetized guinea-pigs. Cough was evoked by electrical or mechanical stimulation of the tracheal or laryngeal mucosa, or by citric acid applied topically to the trachea or larynx. By contrast, neither capsaicin nor bradykinin challenges to the trachea or larynx evoked cough. Bradykinin and histamine administered intravenously also failed to evoke cough. Electrophysiological studies revealed that the majority of capsaicin-sensitive afferent neurones (both Aδ- and C-fibres) innervating the rostral trachea and larynx have their cell bodies in the jugular ganglia and project to the airways via the superior laryngeal nerves. Capsaicin-insensitive afferent neurones with cell bodies in the nodose ganglia projected to the rostral trachea and larynx via the recurrent laryngeal nerves. Severing the recurrent nerves abolished coughing evoked from the trachea and larynx whereas severing the superior laryngeal nerves was without effect on coughing. The data indicate that the tracheal and laryngeal afferent neurones regulating cough are polymodal Aδ-fibres that arise from the nodose ganglia. These afferent neurones are activated by punctate mechanical stimulation and acid but are unresponsive to capsaicin, bradykinin, smooth muscle contraction, longitudinal or transverse stretching of the airways, or distension. Comparing these physiological properties with those of intrapulmonary mechanoreceptors indicates that the afferent neurones mediating cough are quite distinct from the well-defined rapidly and slowly adapting stretch receptors innervating the airways and lungs. We propose that these airway afferent neurones represent a distinct subtype and that their primary function is regulation of the cough reflex. PMID:15004208
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Short-Term Memory in Habituation and Dishabituation
ERIC Educational Resources Information Center
Whitlow, Jesse William, Jr.
1975-01-01
The present research evaluated the refractorylike response decrement, as found in habituation of auditory evoked peripheral vasoconstriction in rabbits, to determine whether or not it represents a short-term habituation process distinct from effector fatigue or sensory adaptation. (Editor)
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Mechanism of valvular regurgitation.
Khoo, Nee S; Smallhorn, Jeffery F
2011-10-01
Despite improvements in surgical techniques, valvular regurgitation results in major morbidity in children with heart disease. Functional anatomy, mechanisms of valve closure and adaptation to changing hemodynamic stress in normal mitral and tricuspid valves are complex and only partially understood. As well, pathology of atrioventricular valve regurgitation is further complicated by congenital valve abnormalities involving leaflet tissue, supporting chordal apparatus and displaced papillary muscles. This review provides a current understanding of the mechanisms that result in atrioventricular valve failure. Mitral valve leaflets have contractile elements, in addition to atrial muscle modulation of leaflet tension. When placed under mechanical tethering stress, the mitral valve adapts by leaflet expansion, which increases coaptation surface reserve and chordal thickening. Both pediatric and adult studies are increasingly reporting on the importance of subvalvar apparatus function in maintaining valve competency. The maintenance of efficient valve function is accomplished by a complex series of events involving atrial and annular contraction, annular deformation, active leaflet tension, chordal transmission of papillary muscle contractions and ventricular contraction.
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Tarca, Adrian J; Eckersley, Luke; Kothari, Darshan
2017-10-01
This brief report describes a case of flail anterior tricuspid valve leaflet in a neonate associated with maternal antiphospholipid syndrome. Fetal echocardiography at 27 weeks of gestation showed competent atrioventricular valves with biventricular echogenic chordae. Fetal distress was noted at delivery, and echocardiography showed a flail anterior leaflet of the tricuspid valve with severe regurgitation. Possible causation and implications of maternal antiphospholipid syndrome are discussed.
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Effect of a leaflet given to parents on knowledge of tooth avulsion.
Ghaderi, F; Adl, A; Ranjbar, Z
2013-03-01
Parents can play an important role in improving the prognosis of avulsed permanent teeth if they are properly informed about the necessary dental first-aid steps at the time of an accident. The purpose of this study was to assess the knowledge of Shirazi parents in traumatic a simple leaflet on improving their knowledge about this topic. One hundred and fifty parents of children receiving dental care at the Shiraz Dental School participated in this study. Half of the participants received an informative leaflet with the possibility of asking questions about it to an operator, while the other half did not receive any leaflets and served as a control group. Using a questionnaire and a scoring system, the level of knowledge of parents was measured in the following categories: general knowledge of tooth avulsion, knowledge of replantation and primary/permanent teeth, knowledge of how to clean an avulsed tooth, knowledge of extra- oral time, and knowledge of storage, methods and transporting media. The results showed that knowledge level was low among Shirazi parents. Improvements were observed in all the categories of knowledge as a result of reading the leaflet and answering the questions. A simple leaflet is a suitable tool to impart knowledge to parents and improve awareness about tooth avulsion.
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Martin, Caitlin; Sun, Wei
2015-01-01
Transcatheter aortic valve (TAV) intervention is now the standard-of-care treatment for inoperable patients and a viable alternative treatment option for high-risk patients with symptomatic aortic stenosis. While the procedure is associated with lower operative risk and shorter recovery times than traditional surgical aortic valve (SAV) replacement, TAV intervention is still not considered for lower-risk patients due in part to concerns about device durability. It is well known that bioprosthetic SAVs have limited durability, and TAVs are generally assumed to have even worse durability, yet there is little long-term data to confirm this suspicion. In this study, TAV and SAV leaflet fatigue due to cyclic loading was investigated through finite element analysis by implementing a computational soft tissue fatigue damage model to describe the behavior of the pericardial leaflets. Under identical loading conditions and with identical leaflet tissue properties, the TAV leaflets sustained higher stresses, strains, and fatigue damage compared to the SAV leaflets. The simulation results suggest that the durability of TAVs may be significantly reduced compared to SAVs to about 7.8 years. The developed computational framework may be useful in optimizing TAV design parameters to improve leaflet durability, and assessing the effects of underexpanded, elliptical, or non-uniformly expanded stent deployment on TAV durability. PMID:26294354
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De Paulis, R; De Matteis, G M; Nardi, P; Scaffa, R; Buratta, M M; Chiariello, L
2001-08-01
The durability of aortic valve-sparing procedures is negatively affected by increased leaflet stress in the absence of normally shaped sinuses of Valsalva. We compared valve motion after remodeling procedures using a standard conduit and a specifically designed aortic root conduit. Echocardiographic studies of the aortic valve dynamics were performed in 14 patients after remodeling of the aortic root (7 standard conduits, group A; 7 new conduits, group B) and in 7 controls (group C). Opening and closing leaflet velocities and percent of slow closing leaflet displacement were measured. Root distensibility and the pressure strain of the elastic modulus were measured at all root levels. Root distensibility and the pressure strain of the elastic modulus were different in group A and B only at the sinuses (p < 0.001). Opening and closing leaflet velocities were not different among groups. Slow closing leaflet displacement was markedly more evident in group B patients (24.2%+/-1.9% versus 2.5%+/-1.9% in group A, p < 0.001) and similar to controls (22.1%+/-7.9%). The new conduit guarantees dynamic features of the aortic valve leaflets superior to those obtained with standard conduits and more similar to normal subjects.
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Damianos, Konstantina; Ferrando, Riccardo
2012-02-21
The structural modifications of small supported gold clusters caused by realistic surface defects (steps) in the MgO(001) support are investigated by computational methods. The most stable gold cluster structures on a stepped MgO(001) surface are searched for in the size range up to 24 Au atoms, and locally optimized by density-functional calculations. Several structural motifs are found within energy differences of 1 eV: inclined leaflets, arched leaflets, pyramidal hollow cages and compact structures. We show that the interaction with the step clearly modifies the structures with respect to adsorption on the flat defect-free surface. We find that leaflet structures clearly dominate for smaller sizes. These leaflets are either inclined and quasi-horizontal, or arched, at variance with the case of the flat surface in which vertical leaflets prevail. With increasing cluster size pyramidal hollow cages begin to compete against leaflet structures. Cage structures become more and more favourable as size increases. The only exception is size 20, at which the tetrahedron is found as the most stable isomer. This tetrahedron is however quite distorted. The comparison of two different exchange-correlation functionals (Perdew-Burke-Ernzerhof and local density approximation) show the same qualitative trends. This journal is © The Royal Society of Chemistry 2012
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Morphologic-echocardiographic correlates of Ebstein's malformation.
Rusconi, P G; Zuberbuhler, J R; Anderson, R H; Rigby, M L
1991-07-01
The cross-sectional echocardiographic findings were analysed retrospectively in 26 patients with Ebstein's malformation in the light of studies of autopsied specimens from different patients showing this lesion. The salient anatomical feature in diagnosis is the finding of the hinge point of the septal and mural leaflets of the valve within the inlet component of the right ventricle rather than at the atrioventricular junction. The other important feature is the nature of the distal attachment of the leaflets, particularly the anterosuperior one, which can either be in focal or linear fashion. The hinge point of the septal leaflet was noted echocardiographically to be displaced in 19 patients but, significantly, the leaflet was absent in the other seven. Also significant was that the hinge point of the mural leaflet at the crux had been visualized in only 15 of the patients. The anterosuperior leaflet had a distal linear attachment in 20 of the patients, with the anteroseptal commissure becoming a keyhole in six of these through which blood passed to the functional right ventricle. The valve remained a competent structure, even though closing at the junction of atrialized and functional components of the right ventricle rather than at the atrioventricular junction. Cross-sectional echocardiography is the technique of choice with which to display the salient morphological features of Ebstein's malformation.
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Mathew, Elizabeth M; Rajiah, Kingston; Sharma, Krishana Kumar
2013-12-01
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. 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). 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. 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.
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INTERLAYER MICROMECHANICS OF THE AORTIC HEART VALVE LEAFLET
Buchanan, Rachel M.; Sacks, Michael S.
2014-01-01
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, 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. PMID:24292631
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Greco, Nancy M; Sánchez, Norma E; Liljesthröm, Gerardo G
2005-01-01
Neoseiulus californicus (McGregor) is a promising agent for successful Tetranychus urticae Koch control through conservation techniques, in strawberry crops in La Plata (Buenos Aires, Argentina). In prey-predator interaction, initial relative densities have an important effect on system dynamics. The economic threshold level (ETL) used for this pest in the present study was 50 active mites per leaflet. In our laboratory experiments, initial T. urticae to N. californicus ratio had a significant effect on the population abundance of T. urticae at a 7-day period. When pest/predator ratio was 5/1 (at initial pest densities from 5 to 15 females/leaflet) the final number of active T. urticae/leaflet was significantly lower than the ETL, while at 20 females/leaflet this number did not differ from the ETL. At 7.5/1 ratio, the final number of active T. urticae/leaflet, at initial pest densities from 5 to 15 females/leaflet, reached the ETL without surpassing it. At 10/1 and 15/1 ratios, pest densities exceeded the ETL only at 15 initial T. urticae/leaflet. Most greenhouse and field observations were consistent with the predictions of a graphical model based on experimental results. This predator was very effective in limiting pest densities at a 7-day period and within the range of pest-predator ratios and absolute densities used in this study. Conservation of N. californicus promoting favorable pest/predator ratios may result in early control of T. urticae.
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Manipulation of valve composition to elucidate the role of collagen in aortic valve calcification
2014-01-01
Background Extracellular matrix (ECM) disarray is found in calcific aortic valvular disease (CAVD), yet much remains to be learned about the role of individual ECM components in valvular interstitial cell (VIC) function and dysfunction. Previous clinical analyses have shown that calcification is associated with decreased collagen content, while previous in vitro work has suggested that the presence of collagen attenuates the responsiveness of VICs to pro-calcific stimuli. The current study uses whole leaflet cultures to examine the contributions of endogenous collagen in regulating the phenotype and calcification of VICs. Methods A “top-down” approach was used to characterize changes in VIC phenotype in response to collagen alterations in the native 3D environment. Collagen-deficient leaflets were created via enzymatic treatment and cultured statically for six days in vitro. After culture, leaflets were harvested for analysis of DNA, proliferation, apoptosis, ECM composition, calcification, and gene/protein expression. Results In general, disruption of collagen was associated with increased expression of disease markers by VICs in whole organ leaflet culture. Compared to intact control leaflets, collagen-deficient leaflets demonstrated increased VIC proliferation and apoptosis, increased expression of disease-related markers such as alpha-smooth muscle actin, alkaline phosphatase, and osteocalcin, and an increase in calcification as evidenced by positive von Kossa staining. Conclusions These results indicate that disruption of the endogenous collagen structure in aortic valves is sufficient to stimulate pathological consequences in valve leaflet cultures, thereby highlighting the importance of collagen and the valve extracellular matrix in general in maintaining homeostasis of the valve phenotype. PMID:24581344
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Murphy, I G; Collins, J; Powell, A; Markl, M; McCarthy, P; Malaisrie, S C; Carr, J C; Barker, A J
2017-08-01
Bicuspid aortic valve (BAV) disease is heterogeneous and related to valve dysfunction and aortopathy. Appropriate follow up and surveillance of patients with BAV may depend on correct phenotypic categorization. There are multiple classification schemes, however a need exists to comprehensively capture commissure fusion, leaflet asymmetry, and valve orifice orientation. Our aim was to develop a BAV classification scheme for use at MRI to ascertain the frequency of different phenotypes and the consistency of BAV classification. The BAV classification scheme builds on the Sievers surgical BAV classification, adding valve orifice orientation, partial leaflet fusion and leaflet asymmetry. A single observer successfully applied this classification to 386 of 398 Cardiac MRI studies. Repeatability of categorization was ascertained with intraobserver and interobserver kappa scores. Sensitivity and specificity of MRI findings was determined from operative reports, where available. Fusion of the right and left leaflets accounted for over half of all cases. Partial leaflet fusion was seen in 46% of patients. Good interobserver agreement was seen for orientation of the valve opening (κ = 0.90), type (κ = 0.72) and presence of partial fusion (κ = 0.83, p < 0.0001). Retrospective review of operative notes showed sensitivity and specificity for orientation (90, 93%) and for Sievers type (73, 87%). The proposed BAV classification schema was assessed by MRI for its reliability to classify valve morphology in addition to illustrating the wide heterogeneity of leaflet size, orifice orientation, and commissural fusion. The classification may be helpful in further understanding the relationship between valve morphology, flow derangement and aortopathy.
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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.
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Isolated Effect of Geometry on Mitral Valve Function for In-Silico Model Development
Siefert, Andrew William; Rabbah, Jean-Pierre Michel; Saikrishnan, Neelakantan; Kunzelman, Karyn Susanne; Yoganathan, Ajit Prithivaraj
2013-01-01
Computational models for the heart’s mitral valve (MV) exhibit several uncertainties which may be reduced by further developing these models using ground-truth data sets. The present study generated a ground-truth data set by quantifying the effects of isolated mitral annular flattening, symmetric annular dilatation, symmetric papillary muscle displacement, and asymmetric papillary muscle displacement on leaflet coaptation, mitral regurgitation (MR), and anterior leaflet strain. MVs were mounted in an in vitro left heart simulator and tested under pulsatile hemodynamics. Mitral leaflet coaptation length, coaptation depth, tenting area, MR volume, MR jet direction, and anterior leaflet strain in the radial and circumferential directions were successfully quantified for increasing levels of geometric distortion. From these data, increasing levels of isolated papillary muscle displacement resulted in the greatest mean change in coaptation depth (70% increase), tenting area (150% increase), and radial leaflet strain (37% increase) while annular dilatation resulted in the largest mean change in coaptation length (50% decrease) and regurgitation volume (134% increase). Regurgitant jets were centrally located for symmetric annular dilatation and symmetric papillary muscle displacement. Asymmetric papillary muscle displacement resulted in asymmetrically directed jets. Peak changes in anterior leaflet strain in the circumferential direction were smaller and exhibited non-significant differences across the tested conditions. When used together, this ground-truth data may be used to parametrically evaluate and develop modeling assumptions for both the MV leaflets and subvalvular apparatus. This novel data may improve MV computational models and provide a platform for the development of future surgical planning tools. PMID:24059354
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Mao, Wenbin; Li, Kewei; Sun, Wei
2016-01-01
Computational modeling of heart valve dynamics incorporating both fluid dynamics and valve structural responses has been challenging. In this study, we developed a novel fully-coupled fluid-structure interaction (FSI) model using smoothed particle hydrodynamics (SPH). A previously developed nonlinear finite element (FE) model of transcatheter aortic valves (TAV) was utilized to couple with SPH to simulate valve leaflet dynamics throughout the entire cardiac cycle. Comparative simulations were performed to investigate the impact of using FE-only models versus FSI models, as well as an isotropic versus an anisotropic leaflet material model in TAV simulations. From the results, substantial differences in leaflet kinematics between FE-only and FSI models were observed, and the FSI model could capture the realistic leaflet dynamic deformation due to its more accurate spatial and temporal loading conditions imposed on the leaflets. The stress and the strain distributions were similar between the FE and FSI simulations. However, the peak stresses were different due to the water hammer effect induced by the flow inertia in the FSI model during the closing phase, which led to 13%–28% lower peak stresses in the FE-only model compared to that of the FSI model. The simulation results also indicated that tissue anisotropy had a minor impact on hemodynamics of the valve. However, a lower tissue stiffness in the radial direction of the leaflets could reduce the leaflet peak stress caused by the water hammer effect. It is hoped that the developed FSI models can serve as an effective tool to better assess valve dynamics and optimize next generation TAV designs. PMID:27844463
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Mao, Wenbin; Li, Kewei; Sun, Wei
2016-12-01
Computational modeling of heart valve dynamics incorporating both fluid dynamics and valve structural responses has been challenging. In this study, we developed a novel fully-coupled fluid-structure interaction (FSI) model using smoothed particle hydrodynamics (SPH). A previously developed nonlinear finite element (FE) model of transcatheter aortic valves (TAV) was utilized to couple with SPH to simulate valve leaflet dynamics throughout the entire cardiac cycle. Comparative simulations were performed to investigate the impact of using FE-only models vs. FSI models, as well as an isotropic vs. an anisotropic leaflet material model in TAV simulations. From the results, substantial differences in leaflet kinematics between FE-only and FSI models were observed, and the FSI model could capture the realistic leaflet dynamic deformation due to its more accurate spatial and temporal loading conditions imposed on the leaflets. The stress and the strain distributions were similar between the FE and FSI simulations. However, the peak stresses were different due to the water hammer effect induced by the fluid inertia in the FSI model during the closing phase, which led to 13-28% lower peak stresses in the FE-only model compared to that of the FSI model. The simulation results also indicated that tissue anisotropy had a minor impact on hemodynamics of the valve. However, a lower tissue stiffness in the radial direction of the leaflets could reduce the leaflet peak stress caused by the water hammer effect. It is hoped that the developed FSI models can serve as an effective tool to better assess valve dynamics and optimize next generation TAV designs.
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Light-dependent changes in the leaflet movement rhythm of the plant Desmodium gyrans.
Sharma, Vijay Kumar; Bardal, Tom Kristian; Johnsson, Anders
2003-01-01
The movements of the lateral leaflets of the Indian telegraph plant Desmodium gyrans (L. F.) DC, have earlier been studied in detail with regards to the effects of chemicals, DC currents, and static magnetic fields. In the present paper we have discussed the oscillation of the lateral leaflets under the influence of white light of various light levels (0-75 micromol x m(-2) x s(-1)), produced by an array of LEDs (light emitting diodes). LEDs were used in contrast to fluorescense tubes as in earlier studies in order to minimize changes of wavelength when light intensity was decreased or increased. Furthermore, care was taken to ensure that the temperature in the experimental chamber was constant. When the oscillations were first monitored in bright light, the oscillations were found to be very rapid and with decreasing light intensity the oscillations slowed down. For light levels lower than about 20 micromol x m(-2) x s(-1) the period of the oscillation of the lateral leaflets was almost constant (or even decreased slightly towards complete darkness). We also show that the oscillations could completely stop under prolonged darkness (for longer than about 6 h) and that such halted oscillations could be restarted in most of the leaflets when he light was turned back on. Such stopping of the oscillation of the lateral leaflets in prolonged darkness suggests that these short period oscillations of the lateral leaflets could have a daily component and in natural environment these oscillations could serve the purpose of optimising the amount of light falling on the leaflets or/and facilitating transpiration of water through stomata. Such a finding could have an implication for the answer to the long standing question of adaptive significance of short period oscillation of the Indian telegraph plant Desmodium gyrans (L. F.) DC.
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Prediction of oxygen distribution in aortic valve leaflet considering diffusion and convection.
Wang, Ling; Korossis, Sotirios; Fisher, John; Ingham, Eileen; Jin, Zhongmin
2011-07-01
Oxygen supply and transport is an important consideration in the development of tissue engineered constructs. Previous studies from our group have focused on the effect of tissue thickness on the oxygen diffusion within a three-dimensional aortic valve leaflet model, and highlighted the necessity for additional transport mechanisms such as oxygen convection. The aims of this study were to investigate the effect of interstitial fluid flow within the aortic valve leaflet, induced by the cyclic loading of the leaflet, on oxygen transport. Indentation testing and finite element modelings were employed to derive the biphasic properties of the leaflet tissue. The biphasic properties were subsequently used in the computational modeling of oxygen convection in the leaflet, which was based on the effective interstitial fluid velocity and the tissue deformation. Subsequently, the oxygen profile was predicted within the valve leaflet model by solving the diffusion and convection equation simultaneously utilizing the finite difference method. The compression modulus (E) and hydraulic permeability were determined by adapting a finite element model to the experimental indentation test on valvular tissue, E = 0.05MPa, and k =2.0 mm4/Ns. Finite element model of oxygen convection in valvular tissue incorporating the predicted biphasic properties was developed and the interstitial fluid flow rate was calculated falling in range of 0.025-0.25 mm/s depending on the tissue depth. Oxygen distribution within valvular tissue was predicted using one-dimensional oxygen diffusion model taking into consider the interstitial fluid effect. It was found that convection did enhance the oxygen transport in valvular tissue by up to 68% increase in the minimum oxygen tension within the tissue, depending on the strain level of the tissue as reaction of the magnitude and frequencies of the cardiac loading. The effective interstitial fluid velocity was found to play an important role in enhancing the oxygen transport within the valve leaflet. Such an understanding is important in the development of valvular tissue engineered constructs.
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Measurement and reconstruction of the leaflet geometry for a pericardial artificial heart valve.
Jiang, Hongjun; Campbell, Gord; Xi, Fengfeng
2005-03-01
This paper describes the measurement and reconstruction of the leaflet geometry for a pericardial heart valve. Tasks involved include mapping the leaflet geometries by laser digitizing and reconstructing the 3D freeform leaflet surface based on a laser scanned profile. The challenge is to design a prosthetic valve that maximizes the benefits offered to the recipient as compared to the normally operating naturally-occurring valve. This research was prompted by the fact that artificial heart valve bioprostheses do not provide long life durability comparable to the natural heart valve, together with the anticipated benefits associated with defining the valve geometries, especially the leaflet geometries for the bioprosthetic and human valves, in order to create a replicate valve fabricated from synthetic materials. Our method applies the concept of reverse engineering in order to reconstruct the freeform surface geometry. A Brown & Shape coordinate measuring machine (CMM) equipped with a HyMARC laser-digitizing system was used to measure the leaflet profiles of a Baxter Carpentier-Edwards pericardial heart valve. The computer software, Polyworks was used to pre-process the raw data obtained from the scanning, which included merging images, eliminating duplicate points, and adding interpolated points. Three methods, creating a mesh model from cloud points, creating a freeform surface from cloud points, and generating a freeform surface by B-splines are presented in this paper to reconstruct the freeform leaflet surface. The mesh model created using Polyworks can be used for rapid prototyping and visualization. To fit a freeform surface to cloud points is straightforward but the rendering of a smooth surface is usually unpredictable. A surface fitted by a group of B-splines fitted to cloud points was found to be much smoother. This method offers the possibility of manually adjusting the surface curvature, locally. However, the process is complex and requires additional manipulation. Finally, this paper presents a reverse engineered design for the pericardial heart valve which contains three identical leaflets with reconstructed geometry.
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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 with http://www.isrctn.org/ and ID is ISRCTN76616358.
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Labrosse, Michel R; Jafar, Reza; Ngu, Janet; Boodhwani, Munir
2016-11-01
Aortic valve (AV) repair has become an attractive option to correct aortic insufficiency. Yet, cusp reconstruction with various cusp replacement materials has been associated with greater long-term repair failures, and it is still unknown how such materials mechanically compare with native leaflets. We used planar biaxial testing to characterize six clinically relevant cusp replacement materials, along with native porcine AV leaflets, to ascertain which materials would be best suited for valve repair. We tested at least six samples of: 1) fresh autologous porcine pericardium (APP), 2) glutaraldehyde fixed porcine pericardium (GPP), 3) St Jude Medical pericardial patch (SJM), 4) CardioCel patch (CC), 5) PeriGuard (PG), 6) Supple PeriGuard (SPG) and 7) fresh porcine AV leaflets (PC). We introduced efficient displacement-controlled testing protocols and processing, as well as advanced convexity requirements on the strain energy functions used to describe the mechanical response of the materials under loading. The proposed experimental and data processing pipeline allowed for a robust in-plane characterization of all the materials tested, with constants determined for two Fung-like hyperelastic, anisotropic strain energy models. Overall, CC and SPG (respectively PG) patches ranked as the closest mechanical equivalents to young (respectively aged) AV leaflets. Because the native leaflets as well as CC, PG and SPG patches exhibit significant anisotropic behaviors, it is suggested that the fiber and cross-fiber directions of these replacement biomaterials be matched with those of the host AV leaflets. The long-term performance of cusp replacement materials would ideally be evaluated in large animal models for AV disease and cusp repair, and over several months or more. Given the unavailability and impracticality of such models, detailed information on stress-strain behavior, as studied herein, and investigations of durability and valve dynamics will be the best surrogates, as they have been for prosthetic valves. Overall, comparison with Fig. 3 suggests that CC and SPG (respectively PG) patches may be the closest mechanical equivalents to young (respectively aged) AV leaflets. Interestingly, the thicknesses of these materials are close to those reported for porcine and younger human AV leaflets, which may facilitate surgical implantation, by contrast to the thinner APP which has poor handling qualities. Because the native leaflets as well as CC, PG and SPG patches exhibit anisotropic behaviors, from a mechanistic perspective alone, it stands to reason that cardiac surgeons should seek to intraoperatively match the fiber and cross-fiber directions of these replacement biomaterials with those of the repaired AV leaflets. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Meijer, Marieke; Dingemans, Milou M.L.; van den Berg, Martin; Westerink, Remco H.S.
2014-01-01
Humans are exposed to distinct structural classes of insecticides with different neurotoxic modes of action. Because calcium homeostasis is essential for proper neuronal function and development, we investigated the effects of insecticides from different classes (pyrethroid: (α-)cypermethrin; organophosphate: chlorpyrifos; organochlorine: endosulfan; neonicotinoid: imidacloprid) and mixtures thereof on the intracellular calcium concentration ([Ca2+]i). Effects of acute (20 min) exposure to (mixtures of) insecticides on basal and depolarization-evoked [Ca2+]i were studied in vitro with Fura-2-loaded PC12 cells and high resolution single-cell fluorescence microscopy. The data demonstrate that cypermethrin, α-cypermethrin, endosulfan, and chlorpyrifos concentration-dependently decreased depolarization-evoked [Ca2+]i, with 50% (IC50) at 78nM, 239nM, 250nM, and 899nM, respectively. Additionally, acute exposure to chlorpyrifos or endosulfan (10μM) induced a modest increase in basal [Ca2+]i, amounting to 68 ± 8nM and 53 ± 8nM, respectively. Imidacloprid did not disturb basal or depolarization-evoked [Ca2+]i at 10μM. Following exposure to binary mixtures, effects on depolarization-evoked [Ca2+]i were within the expected effect additivity range, whereas the effect of the tertiary mixture was less than this expected additivity effect range. These results demonstrate that different types of insecticides inhibit depolarization-evoked [Ca2+]i in PC12 cells by inhibiting voltage-gated calcium channels (VGCCs) in vitro at concentrations comparable with human occupational exposure levels. Moreover, the effective concentrations in this study are below those for earlier described modes of action. Because inhibition of VGCCs appears to be a common and potentially additive mode of action of several classes of insecticides, this target should be considered in neurotoxicity risk assessment studies. PMID:24913802
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Dampney, Roger A L; Furlong, Teri M; Horiuchi, Jouji; Iigaya, Kamon
2013-04-01
The midbrain periaqueductal grey (PAG) contains four longitudinal columns, referred to as the dorsomedial (dmPAG), dorsolateral (dlPAG), lateral (lPAG) and ventrolateral (vlPAG) subdivisions, which collectively have a pivotal role in integrating behavioural and physiological responses to external stressors as well as other functions. This review is focussed on the dlPAG, which is believed to be an important component of the central mechanisms that generate the defensive response to acute psychological stressors, such as the presence of a predator or other immediate threat. The anatomical connections of the dlPAG are highly specific and distinctly different from those of the other PAG subregions. The chemical properties of the dlPAG are also distinctly different from the other PAG subregions (e.g. there is a very high density of neurons that synthesize nitric oxide in the dlPAG but very few such neurons in the other PAG subregions). Recent functional studies have demonstrated that neurons in the dlPAG exert a powerful control over both sympathetic and respiratory activity, and that the pattern of the evoked respiratory changes is also distinctly different from those evoked from other PAG subregions. These studies also showed that the sympathetic and respiratory changes evoked from the dlPAG are highly correlated, suggesting the possibility that a common population of "command neurons" within this region may generate the sympathetic and respiratory changes that accompany defensive behavioural responses to acute psychological stressors. Finally, although the anatomical connections and functional properties of the dlPAG are distinctly different from the other PAG subregions, they have many similarities with adjacent parts of the superior colliculus, suggesting that the dlPAG and deep layers of the superior colliculus may be part of a common defence system in the midbrain. Copyright © 2013 Elsevier B.V. All rights reserved.
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Phylogeny of the genus Pistacia as determined from analysis of the chloroplast genome
Parfitt, Dan E.; Badenes, Maria L.
1997-01-01
Classification within the genus Pistacia has been based on leaf morphology and geographical distribution. Molecular genetic tools (PCR amplification followed by restriction analysis of a 3.2-kb region of variable chloroplast DNA, and restriction fragment length polymorphism analysis of the Pistacia cpDNA with tobacco chloroplast DNA probes) provided a new set of variables to study the phylogenetic relationships of 10 Pistacia species. Both parsimony and cluster analyses were used to divide the genus into two major groups. P. vera was determined to be the least derived species. P. weinmannifolia, an Asian species, is most closely related to P. texana and P. mexicana, New World species. These three species share a common origin, suggesting that a common ancestor of P. texana and P. mexicana originated in Asia. P. integerrima and P. chinensis were shown to be distinct whereas the pairs of species were monophyletic within each of two tertiary groups, P. vera:P. khinjuk and P. mexicana:P. texana. An evolutionary trend from large to small nuts and leaves with few, large leaflets to many, small leaflets was supported. The genus Pistacia was shown to have a low chloroplast DNA mutation rate: 0.05–0.16 times that expected of annual plants. PMID:9223300
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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.
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López Cascales, J J; Otero, T F; Smith, Bradley D; González, Carlos; Márquez, M
2006-02-09
The study of asymmetric lipid bilayers is of a crucial importance due to the great number of biological process in which they are involved such as exocytosis, intracellular fusion processes, phospholipid-protein interactions, and signal transduction pathway. In addition, the loss of this asymmetry is a hallmark of the early stages of apoptosis. In this regard, a model of an asymmetric lipid bilayer composed of DPPC and DPPS was simulated by molecular dynamics simulation. Thus, the asymmetric membrane was modeled by 264 lipids, of which 48 corresponded to DPPS- randomly distributed in the same leaflet with 96 DPPC. In the other leaflet, 120 DPPC were placed without DPPS-. Due to the presence of a net charge of -1 for the DPPS- in physiological conditions, 48 Na+ were introduced into the system to balance the charge. To ascertain whether the presence of the DPPS- in only one of the two leaflets perturbs the properties of the DPPC in the other leaflet composed only of DPPC, different properties were studied, such as the atomic density of the different components across the membrane, the electrostatic potential across the membrane, the translational diffusion of DPPC and DPPS, the deuterium order parameters, lipid hydration, and lipid-lipid charge bridges. Thus, we obtained that certain properties such as the surface area lipid molecule, lipid head orientation, order parameter, translational diffusion coefficient, or lipid hydration of DPPC in the leaflet without DPPS remain unperturbed by the presence of DPPS in the other leaflet, compared with a DPPC bilayer. On the other hand, in the leaflet containing DPPS, some of the DPPC properties were strongly affected by the presence of DPPS such as the order parameter or electrostatic potential.
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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
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Evolving Techniques for Mitral Valve Reconstruction
Galloway, Aubrey C.; Grossi, Eugene A.; Bizekis, Costas S.; Ribakove, Greg; Ursomanno, Patricia; Delianides, Julie; Baumann, F. Gregory; Spencer, Frank C.; Colvin, Stephen B.
2002-01-01
Objective To analyze the effectiveness of new techniques of mitral valve reconstruction (MVR) that have evolved over the last decade, such as aggressive anterior leaflet repair and minimally invasive surgery using an endoaortic balloon occluder. Summary Background Data MVR via conventional sternotomy has been an established treatment for mitral insufficiency for over 20 years, primarily for the treatment of patients with posterior leaflet prolapse. Methods Between June 1980 and June 2001, 1,195 consecutive patients had MVR with ring annuloplasty. Conventional sternotomy was used in 843 patients, minimally invasive surgery in 352 (since June 1996). Anterior leaflet repair was performed in 374 patients, with increasing use over the last 10 years. Follow-up was 100% complete (mean 4.6 years, range 0.5–20.5). Results Hospital mortality was 4.7% overall and 1.4% for isolated MVR (1.1% for minimally invasive surgery vs. 1.6% for conventional sternotomy;P = .4). Multivariate analysis showed the factors predictive of increased operative risk to be age, NYHA functional class, concomitant procedures, and previous cardiac surgery. The 5-year results for freedom from cardiac death, reoperation, and valve-related complications among the 782 patients with degenerative etiology are, respectively, as follows (P > .05 for all end points): for anterior leaflet repair, 93%, 94%, 90%; for no anterior leaflet repair, 91%, 92%, 91%; for minimally invasive surgery, 97%, 89%, 93%; and for conventional sternotomy, 93%, 94%, 90%. Conclusions These findings indicate that late results of MVR after minimally invasive surgery and after anterior leaflet repair are equivalent to those achievable with conventional sternotomy and posterior leaflet repair. These options significantly expand the range of patients suitable for mitral valve repair surgery and give further evidence to support wider use of minimally invasive techniques. PMID:12192315
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Courtman, D W; Pereira, C A; Omar, S; Langdon, S E; Lee, J M; Wilson, G J
1995-12-01
Heart valve substitutes of biological origin often fail by degenerative mechanisms. Many authors have hypothesized that mechanical fatigue and structural degradation are instrumental to in vivo failure. Since the properties of the structural matrix at implantation may predetermine failure, we have examined the ultrastructure, fracture, mechanics, and uniaxial high-strain-rate viscoelastic properties of: (1) fresh, (2) cryopreserved, and (3) cellular extracted porcine aortic valve leaflets. The cellular extraction process is being developed in order to reduce immunological attack and calcification. Cryopreservation causes cellular disruption and necrotic changes throughout the tissue, whereas extraction removes all cells and lipid membranes. Both processes leave an intact collagen and elastin structural matrix and preserve the high-strain-rate viscoelastic characteristics of the fresh leaflets. Extraction does cause a 20% reduction in the fracture tension and increases tissue extensibility, with the percent strain at fracture rising to 45.3 +/- 4 (mean +/- SEM) from 31.5 +/- 3 for fresh leaflets. However, extraction does preserve matrix structure and mechanics over the physiological loading range. Glutaraldehyde fixation produces increased extensibility, increased elastic behavior, and, when applied to extracted leaflets, it causes a marked drop in fracture tension, to 50% of that for fresh leaflets. The combination of extraction and fixation may lead to early degenerative failure. The cellular extraction technique alone may be a useful alternative to glutaraldehyde fixation in preparing bioprosthetic heart valves.
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Explaining how brain stimulation can evoke memories.
Jacobs, Joshua; Lega, Bradley; Anderson, Christopher
2012-03-01
An unexplained phenomenon in neuroscience is the discovery that electrical stimulation in temporal neocortex can cause neurosurgical patients to spontaneously experience memory retrieval. Here we provide the first detailed examination of the neural basis of stimulation-induced memory retrieval by probing brain activity in a patient who reliably recalled memories of his high school (HS) after stimulation at a site in his left temporal lobe. After stimulation, this patient performed a customized memory task in which he was prompted to retrieve information from HS and non-HS topics. At the one site where stimulation evoked HS memories, remembering HS information caused a distinctive pattern of neural activity compared with retrieving non-HS information. Together, these findings suggest that the patient had a cluster of neurons in his temporal lobe that help represent the "high school-ness" of the current cognitive state. We believe that stimulation here evoked HS memories because it altered local neural activity in a way that partially mimicked the normal brain state for HS memories. More broadly, our findings suggest that brain stimulation can evoke memories by recreating neural patterns from normal cognition.
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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.
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Flow-Induced Mitral Leaflet Motion in Hypertrophic Cardiomyopathy
NASA Astrophysics Data System (ADS)
Meschini, Valentina; Mittal, Rajat; Verzicco, Roberto
2017-11-01
Hypertrophic cardiomyopathy (HCM) is considered the cause of sudden cardiac death in developed countries. Clinically it is found to be related to the thickening of the intra-ventricular septum combined with elongated mitral leaflets. During systole the low pressure, induced by the abnormal velocities in the narrowed aortic channel, can attract one or both the mitral leaflets causing the aortic obstruction and sometimes instantaneous death. In this paper a fluid structure interaction model for the flow in the left ventricle with a native mitral valve is employed to investigate the physio-pathology of HCM. The problem is studied using direct numerical simulations of the Navier-Stokes equations with a two-way coupled structural solver based on interaction potential approach for the structure dynamics. Simulations are performed for two different degrees of hypertrophy, and two values of pumping efficiency. The leaflets dynamics and the ventricle deformation resulting from the echocardiography of patients affected by HCM are well captured by the simulations. Moreover, the procedures of leaflets plication and septum myectomy are simulated in order to get insights into the efficiency and reliability of such surgery.
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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
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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.
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Photosynthetic carbon metabolism in leaflets, stipules and tendrils of Pisum sativum L
DOE Office of Scientific and Technical Information (OSTI.GOV)
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 reducedmore » 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.« less
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Design and ergonomics of package inserts of drugs in Brazil: a reality in construction.
da Silva, Charles Ricardo Leite; Soares, Marcelo Marcio
2012-01-01
This research deals with the design of leaflets of medicines, evidencing the problems resulting from the lack of Brazilian normalization to promote the use of the graphical representation of instructional texts warnings. It approaches studies related to the effectiveness and efficiency of information systems, highlighting the semiotics and the cultural and informational ergonomics. The analysis of the context uses as method, an analytical study on selected warnings of thirty leaflets of medicines, followed by interviews lead with the public managers involved with the regulation of the pharmaceutical companies, and two experiments with users performed in city of Recife, in State of Pernambuco: one aiming at to identify how they interact with the leaflets of medicines, and the second one testing their understanding concerning standardized illustrations in the United States and the South Africa. The results show the need for improvements in presentation and graphic representation of leaflets of medicines, powering them to the role of communication, to ensure the consumption of medicine safely by its users. The conclusion congregates parameters and recommendations for the graphic representation of warnings in leaflets of medicines in Brazil.
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Neural substrates underlying fear-evoked freezing: the periaqueductal grey–cerebellar link
Koutsikou, Stella; Crook, Jonathan J; Earl, Emma V; Leith, J Lianne; Watson, Thomas C; Lumb, Bridget M; Apps, Richard
2014-01-01
The central neural pathways involved in fear-evoked behaviour are highly conserved across mammalian species, and there is a consensus that understanding them is a fundamental step towards developing effective treatments for emotional disorders in man. The ventrolateral periaqueductal grey (vlPAG) has a well-established role in fear-evoked freezing behaviour. The neural pathways underlying autonomic and sensory consequences of vlPAG activation in fearful situations are well understood, but much less is known about the pathways that link vlPAG activity to distinct fear-evoked motor patterns essential for survival. In adult rats, we have identified a pathway linking the vlPAG to cerebellar cortex, which terminates as climbing fibres in lateral vermal lobule VIII (pyramis). Lesion of pyramis input–output pathways disrupted innate and fear-conditioned freezing behaviour. The disruption in freezing behaviour was strongly correlated to the reduction in the vlPAG-induced facilitation of α-motoneurone excitability observed after lesions of the pyramis. The increased excitability of α-motoneurones during vlPAG activation may therefore drive the increase in muscle tone that underlies expression of freezing behaviour. By identifying the cerebellar pyramis as a critical component of the neural network subserving emotionally related freezing behaviour, the present study identifies novel neural pathways that link the PAG to fear-evoked motor responses. PMID:24639484
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Topography of itch: evidence of distinct coding for pruriception in the trigeminal nerve
Andersen, Hjalte H.; Elberling, Jesper; Lo Vecchio, Silvia
2017-01-01
Introduction: Little is known about the topographical distribution of pruriception (in particular for nonhistaminergic itch), although conditions with chronic itch frequently occur in distinct anatomic and often bilateral patterns. This study aimed to investigate regional differences in the sensitivity to itch stimuli by assessing the intensity of itch, pain, and cutaneous neurogenic flare evoked by histamine and cowhage in different anatomic regions in 20 healthy volunteers. Methods: Itch was induced by 1% histamine applied with a prick lancet or by insertion of 25±5 cowhage spicules in 4 regions: volar/dorsal forearm, lower back, and chin. The duration and intensity of itch and pain following each pruritic stimulus were measured by a continuous visual analogue scale (VAS0-100). Sensitivity to touch-evoked itch was assessed by von Frey filaments and cutaneous flare was quantified by full-field laser perfusion imaging. Results: Peak itch intensity was lower at the chin (19.4±3.6) compared with other areas (mean of 3 locations; 41.3±4.4), independently of whether histamine or cowhage was applied (P<0.01). Baseline sensitivity to touch-evoked itch was higher on the chin (P<0.01), but here hyperknesis did not develop in contrast to other areas (P<0.05). Cutaneous flare was more intense but had a smaller dispersion at the chin, compared with other areas (P<0.01). Discussion: In conclusion, sensitivity to histaminergic and non-histaminergic itch diverges considerably between body regions. Lower density of pruriceptive CMH and CMI-neurons or distinct neuronal substrates for itch in the mandibular part of the trigeminal area may explain the observed reduced itch and vasomotor responses. PMID:29862321
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Scott, Sophie K; Lavan, Nadine; Chen, Sinead; McGettigan, Carolyn
2014-12-01
Laughter is often considered to be the product of humour. However, laughter is a social emotion, occurring most often in interactions, where it is associated with bonding, agreement, affection, and emotional regulation. Laughter is underpinned by complex neural systems, allowing it to be used flexibly. In humans and chimpanzees, social (voluntary) laughter is distinctly different from evoked (involuntary) laughter, a distinction which is also seen in brain imaging studies of laughter. Copyright © 2014 Elsevier Ltd. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Krebs, M.O.; Trovero, F.; Desban, M.
1991-05-01
Striosome- and matrix-enriched striatal zones were defined in coronal and sagittal brain sections of the rat, on the basis of {sup 3}H-naloxone binding to mu-opiate receptors (a striosome-specific marker). Then, using a new in vitro microsuperfusion device, the NMDA (50 microM)-evoked release of newly synthesized {sup 3}H-dopamine ({sup 3}H-DA) was examined in these four striatal areas under Mg(2+)-free conditions. The amplitudes of the responses were different in striosomal (171 +/- 6% and 161 +/- 5% of the spontaneous release) than in matrix areas (223 +/- 6% and 248 +/- 12%), even when glycine (1 or 100 microM) was coapplied (inmore » the presence of 1 microM strychnine). In the four areas, the NMDA-evoked release of {sup 3}H-DA was blocked completely by Mg{sup 2}{sup +} (1 mM) or (+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine maleate (MK-801; 1 microM) and almost totally abolished by kynurenate (100 microM). Because the tetrodotoxin (TTX)-resistant NMDA-evoked release of {sup 3}H-DA was similar in striosome- (148 +/- 5% and 152 +/- 6%) or matrix-enriched (161 +/- 5% and 156 +/- 7%) areas, the indirect (TTX-sensitive) component of NMDA-evoked responses, which involves striatal neurons and/or afferent fibers, seems more important in the matrix- than in the striosome-enriched areas. The modulation of DA release by cortical glutamate and/or aspartate-containing inputs through NMDA receptors in the matrix appears thus to be partly distinct from that observed in the striosomes, providing some functional basis for the histochemical striatal heterogeneity.« less
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Quantification and comparison of the mechanical properties of four human cardiac valves.
Pham, Thuy; Sulejmani, Fatiesa; Shin, Erica; Wang, Di; Sun, Wei
2017-05-01
Although having the same ability to permit unidirectional flow within the heart, the four main valves-the mitral valve (MV), aortic (AV), tricuspid (TV) and pulmonary (PV) valves-experience different loading conditions; thus, they exhibit different structural integrity from one another. Most research on heart valve mechanics have been conducted mainly on MV and AV or an individual valve, but none quantify and compare the mechanical and structural properties among the four valves from the same aged patient population whose death was unrelated to cardiovascular disease. A total of 114 valve leaflet samples were excised from 12 human cadavers whose death was unrelated to cardiovascular disease (70.1±3.7years old). Tissue mechanical and structural properties were characterized by planar biaxial mechanical testing and histological methods. The experimental data were then fitted with a Fung-type constitutive model. The four valves differed substantially in thickness, degree of anisotropy, and stiffness. The leaflets of the left heart (the AV leaflets and the anterior mitral leaflets, AML) were significantly stiffer and less compliant than their counterparts in the right heart. TV leaflets were the most extensible and isotropic, while AML and AV leaflets were the least extensible and the most anisotropic. Age plays a significant role in the reduction of leaflet stiffness and extensibility with nearly straightened collagen fibers observed in the leaflet samples from elderly groups (65years and older). Results from 114 human leaflet samples not only provided a baseline quantification of the mechanical properties of aged human cardiac valves, but also offered a better understanding of the age-dependent differences among the four valves. It is hoped that the experimental data collected and the associated constitutive models in this study can facilitate future studies of valve diseases, treatments and the development of interventional devices. Most research on heart valve mechanics have been conducted mainly on mitral and aortic valves or an individual valve, but none quantify and compare the mechanical and structural properties among the four valves from the same relatively healthy elderly patient population. In this study, the mechanical and microstructural properties of 114 leaflets of aortic, mitral, pulmonary and tricuspid valves from 12 human cadaver hearts were mechanically tested, analyzed and compared. Our results not only provided a baseline quantification of the mechanical properties of aged human valves, but a age range between patients (51-87years) also offers a better understanding of the age-dependent differences among the four valves. It is hoped that the obtained experimental data and associated constitutive parameters can facilitate studies of valve diseases, treatments and the development of interventional devices. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Mediratta, Anuj; Addetia, Karima; Yamat, Megan; Moss, Joshua D; Nayak, Hemal M; Burke, Martin C; Weinert, Lynn; Maffessanti, Francesco; Jeevanandam, Valluvan; Mor-Avi, Victor; Lang, Roberto M
2014-04-01
This study sought to: 1) determine the feasibility of using 3-dimensional transthoracic echocardiography (3D TTE) in patients with implantable cardiac resynchronization devices, pacemakers, and defibrillators to visualize the device leads in the right heart and their position relative to the tricuspid valve leaflets; 2) determine the prevalence of different lead positions; and 3) study the relationship between lead location and tricuspid regurgitation (TR) severity. Pacemaker, defibrillator, and cardiac resynchronization device implantation is currently guided by fluoroscopy, not allowing targeted lead positioning relative to the tricuspid valve leaflets. These leads have been reported to cause TR of variable degrees, but echocardiography is not routinely used to elucidate the mechanisms of lead interference with tricuspid valve leaflets in individual patients. 3D TTE full-volume images of the right ventricle and/or zoomed images of the tricuspid valve were obtained in 121 patients with implanted devices. Images were viewed offline to determine the position of the device-lead relative to the tricuspid valve leaflets. Severity of TR was estimated on the basis of vena contracta measurements. 3D TTE clearly depicted lead position in 90% of patients. The right ventricular lead was impinging on either the posterior (20%) or septal (23%) leaflet or was not interfering with leaflet motion (53%) when positioned near the posteroseptal commissure or in the central portion of the tricuspid valve orifice. In the remaining patients, leads were impinging on the anterior leaflet (4%) or positioned in either the anteroposterior or anteroseptal commissure (3%). Leads interfering with normal leaflet mobility were associated with more TR than nonimpinging leads (vena contracta: median 0.62 cm [1st and 3rd quartiles: 0.51, 0.84 cm] vs. 0.27 cm [1st and 3rd quartiles: 0.00, 0.48 cm]; p < 0.001). 3D TTE showed a clear association between device lead position and TR. To minimize TR induced by device-leads, 3D TTE guidance should be considered for placement in a commissural position. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
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Marazzi, Brigitte; Conti, Elena; Sanderson, Michael J.; McMahon, Michelle M.; Bronstein, Judith L.
2013-01-01
Background and Aims Plants display a wide range of traits that allow them to use animals for vital tasks. To attract and reward aggressive ants that protect developing leaves and flowers from consumers, many plants bear extrafloral nectaries (EFNs). EFNs are exceptionally diverse in morphology and locations on a plant. In this study the evolution of EFN diversity is explored by focusing on the legume genus Senna, in which EFNs underwent remarkable morphological diversification and occur in over 80 % of the approx. 350 species. Methods EFN diversity in location, morphology and plant ontogeny was characterized in wild and cultivated plants, using scanning electron microscopy and microtome sectioning. From these data EFN evolution was reconstructed in a phylogenetic framework comprising 83 Senna species. Key Results Two distinct kinds of EFNs exist in two unrelated clades within Senna. ‘Individualized’ EFNs (iEFNs), located on the compound leaves and sometimes at the base of pedicels, display a conspicuous, gland-like nectary structure, are highly diverse in shape and characterize the species-rich EFN clade. Previously overlooked ‘non-individualized’ EFNs (non-iEFNs) embedded within stipules, bracts, and sepals are cryptic and may represent a new synapomorphy for clade II. Leaves bear EFNs consistently throughout plant ontogeny. In one species, however, early seedlings develop iEFNs between the first pair of leaflets, but later leaves produce them at the leaf base. This ontogenetic shift reflects our inferred diversification history of iEFN location: ancestral leaves bore EFNs between the first pair of leaflets, while leaves derived from them bore EFNs either between multiple pairs of leaflets or at the leaf base. Conclusions EFNs are more diverse than previously thought. EFN-bearing plant parts provide different opportunities for EFN presentation (i.e. location) and individualization (i.e. morphology), with implications for EFN morphological evolution, EFN–ant protective mutualisms and the evolutionary role of EFNs in plant diversification. PMID:23104672
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Translanguaging in Bilingual Schools in Wales
ERIC Educational Resources Information Center
Jones, Bryn
2017-01-01
This article examines the use of translanguaging as a pedagogical tool to support learning within bilingual classrooms in schools in Wales. Translanguaging is considered within non-pedagogic and pedagogic school contexts; hence, a distinction is made between universal and classroom translanguaging. Translanguaging has evoked debate surrounding the…
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Blake, Khandis R; Yih, Jennifer; Zhao, Kun; Sung, Billy; Harmon-Jones, Cindy
2017-09-01
Skin-transmitted pathogens have threatened humans since ancient times. We investigated whether skin-transmitted pathogens were a subclass of disgust stimuli that evoked an emotional response that was related to, but distinct from, disgust and fear. We labelled this response "the heebie jeebies". In Study 1, coding of 76 participants' experiences of disgust, fear, and the heebie jeebies showed that the heebie jeebies was elicited by unique stimuli which produced skin-crawling sensations and an urge to protect the skin. In Experiment 2,350 participants' responses to skin-transmitted pathogen, fear-inducing, and disgust-inducing vignettes showed that the vignettes elicited sensations and urges which loaded onto heebie jeebies, fear, and disgust factors, respectively. Experiment 3 largely replicated findings from Experiment 2 using video stimuli (178 participants). Results are consistent with the notion that skin-transmitted pathogens are a subclass of disgust stimuli which motivate behaviours that are functionally consistent with disgust yet qualitatively distinct.
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Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation.
Stamm, Christof; Pasic, Miralem; Buz, Semih; Hetzer, Roland
2015-09-01
A patient required emergency mitral valve replacement and extracorporeal membrane oxygenation (ECMO) support for acute biventricular failure. The left ventricular (LV) vent inserted via the left upper pulmonary vein induced thrombotic immobilization of a prosthetic valve leaflet, with significant intra-prosthesis regurgitation after ECMO explantation. Therefore, the left atrium was opened on the beating heart during conventional extracorporeal circulation, all prosthesis leaflets were excised and a 29-mm expandable Edwards Sapien prosthesis was inserted within the scaffold of the original prosthesis under direct vision. This case illustrates the benefits and potential problems of LV venting on ECMO support, and a rapid and safe way of replacing the prosthesis leaflets in a critical situation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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Leaflet escape in a new bileaflet mechanical valve: TRI technologies.
Bottio, Tomaso; Casarotto, Dino; Thiene, Gaetano; Caprili, Luca; Angelini, Annalisa; Gerosa, Gino
2003-05-13
Leaflet escape is a mode of structural valve failure for mechanical prostheses. This complication previously has been reported for both monoleaflet and bileaflet valve models. We report 2 leaflet escape occurrences observed in 2 patients who underwent valve replacement with a TRI Technologies valve prosthesis. At the University of Padua, between November 2000 and February 2002, 36 TRI Technologies valve prostheses (26 aortic and 10 mitral) were implanted in 34 patients (12 women and 22 men) with a mean age of 59.9+/-10.3 years (range, 30 to 75 years). There were 5 deaths: 3 in hospital, 1 early after discharge, and 1 late. Two patients experienced a catastrophic prosthetic leaflet escape; the first patient was a 52-year-old man who died 10 days after aortic valve and ascending aorta replacement, and the second was a 58-year-old man who underwent a successful emergency reoperation 20 months after mitral valve replacement. Examination of the explanted prostheses showed in both cases a leaflet escape caused by a leaflet's pivoting system fracture. Prophylactic replacement was then successfully accomplished so far in 12 patients, without evidence of structural valve failure in any of them. Among other significant postoperative complications, we observed 3 major thromboembolisms, 1 hemorrhage, and 1 paravalvular leak. These catastrophes prompted us to interrupt the implantation program, and they cast a shadow on the durability of the TRI Technologies valve prosthesis because of its high risk of structural failure.
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Robotic Posterior Mitral Leaflet Repair: Neochordal versus Resectional Techniques
Mihaljevic, Tomislav; Pattakos, Gregory; Gillinov, A. Marc; Bajwa, Gurjyot; Planinc, Mislav; Williams, Sarah J.; Blackstone, Eugene H.
2013-01-01
Background Resectional techniques are the established method of posterior mitral valve leaflet repair for degenerative disease; however, use of neochordae in a robotically assisted approach is gaining acceptance because of its versatility for difficult multi-segment disease. The purposes of this study were to compare the versatility, safety, and effectiveness of neochordal vs. resectional techniques for robotic posterior mitral leaflet repair. Methods From 12/2007 to 7/2010, 334 patients underwent robotic posterior mitral leaflet repair for degenerative disease by a resectional (n=248) or neochordal (n=86) technique. Outcomes were compared unadjusted and after propensity score matching. Results Neochordae were more likely to be used than resection in patients with two (28% vs. 13%, P=.002) or three (3.7% vs. 0.87%, P=.08) diseased posterior leaflet segments. Three resection patients (0.98%) but no neochordal patient required reoperation for hemodynamically significant systolic anterior motion (SAM). Residual mitral regurgitation (MR) at hospital discharge was similar for matched neochordal vs. resection patients (P=.14) (MR 0+, 82% vs. 89%; MR 1+, 14% vs. 8.2%; MR 2+, 2.3% vs. 2.6%; one neochordal patient had 4+ MR and was reoperated). Among matched patients, postoperative mortality and morbidity were similarly low. Conclusion Compared with a resectional technique, robotic posterior mitral leaflet repair with neochordae is associated with shorter operative times and no occurrence of SAM. The versatility, effectiveness, and safety of this repair make it a good choice for patients with advanced multi-segment disease. PMID:23103008
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Human auditory evoked potentials. I - Evaluation of components
NASA Technical Reports Server (NTRS)
Picton, T. W.; Hillyard, S. A.; Krausz, H. I.; Galambos, R.
1974-01-01
Fifteen distinct components can be identified in the scalp recorded average evoked potential to an abrupt auditory stimulus. The early components occurring in the first 8 msec after a stimulus represent the activation of the cochlea and the auditory nuclei of the brainstem. The middle latency components occurring between 8 and 50 msec after the stimulus probably represent activation of both auditory thalamus and cortex but can be seriously contaminated by concurrent scalp muscle reflex potentials. The longer latency components occurring between 50 and 300 msec after the stimulus are maximally recorded over fronto-central scalp regions and seem to represent widespread activation of frontal cortex.
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Assessment of the quality of medication information for patients in Spain.
Mira, José Joaquín; Lorenzo, Susana; Pérez-Jover, Virtudes; Navarro, Isabel; Martín de Rosales, Ana María; Lara, Catalina
2013-01-01
To analyze the extent to which Spanish leaflets and drug information on the Net met quality criteria. A descriptive study was conducted comparing readability (REA) and comprehensibility (COM) criteria of a random sample of 77 marketed products of the 12 active ingredients most frequently sold in 2010 in Spain. Leaflets were approved by the Spanish Agency for Medication (AEMPS). Flesch index, DISCERN, ELF, MIDAS and CIRF scales were used to evaluate quality criteria. COM assessment yielded between 63 and 77% of the maximum possible scores on the scales. None of the websites or leaflets met all the quality criteria of the DISCERN, CIRF or MIDAS scales. Four (3%) leaflets met all the 22 quality criteria of ELF. The leaflets showed shortcomings regarding: medication benefits (17 required substantial improvements, 31.5%), correct forms of storage (13, 24.1%), contraindications (12, 22.2%), side effects (11, 20.4%) and precautions to be taken (9, 16.7%). The quality of the information approved by the AEMPS is superior to that which can be found by surfing the Net. More specific information on precautions, complications and how to avoid common patient errors would allow patients the best chance to contribute to their own clinical safety.
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Absence of posterior tricuspid valve leaflet and valve reconstruction
Komoda, Takeshi; Stamm, Christof; Fleck, Eckart; Hetzer, Roland
2012-01-01
We report a rare case of the absence of a posterior tricuspid valve leaflet. A male patient, aged 46, suffering from severe tricuspid valve regurgitation (TR) of unknown aetiology and atrial septal aneurysm was referred to our hospital for surgery. On surgical inspection, the posterior tricuspid valve leaflet and its subvalvular apparatus were completely absent and only the valve annulus was seen in the corresponding position. The anterior and septal leaflets were normal. We successfully reconstructed the tricuspid valve as follows: the head of an anterior papillary muscle was approximated to the ventricular septum (Sebening stitch). After the approximation of the centre of the tricuspid annulus of the anterior leaflet to the tricuspid annulus on the opposite side, a sizer of 29 mm in diameter was easily passed through the anterior orifice. The posterior orifice was closed with running sutures (posterior annulorrhaphy after Hetzer). Before these procedures, we attempted to reconstruct the tricuspid valve with a posterior annulorrhaphy alone; however, valve competence was insufficient. A Sebening stitch was necessary to improve the valve competence. Echocardiography showed TR grade 1 at the patient's discharge from hospital and TR grade 1 to 2 at the follow-up, 10 months after the operation. PMID:22419794
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NASA Astrophysics Data System (ADS)
Vahidkhah, Koohyar; Abbasi, Mostafa; Barakat, Mohammed; Dvir, Danny; Azadani, Ali
2017-11-01
An increasingly recognized complication following surgical/transcatheter aortic valve replacement is thrombosis or blood clot formation on replacement valve leaflets. A predisposing factor in thrombus formation on biomaterial surfaces of a bioprosthetic heart valve is blood stasis. Longer residence time of blood provides an opportunity for platelets and agonists to accumulate to critical concentrations that leads to platelet activation and then thrombosis. In this study, we have developed a fluid-solid interaction (FSI) modeling approach, to quantify blood stasis on the leaflets of bioprosthetic aortic valves with different design operating in a patient-specific geometry. We have validated our FSI model against experimental measurements of valve opening/closing as well as in-vitro particle image velocimetry. We have also embedded in our method a model for transport of platelets and agonists (ADP, TxA2, and thrombin) and their interactions that result in platelets activation and adhesion to biomaterial bioprosthetic surfaces. We have provided quantitative evidence for the correlation between long residence of blood on bioprosthetic aortic valve leaflets and formation of high thrombogenicity risk regions on the leaflets that are characterized by accumulation of activated platelet.
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Effect of the mitral valve on diastolic flow patterns
DOE Office of Scientific and Technical Information (OSTI.GOV)
Seo, Jung Hee; Vedula, Vijay; Mittal, Rajat, E-mail: mittal@jhu.edu
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 diodemore » 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.« less
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Shabsigh, Muhammad; Lawrence, Cassidy; Rosero-Britton, Byron R; Kumar, Nicolas; Kimura, Satoshi; Durda, Michael Andrew; Essandoh, Michael
2016-01-01
Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm(2). Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9-54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier-Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair.
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Shabsigh, Muhammad; Lawrence, Cassidy; Rosero-Britton, Byron R.; Kumar, Nicolas; Kimura, Satoshi; Durda, Michael Andrew; Essandoh, Michael
2016-01-01
Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm2. Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9–54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier–Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair. PMID:27148540
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Rim, Yonghoon; Laing, Susan T; McPherson, David D; Kim, Hyunggun
2014-01-01
Mitral valve (MV) repair using expanded polytetrafluoroethylene sutures is an established and preferred interventional method to resolve the complex pathophysiologic problems associated with chordal rupture. We developed a novel computational evaluation protocol to determine the effect of the artificial sutures on restoring MV function following valve repair. A virtual MV was created using three-dimensional echocardiographic data in a patient with ruptured mitral chordae tendineae (RMCT). Virtual repairs were designed by adding artificial sutures between the papillary muscles and the posterior leaflet where the native chordae were ruptured. Dynamic finite element simulations were performed to evaluate pre- and post-repair MV function. Abnormal posterior leaflet prolapse and mitral regurgitation was clearly demonstrated in the MV with ruptured chordae. Following virtual repair to reconstruct ruptured chordae, the severity of the posterior leaflet prolapse decreased and stress concentration was markedly reduced both in the leaflet tissue and the intact native chordae. Complete leaflet coaptation was restored when four or six sutures were utilized. Computational simulations provided quantitative information of functional improvement following MV repair. This novel simulation strategy may provide a powerful tool for evaluation and prediction of interventional treatment for RMCT.
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Davies, M K; Lowry, P J; Littler, W A
1984-03-01
In a patient with severe tricuspid regurgitation and mild pulmonary stenosis due to carcinoid heart disease cross sectional echocardiography showed nodular thickening and coaptation of the tricuspid leaflets at the beginning of systole. The leaflets were, however, seen to be increasingly pulled apart as right ventricular systole proceeded. This finding, which is probably due to traction on the leaflets by the thickened chordae tendineae, is therefore a mechanism of valvular incompetence, perhaps accounting for the particularly severe tricuspid regurgitation seen in carcinoid heart disease.
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Catheter Entrapment During Posterior Mitral Leaflet Pushing Maneuver for MitraClip Implantation.
Castrodeza, Javier; Amat-Santos, Ignacio J; Tobar, Javier; Varela-Falcón, Luis H
2016-06-01
MitraClip (Abbott Vascular) therapy has been reported to be an effective procedure for mitral regurgitation, especially in high-risk patients. Recently, the novel pushing maneuver technique has been described for approaching restricted and short posterior leaflets with a pigtail catheter in order to facilitate grasping of the clip. However, complications or unexpected situations may occur. We report the case of an 84-year-old patient who underwent MitraClip implantation wherein the pushing maneuver was complicated by the clip accidentally gripping the pigtail catheter along with the two leaflets.
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Impact of Implantable Transvenous Device Lead Location on Severity of Tricuspid Regurgitation
Addetia, Karima; Maffessanti, Francesco; Mediratta, Anuj; Yamat, Megan; Weinert, Lynn; Moss, Joshua D.; Nayak, Hemal M.; Burke, Martin C.; Patel, Amit R.; Kruse, Eric; Jeevanandam, Valluvan; Mor-Avi, Victor; Lang, Roberto M.
2015-01-01
Background Implantable device leads can cause tricuspid regurgitation (TR) when they interfere with leaflet motion. The aim of this study was to determine whether lead-leaflet interference is associated with TR severity, independent of other causative factors of functional TR. Methods A total of 100 patients who underwent transthoracic two-dimensional and three-dimensional (3D) echocardiography of the tricuspid valve before and after lead placement were studied. Lead position was classified on 3D echocardiography as leaflet-interfering or noninterfering. TR severity was estimated by vena contracta (VC) width. Logistic regression analysis was used to identify factors associated with postdevice TR, including predevice VC width, right ventricular end-diastolic and end-systolic areas, fractional area change, right atrial size, tricuspid annular diameter, TR gradient, device lead age, and presence or absence of lead interference. Odds ratios were used to describe the association with moderate (VC width ≥ 0.5 cm) or severe (VC width ≥ 0.7 cm) TR, separately, using bivariate and stepwise multivariate logistic regression analysis. Results Forty-five of 100 patients showed device lead tricuspid valve leaflet interference. The septal leaflet was the most commonly affected (23 patients). On bivariate analysis, preimplantation VC width, right atrial size, tricuspid annular diameter, and lead-leaflet interference were significantly associated with postdevice TR. On multivariate analysis, preimplantation VC width and the presence of an interfering lead were independently associated with postdevice TR. Furthermore, the presence of an interfering lead was the only factor associated with TR worsening, increasing the likelihood of developing moderate or severe TR by 15- and 11-fold, respectively. Conclusion Lead-leaflet interference as seen on 3D echocardiography is associated with TR after device lead placement, suggesting that 3D echocardiography should be used to assess for lead interference in patients with significant TR. PMID:25129393
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Convelbo, Channing; Guetat, Pierre; Cambillau, Michèle; Allam, Bachir; Bruneval, Patrick; Lafont, Antoine; Zegdi, Rachid
2013-12-01
Leaflet injury has been documented to occur during the deployment of valved stents (VSs). The pathological aspects, however, of this injury are difficult to quantify. Conversely, the hydraulic conductance of a (pericardial) membrane may be easily determined. The impact of crimping and deployment of VS on this parameter was therefore investigated. Bovine pericardial square (25 × 25 mm) patches were placed within a pressure chamber and their hydraulic conductance was determined. The influence of the pressure gradient and tissue thickness on this parameter was analysed. Six balloon-expandable VS were constructed. The hydraulic conductance of their bovine pericardial leaflets was determined before and after VS crimping and deployment in four of them. Pericardial leaflets of non-crimped VS were used as controls. Hydraulic conductance increased insignificantly with the pressure level within the chamber: from 128 ± 26.9 ml/h/m(2)/mmHg at a pressure of 50 mmHg to 232.3 ± 51.9 ml/h/m(2)/mmHg at a pressure of 250 mmHg (P = 0.117). Hydraulic conductance was not correlated to pericardial thickness, for thickness measurements ranging from 0.34 to 0.76 mm. The hydraulic conductance of VS leaflets significantly increased immediately after crimping from 45.2 ± 7.6 to 667.9.0 ± 527.2 ml/h/m(2)/mmHg (P < 0.001). This increase was still observed 24 h after VS deployment. No change in hydraulic conductance occurred in the control group. The determination of the hydraulic conductance of pericardial patches was easy to perform, reproducible and not influenced by tissue thickness. The hydraulic conductance of pericardial leaflets dramatically increased after VS crimping and deployment. This parameter might be, in the future, a useful noninvasive tool in studying leaflet trauma.
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Finite element modeling of mitral leaflet tissue using a layered shell approximation
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
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Konishi, Takao; Funayama, Naohiro; Yamamoto, Tadashi; Hotta, Daisuke; Kikuchi, Kenjiro; Ohori, Katsumi; Nishihara, Hiroshi; Tanaka, Shinya
2016-11-22
A small mitral valve aneurysm (MVA) presenting as severe mitral regurgitation (MR) is uncommon. A 47-year-old man with a history of hypertension complained of exertional chest discomfort. A transthoracic echocardiogram (TTE) revealed the presence of MR and prolapse of the posterior leaflet. A 6-mm in diameter MVA, not clearly visualized by TTE, was detected on the posterior leaflet on a three-dimensional (3D) transesophageal echocardiography (TEE). The patient underwent uncomplicated triangular resection of P2 and mitral valve annuloplasty, and was discharged from postoperative rehabilitation, 2 weeks after the operation. Histopathology of the excised leaflet showed myxomatous changes without infective vegetation or signs of rheumatic heart disease. A small, isolated MVA is a cause of severe MR, which might be overlooked and, therefore, managed belatedly. 3D TEE was helpful in imaging its morphologic details.
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The death of distinctions: From 9/11 to Abu Ghraib.
Moon, John Ellis van Courtland
2004-09-01
War, the great simplifier, is the inevitable enemy of distinctions, especially when conflicts evoke survival fears, sounding echoes from humanity's environment of evolutionary adaptation. Throughout the twentieth century, attackers and targets grew more distant, weaponry grew more destructive, and distinctions -- between combatants and civilians, between legitimate and protected targets, between defensive and offensive strategies, between the innocent and the guilty -- faded. In the twenty-first century's first major conflict, "the war against terror," distinctions have faded still further, making nearly indistinguishable the frontier between preemption and prevention and between interrogation and torture. Proclaimed a "new type of war" in which old rules and customary safeguards would often be inapplicable, this conflict quickly came to be characterized by political embarrassment and operational scandal.
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Category Cued Recall Evokes a Generate-Recognize Retrieval Process
ERIC Educational Resources Information Center
Hunt, R. Reed; Smith, Rebekah E.; Toth, Jeffrey P.
2016-01-01
The experiments reported here were designed to replicate and extend McCabe, Roediger, and Karpicke's (2011) finding that retrieval in category cued recall involves both controlled and automatic processes. The extension entailed identifying whether distinctive encoding affected 1 or both of these 2 processes. The first experiment successfully…
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Lights … action: Comparison of trauma films for use in the trauma film paradigm.
Arnaudova, Inna; Hagenaars, Muriel A
2017-06-01
Affective films are often used in emotion research and negative films are frequently used as an analogue for trauma (trauma film paradigm). However, different films are used with possibly distinct consequences. We aimed to investigate specific effects of four negative films covering distinct themes (physical, sexual, traffic and food), and tested neutral and positive films with matching content. Self-reported emotional responses and heart rate during the films were examined (immediate responses) as well as intrusions of the films in the subsequent week (delayed responses). Within each theme, negative films were rated as more unpleasant than the positive and neutral counterparts. They also evoked more negative emotions and more intrusive memories. Across themes, the four negative films did not differ in terms of valence and arousal, but clearly differed on immediate (e.g., disgust, embarrassment, heart rate) and delayed (intrusions) effects. Thus, we urge researchers to carefully select negative films for their studies, as different films seem to evoke distinct emotional responses. In addition, using positive films within the same themes is recommended in order to control for effects of arousal. In general, the specific film material should be considered when comparing effects across studies. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Bones, Oliver; Plack, Christopher J
2015-03-04
When two musical notes with simple frequency ratios are played simultaneously, the resulting musical chord is pleasing and evokes a sense of resolution or "consonance". Complex frequency ratios, on the other hand, evoke feelings of tension or "dissonance". Consonance and dissonance form the basis of harmony, a central component of Western music. In earlier work, we provided evidence that consonance perception is based on neural temporal coding in the brainstem (Bones et al., 2014). Here, we show that for listeners with clinically normal hearing, aging is associated with a decline in both the perceptual distinction and the distinctiveness of the neural representations of different categories of two-note chords. Compared with younger listeners, older listeners rated consonant chords as less pleasant and dissonant chords as more pleasant. Older listeners also had less distinct neural representations of consonant and dissonant chords as measured using a Neural Consonance Index derived from the electrophysiological "frequency-following response." The results withstood a control for the effect of age on general affect, suggesting that different mechanisms are responsible for the perceived pleasantness of musical chords and affective voices and that, for listeners with clinically normal hearing, age-related differences in consonance perception are likely to be related to differences in neural temporal coding. Copyright © 2015 Bones and Plack.
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Plack, Christopher J.
2015-01-01
When two musical notes with simple frequency ratios are played simultaneously, the resulting musical chord is pleasing and evokes a sense of resolution or “consonance”. Complex frequency ratios, on the other hand, evoke feelings of tension or “dissonance”. Consonance and dissonance form the basis of harmony, a central component of Western music. In earlier work, we provided evidence that consonance perception is based on neural temporal coding in the brainstem (Bones et al., 2014). Here, we show that for listeners with clinically normal hearing, aging is associated with a decline in both the perceptual distinction and the distinctiveness of the neural representations of different categories of two-note chords. Compared with younger listeners, older listeners rated consonant chords as less pleasant and dissonant chords as more pleasant. Older listeners also had less distinct neural representations of consonant and dissonant chords as measured using a Neural Consonance Index derived from the electrophysiological “frequency-following response.” The results withstood a control for the effect of age on general affect, suggesting that different mechanisms are responsible for the perceived pleasantness of musical chords and affective voices and that, for listeners with clinically normal hearing, age-related differences in consonance perception are likely to be related to differences in neural temporal coding. PMID:25740534
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Brown, Paul; Dale, Nicholas
2002-01-01
As the release of ATP from neurons has only been directly studied in a few cases, we have used patch sniffing to examine ATP release from Xenopus spinal neurons. ATP release was detected following intracellular current injection to evoke spikes. However, spiking was not essential as both glutamate and NMDA could evoke release of ATP in the presence of TTX. Neither acetylcholine nor high K+ was effective at inducing ATP release in the presence of TTX. Although Cd2+ blocked glutamate-evoked release of ATP suggesting a dependence on Ca2+ entry, neither ω-conotoxin-GVIA nor nifedipine prevented ATP release. N-type and L-type channels are thus not essential for glutamate-evoked ATP release. That glutamate receptors can elicit release in the absence of spiking suggests a close physical relationship between these receptors, the Ca2+ channels and release sites. As the dependence of ATP release on the influx of Ca2+ through Ca2+ channel subtypes differs from that of synaptic transmitter release, ATP may be released from sites that are distinct from those of the principal transmitter. In addition to its role as a fast transmitter, ATP may thus be released as a consequence of the activation of excitatory glutamatergic synapses and act to signal information about activity patterns in the nervous system. PMID:11986374
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Cortical evoked potentials to an auditory illusion: binaural beats.
Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi
2009-08-01
To define brain activity corresponding to an auditory illusion of 3 and 6Hz binaural beats in 250Hz or 1000Hz base frequencies, and compare it to the sound onset response. Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000Hz to one ear and 3 or 6Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3Hz and 6Hz, in base frequencies of 250Hz and 1000Hz. Tones were 2000ms in duration and presented with approximately 1s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. All stimuli evoked tone-onset P(50), N(100) and P(200) components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P(50) had significantly different sources than the beats-evoked oscillations; and N(100) and P(200) sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp.
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Cortical Evoked Potentials to an Auditory Illusion: Binaural Beats
Pratt, Hillel; Starr, Arnold; Michalewski, Henry J.; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi
2009-01-01
Objective: To define brain activity corresponding to an auditory illusion of 3 and 6 Hz binaural beats in 250 Hz or 1,000 Hz base frequencies, and compare it to the sound onset response. Methods: Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000 Hz to one ear and 3 or 6 Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3 Hz and 6 Hz, in base frequencies of 250 Hz and 1000 Hz. Tones were 2,000 ms in duration and presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. Results: All stimuli evoked tone-onset P50, N100 and P200 components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P50 had significantly different sources than the beats-evoked oscillations; and N100 and P200 sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Conclusions: Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Significance: Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp. PMID:19616993
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Sherrid, Mark V; Kushner, Josef; Yang, Georgiana; Ro, Richard
2017-04-01
Three competing theories about the mechanism of mitral coaptation in normal subjects were evaluated by color Doppler and vector flow mapping (VFM): (1) beginning of ventricular (LV) ejection, (2) "breaking of the jet" of diastolic LV inflow, and (3) returning diastolic vortices impacting the leaflets on their LV surfaces. We analyzed 80 color Doppler frames and 320 VFM measurements. In all 20 normal subjects, coaptation occurred before LV ejection, 78±16 ms before onset. On color Doppler frames the larger anterior, and smaller posterior vortices circle back and, in all cases, strike the ventricular surfaces of the leaflets. On the first closing-begins frame, for the first time, vortex velocity normal to the ventricular surface of the anterior leaflet (AML) is greater than that in the mitral orifice, and the angle of attack of LV vortical flow onto the AML is twice as high as the angle of flow onto the valve in orifice. Thus, at the moment coaptation begins, vortical flow strikes the mitral leaflet with higher velocity, and higher angle of attack than orifice flow, and thus with greater force. According to the "breaking of the jet" theory, one would expect to see de novo LV flow perpendicular to the leaflets beginning after transmitral flow terminates. Instead, the returning continuous LV vortical flow that impacts the valve builds continuously after the P-wave. Late diastolic vortices strike the ventricular surfaces of the mitral leaflets and contribute to valve coaptation, permitted by concomitant decline in transmitral flow. © 2017, Wiley Periodicals, Inc.
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Aggarwal, Ankush; Sacks, Michael S
2016-08-01
Determining the biomechanical behavior of heart valve leaflet tissues in a noninvasive manner remains an important clinical goal. While advances in 3D imaging modalities have made in vivo valve geometric data available, optimal methods to exploit such information in order to obtain functional information remain to be established. Herein we present and evaluate a novel leaflet shape-based framework to estimate the biomechanical behavior of heart valves from surface deformations by exploiting tissue structure. We determined accuracy levels using an "ideal" in vitro dataset, in which the leaflet geometry, strains, mechanical behavior, and fibrous structure were known to a high level of precision. By utilizing a simplified structural model for the leaflet mechanical behavior, we were able to limit the number of parameters to be determined per leaflet to only two. This approach allowed us to dramatically reduce the computational time and easily visualize the cost function to guide the minimization process. We determined that the image resolution and the number of available imaging frames were important components in the accuracy of our framework. Furthermore, our results suggest that it is possible to detect differences in fiber structure using our framework, thus allowing an opportunity to diagnose asymptomatic valve diseases and begin treatment at their early stages. Lastly, we observed good agreement of the final resulting stress-strain response when an averaged fiber architecture was used. This suggests that population-averaged fiber structural data may be sufficient for the application of the present framework to in vivo studies, although clearly much work remains to extend the present approach to in vivo problems.
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X-ray CT and histological imaging of xylem vessels organization in Mimosa pudica.
Lee, Sang Joon; Song, Kahye; Kim, Hae Koo; Park, Joonghyuk
2013-11-01
Mimosa pudica has three distinct specialized organs, namely, pulvinus, secondary pulvinus, and pulvinule, which are respectively controlling the movements of petioles, leaflets, and pinna in response to external stimuli. Water flow is a key factor for such movements, but detailed studies on the organization of the vascular system for water transport in these organs have not been published yet. In this study, organizations of the xylem vessels and morphological features of the pulvinus, the secondary pulvinus, and the pulvinule were experimentally investigated by X-ray computed tomography and histological technique. Results showed that the xylem vessels were circularly distributed in the specialized motile organs and reorganized into distinct vascular bundles at the extremities. The number and the total cross-sectional area of the xylem vessels were increased inside the specialized motile organs. Morphological characteristics obtained in this study provided new insight to understand the functions of the vascular networks in the dynamic movements of M. pudica. Copyright © 2013 Wiley Periodicals, Inc.
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Physiotherapy Post Lumbar Discectomy: Prospective Feasibility and Pilot Randomised Controlled Trial
Rushton, Alison; Goodwin, Peter C.
2015-01-01
Objectives To evaluate: acceptability and feasibility of trial procedures; distribution of scores on the Roland Morris Disability Questionnaire (RMDQ, planned primary outcome); and efficient working of trial components. Design and Setting A feasibility and external pilot randomised controlled trial (ISRCTN33808269, assigned 10/12/2012) was conducted across 2 UK secondary care outpatient physiotherapy departments associated with regional spinal surgery centres. Participants Consecutive consenting patients aged >18 years; post primary, single level, lumbar discectomy. Interventions Participants were randomised to either 1:1 physiotherapy outpatient management including patient leaflet, or patient leaflet alone. Main Outcome Measures Blinded assessments were made at 4 weeks post surgery (baseline) and 12 weeks post baseline (proposed primary end point). Secondary outcomes included: Global Perceived Effect, back/leg pain, straight leg raise, return to work/function, quality of life, fear avoidance, range of movement, medication, re-operation. Results At discharge, 110 (44%) eligible patients gave consent to be contacted. 59 (54%) patients were recruited. Loss to follow up was 39% at 12 weeks, with one site contributing 83% losses. Mean (SD) RMDQ was 10.07 (5.58) leaflet and 10.52 (5.94) physiotherapy/leaflet at baseline; and 5.37 (4.91) leaflet and 5.53 (4.49) physiotherapy/leaflet at 12 weeks. 5.1% zero scores at 12 weeks illustrated no floor effect. Sensitivity to change was assessed at 12 weeks with mean (SD) change -4.53 (6.41), 95%CI -7.61 to -1.44 for leaflet; and -6.18 (5.59), 95%CI -9.01 to -3.30 for physiotherapy/leaflet. RMDQ mean difference (95%CI) between change from baseline to twelve weeks was 1.65(-2.46 to 5.75). Mean difference (95%CI) between groups at 12 weeks was -0.16 (-3.36 to 3.04). Participant adherence with treatment was good. No adverse events were reported. Conclusions Both interventions were acceptable, and it is promising that they both demonstrated a trend in reducing disability in this population. A randomised controlled trial, using a different trial design, is needed to ascertain the effectiveness of combining the interventions into a stepped care intervention and comparing to a no intervention arm. Findings will guide design changes for an adequately powered randomised controlled trial, using RMDQ as the primary outcome. Trial Registration ISRCTN registry 33808269 PMID:26562660
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Multiple P2Y receptor subtypes in the apical membranes of polarized epithelial cells
McAlroy, H L; Ahmed, S; Day, S M; Baines, D L; Wong, H Y; Yip, C Y; Ko, W H; Wilson, S M; Collett, A
2000-01-01
Apical ATP, ATP, UTP and UDP evoked transient increases in short circuit current (ISC, a direct measure of transepithelial ion transport) in confluent Caco-2 cells grown on permeable supports. These responses were mediated by a population of at least three pharmacologically distinct receptors. Experiments using cells grown on glass coverslips showed that ATP and UTP consistently increased intracellular free calcium ([Ca2+]i) whilst sensitivity to UDP was variable. Cross desensitization experiments suggested that the responses to UTP and ATP were mediated by a common receptor population. Messenger RNA transcripts corresponding to the P2Y2, P2Y4 and P2Y6 receptors genes were detected in cells grown on Transwell membranes by the reverse transcriptase–polymerase chain reaction. Identical results were obtained for cells grown on glass. Experiments in which ISC and [Ca2+]i were monitored simultaneously in cells on Transwell membranes, confirmed that apical ATP and UTP increased both parameters and showed that the UDP-evoked increase in ISC was accompanied by a [Ca2+]i-signal. Ionomycin consistently increased [Ca2+]i in such polarized cells but caused no discernible change in ISC. However, subsequent application of apical ATP or UTP evoked a small rise in ISC but no rise in [Ca2+]i. UDP evoked no such response. As well as evoking increases in [Ca2+]i, the ATP/UTP-sensitive receptors present in Caco-2 cells thus allow direct control over ion channels in the apical membrane. The UDP-sensitive receptors, however, appear to simply evoke a rise in [Ca2+]i. PMID:11139443
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Ajram, Laura; Begg, Malcolm; Slack, Robert; Cryan, Jenni; Hall, David; Hodgson, Simon; Ford, Alison; Barnes, Ashley; Swieboda, Dawid; Mousnier, Aurelie; Solari, Roberto
2014-01-01
The chemokine receptor CCR4 has at least two natural agonist ligands, MDC (CCL22) and TARC (CCL17) which bind to the same orthosteric site with a similar affinity. Both ligands are known to evoke chemotaxis of CCR4-bearing T cells and also elicit CCR4 receptor internalization. A series of small molecule allosteric antagonists have been described which displace the agonist ligand, and inhibit chemotaxis. The aim of this study was to determine which cellular coupling pathways are involved in internalization, and if antagonists binding to the CCR4 receptor could themselves evoke receptor internalization. CCL22 binding coupled CCR4 efficiently to β-arrestin and stimulated GTPγS binding however CCL17 did not couple to β-arrestin and only partially stimulated GTPγS binding. CCL22 potently induced internalization of almost all cell surface CCR4, while CCL17 showed only weak effects. We describe four small molecule antagonists that were demonstrated to bind to two distinct allosteric sites on the CCR4 receptor, and while both classes inhibited agonist ligand binding and chemotaxis, one of the allosteric sites also evoked receptor internalization. Furthermore, we also characterize an N-terminally truncated version of CCL22 which acts as a competitive antagonist at the orthosteric site, and surprisingly also evokes receptor internalization without demonstrating any agonist activity. Collectively this study demonstrates that orthosteric and allosteric antagonists of the CCR4 receptor are capable of evoking receptor internalization, providing a novel strategy for drug discovery against this class of target. PMID:24534492
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The inner side of T cell lipid rafts.
Gri, Giorgia; Molon, Barbara; Manes, Santos; Pozzan, Tullio; Viola, Antonella
2004-07-15
A key question in understanding the functional role of lipid rafts is whether lipid microdomains at the plasma membrane outer leaflet are coupled to lipid microdomains at the inner leaflet. By using a cyan-fluorescent protein (CFP) targeted to inner plasma membrane rafts of Jurkat T cells, we found that raft domains at the outer and inner leaflets are physically coupled and that this coupling requires cholesterol. Interestingly, TCR/CD3 cross-linking induces co-capping of the raft bilayer independently of cholesterol or signaling events, indicating that cholesterol-extracting drugs are unable to destroy TCR-lipid rafts interaction.
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Yunoki, Junji; Minato, Naoki; Katayama, Yuji; Sato, Hisashi
2009-01-01
We treated a 61-year-old woman with mitral stenosis caused by pannus formation after Duran ring annuloplasty. Pannus overgrowth on the ring with extension onto both leaflets narrowed the mitral orifice and severely restricted the mobility of the valve leaflets. Mitral valve replacement with a St. Jude Medical mechanical heart valve prosthesis was successfully performed, and the postoperative course was uneventful. Patients undergoing Duran ring annuloplasty should be followed up with the consideration of possible mitral stenosis caused by pannus extension, as the cause for pannus formation remains unclear.
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Premeasured Chordal Loops for Mitral Valve Repair.
Gillinov, Marc; Quinn, Reed; Kerendi, Faraz; Gaudiani, Vince; Shemin, Richard; Barnhart, Glenn; Raines, Edward; Gerdisch, Marc W; Banbury, Michael
2016-09-01
Premeasured expanded polytetrafluoroethylene chordal loops with integrated sutures for attachment to the papillary muscle and leaflet edges facilitate correction of mitral valve prolapse. Configured as a group of 3 loops (length range 12 to 24 mm), the loops are attached to a pledget that is passed through the papillary muscle and tied. Each of the loops has 2 sutures with attached needles; these needles are passed through the free edge of the leaflet and then the sutures are tied to each other, securing the chordal loop to the leaflet. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
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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.
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A descriptive study of the readability of patient information leaflets designed by nurses.
Mumford, M E
1997-11-01
Written patient information materials can be valuable communication tools for teaching and reinforcing the verbal message, especially in the present climate of today's health service where patients are in hospital for such short times. They are only useful if the patient is able to read and understand them, otherwise they become an expensive waste of resources. Various studies have shown that many healthcare information leaflets are written at university or postgraduate level and would cause problems with understanding for many people reading them. This study set out to examine the readability of nurse-designed written information leaflets using the Flesch Reading Ease score and the FOG and SMOG readability formulae. This descriptive study used a sample of 24 leaflets designed by trained nurses in a large teaching hospital. The results produced a mean grade of 11.3 with a range of 8.9 to 14.8. This was similar to the results of other studies and meant that patients may have difficulty comprehending the information. It would appear that little progress has been made in 40 years in this area and potential reasons are discussed. Advantages and disadvantages of readability formulae and other guidelines available for developing information leaflets are explored. Recommendations for further research are made.
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Bernardini, C; Ambrogi, V; Fardella, G; Perioli, L; Grandolini, G
2001-05-01
This paper displays the results of the second part of a survey about patient information and the use of the patient package leaflet. The aim of this research is to investigate the consumers' attitude towards written information. As the formal aspects of the written message are very important in communication, we prepared a questionnaire in order to evaluate the attitude of patients towards some typographical modifications. Patients were invited to give indications about which colours could be used in the different paragraphs of the package leaflet and which print size could be easily read. All people interviewed were asked to choose a colour, from six proposed by us, to be used for 'therapeutic indications', 'side effects', 'how to use', 'paediatric use', 'contraindications', 'use in pregnancy' and 'warnings'. Clear suggestions for the choice of colours for therapeutic indications, side effects and contraindications arose from the survey. In the other cases there was no uniformity of answers. All people complained that the print size used in the package leaflet is too small and suggested 10 and 11 points Didot. Finally, from the survey it emerged that people would appreciate a more detailed package leaflet but information should be given in a schematic and concise way. Copyright 2001 Academic Press.
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Yu, Jianbin; Ge, Liangfa; Wang, Hongliang; Berbel, Ana; Liu, Yu; Chen, Yuhui; Li, Guangming; Tadege, Million; Wen, Jiangqi; Cosson, Viviane; Mysore, Kirankumar S.; Ratet, Pascal; Madueño, Francisco; Bai, Guihua; Chen, Rujin
2010-01-01
Plant leaves are diverse in their morphology, reflecting to a large degree the plant diversity in the natural environment. How different leaf morphology is determined is not yet understood. The leguminous plant Medicago truncatula exhibits dissected leaves with three leaflets at the tip. We show that development of the trifoliate leaves is determined by the Cys(2)His(2) zinc finger transcription factor PALM1. Loss-of-function mutants of PALM1 develop dissected leaves with five leaflets clustered at the tip. We demonstrate that PALM1 binds a specific promoter sequence and down-regulates the expression of the M. truncatula LEAFY/UNIFOLIATA orthologue SINGLE LEAFLET1 (SGL1), encoding an indeterminacy factor necessary for leaflet initiation. Our data indicate that SGL1 is required for leaflet proliferation in the palm1 mutant. Interestingly, ectopic expression of PALM1 effectively suppresses the lobed leaf phenotype from overexpression of a class 1 KNOTTED1-like homeobox protein in Arabidopsis plants. Taken together, our results show that PALM1 acts as a determinacy factor, regulates the spatial-temporal expression of SGL1 during leaf morphogenesis and together with the LEAFY/UNIFOLIATA orthologue plays an important role in orchestrating the compound leaf morphology in M. truncatula. PMID:20498057
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Rim, Yonghoon; Laing, Susan T.; McPherson, David D.; Kim, Hyunggun
2013-01-01
Mitral valve repair using expanded polytetrafluoroethylene (ePTFE) sutures is an established and preferred interventional method to resolve the complex pathophysiologic problems associated with chordal rupture. We developed a novel computational evaluation protocol to determine the effect of the artificial sutures on restoring mitral valve function following valve repair. A virtual mitral valve was created using three-dimensional echocardiographic data in a patient with ruptured mitral chordae tendineae. Virtual repairs were designed by adding artificial sutures between the papillary muscles and the posterior leaflet where the native chordae were ruptured. Dynamic finite element simulations were performed to evaluate pre- and post-repair mitral valve function. Abnormal posterior leaflet prolapse and mitral regurgitation was clearly demonstrated in the mitral valve with ruptured chordae. Following virtual repair to reconstruct ruptured chordae, the severity of the posterior leaflet prolapse decreased and stress concentration was markedly reduced both in the leaflet tissue and the intact native chordae. Complete leaflet coaptation was restored when four or six sutures were utilized. Computational simulations provided quantitative information of functional improvement following mitral valve repair. This novel simulation strategy may provide a powerful tool for evaluation and prediction of interventional treatment for ruptured mitral chordae tendineae. PMID:24072489
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Della Santina, Luca; Inman, Denise M; Lupien, Caroline B; Horner, Philip J; Wong, Rachel O L
2013-10-30
Intraocular pressure (IOP) elevation is a principal risk factor for glaucoma. Using a microbead injection technique to chronically raise IOP for 15 or 30 d in mice, we identified the early changes in visual response properties of different types of retinal ganglion cells (RGCs) and correlated these changes with neuronal morphology before cell death. Microbead-injected eyes showed reduced optokinetic tracking as well as cell death. In such eyes, multielectrode array recordings revealed that four RGC types show diverse alterations in their light responses upon IOP elevation. OFF-transient RGCs exhibited a more rapid decline in both structural and functional organizations compared with other RGCs. In contrast, although the light-evoked responses of OFF-sustained RGCs were perturbed, the dendritic arbor of this cell type remained intact. ON-transient and ON-sustained RGCs had normal functional receptive field sizes but their spontaneous and light-evoked firing rates were reduced. ON- and OFF-sustained RGCs lost excitatory synapses across an otherwise structurally normal dendritic arbor. Together, our observations indicate that there are changes in spontaneous activity and light-evoked responses in RGCs before detectable dendritic loss. However, when dendrites retract, we found corresponding changes in receptive field center size. Importantly, the effects of IOP elevation are not uniformly manifested in the structure and function of diverse RGC populations, nor are distinct RGC types perturbed within the same time-frame by such a challenge.
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24 CFR 245.115 - Protected activities.
Code of Federal Regulations, 2010 CFR
2010-04-01
... operation of a tenant organization: (1) Distributing leaflets in lobby areas; (2) Placing leaflets at or... management representatives. In order to preserve the independence of tenant organizations, management... discuss a specific issue or issues; and (9) Formulating responses to owner's requests for: (i) Rent...
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Parato, Vito Maurizio; Masia, Stefano Lucio
2018-01-01
We present a case series of two adult patients with almost complete absence of the posterior mitral valve leaflet and who are asymptomatic or mildly symptomatic, with two different degrees of mitral regurgitation.
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Seidelmann, Katrin; Melzer, Björn; Speck, Thomas
2012-11-01
Monkey's comb (Amphilophium crucigerum) is a widely spread neotropical leaf climber that develops attachment pads for anchorage. A single complex leaf of the species comprises a basal pair of foliate, assimilating leaflets and apical, attaching leaflet tendrils. This study aims to analyze these leaves and their ontogenetic development for a better understanding of the attachment process, the form-structure-function relationships involved, and the overall maturation of the leaves. Thorough morphometrical, morphological, and anatomical analyses incorporated high-resolution microscopy, various staining techniques, SEM, and photographic recordings over the entire ontogenetic course of leaf development. The foliate, assimilating leaflets and the anchorage of the more apical leaflet tendrils acted independently of each other. Attachment was achieved by coiling of the leaflet tendrils and/or development of attachment pads at the tendril apices that grow opportunistically into gaps and fissures of the substrate. In contact zones with the substrate, the cells of the pads differentiate into a vessel element-like tissue. During the entire attachment process of the plant, no glue was excreted. The complex leaves of monkey's comb are highly differentiated organs with specialized leaf parts whose functions-photosynthesis or attachment-work independently of each other. The function of attachment includes coiling and maturation process of the leaflet tendrils and the formation of attachment pads, resulting in a biomechanically sound and persistent anchorage of the plant without the need of glue excretion. This kind of glue-less attachment is not only of interest in the framework of analyzing the functional variety of attachment structures evolved in climbing plants, but also for the development of innovative biomimetic attachment structures for manifold technical applications.
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Aquila, Iolanda; González, Ariana; Fernández-Golfín, Covadonga; Rincón, Luis Miguel; Casas, Eduardo; García, Ana; Hinojar, Rocio; Jiménez-Nacher, José Julio; Zamorano, José Luis
2016-05-17
3D transesophageal echocardiography (TEE) is superior to 2D TEE in quantitative anatomic evaluation of the mitral valve (MV) but it shows limitations regarding automatic quantification. Here, we tested the inter-/intra-observer reproducibility of a novel full-automated software in the evaluation of MV anatomy compared to manual 3D assessment. Thirty-six out of 61 screened patients referred to our Cardiac Imaging Unit for TEE were retrospectively included. 3D TEE analysis was performed both manually and with the automated software by two independent operators. Mitral annular area, intercommissural distance, anterior leaflet length and posterior leaflet length were assessed. A significant correlation between both methods was found for all variables: intercommissural diameter (r = 0.84, p < 0.01), mitral annular area (r = 0.94, p > 0, 01), anterior leaflet length (r = 0.83, p < 0.01) and posterior leaflet length (r = 0.67, p < 0.01). Interobserver variability assessed by the intraclass correlation coefficient was superior for the automatic software: intercommisural distance 0.997 vs. 0.76; mitral annular area 0.957 vs. 0.858; anterior leaflet length 0.963 vs. 0.734 and posterior leaflet length 0.936 vs. 0.838. Intraobserver variability was good for both methods with a better level of agreement with the automatic software. The novel 3D automated software is reproducible in MV anatomy assessment. The incorporation of this new tool in clinical MV assessment may improve patient selection and outcomes for MV interventions as well as patient diagnosis and prognosis stratification. Yet, high-quality 3D images are indispensable.
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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.
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Readability of medicinal package leaflets: a systematic review.
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.
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Toma, Milan; Einstein, Daniel R.; Bloodworth, Charles H.; Cochran, Richard P.; Yoganathan, Ajit P.; Kunzelman, Karyn S.
2016-01-01
Over the years, three-dimensional models of the mitral valve have generally been organized around a simplified anatomy. Leaflets have been typically modeled as membranes, tethered to discrete chordae typically modeled as one-dimensional, non-linear cables. Yet, recent, high-resolution medical images have revealed that there is no clear boundary between the chordae and the leaflets. In fact, the mitral valve has been revealed to be more of a webbed structure whose architecture is continuous with the chordae and their extensions into the leaflets. Such detailed images can serve as the basis of anatomically accurate, subject-specific models, wherein the entire valve is modeled with solid elements that more faithfully represent the chordae, the leaflets, and the transition between the two. These models have the potential to enhance our understanding of mitral valve mechanics, and to re-examine the role of the mitral valve chordae, which heretofore have been considered to be “invisible” to the fluid and to be of secondary importance to the leaflets. However, these new models also require a rethinking of modeling assumptions. In this study, we examine the conventional practice of loading the leaflets only and not the chordae in order to study the structural response of the mitral valve apparatus. Specifically, we demonstrate that fully resolved 3D models of the mitral valve require a fluid-structure interaction analysis to correctly load the valve even in the case of quasi-static mechanics. While a fluid-structure interaction mode is still more computationally expensive than a structural-only model, we also show that advances in GPU computing have made such models tractable. PMID:27342229
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Toma, Milan; Einstein, Daniel R; Bloodworth, Charles H; Cochran, Richard P; Yoganathan, Ajit P; Kunzelman, Karyn S
2017-04-01
Over the years, three-dimensional models of the mitral valve have generally been organized around a simplified anatomy. Leaflets have been typically modeled as membranes, tethered to discrete chordae typically modeled as one-dimensional, non-linear cables. Yet, recent, high-resolution medical images have revealed that there is no clear boundary between the chordae and the leaflets. In fact, the mitral valve has been revealed to be more of a webbed structure whose architecture is continuous with the chordae and their extensions into the leaflets. Such detailed images can serve as the basis of anatomically accurate, subject-specific models, wherein the entire valve is modeled with solid elements that more faithfully represent the chordae, the leaflets, and the transition between the two. These models have the potential to enhance our understanding of mitral valve mechanics and to re-examine the role of the mitral valve chordae, which heretofore have been considered to be 'invisible' to the fluid and to be of secondary importance to the leaflets. However, these new models also require a rethinking of modeling assumptions. In this study, we examine the conventional practice of loading the leaflets only and not the chordae in order to study the structural response of the mitral valve apparatus. Specifically, we demonstrate that fully resolved 3D models of the mitral valve require a fluid-structure interaction analysis to correctly load the valve even in the case of quasi-static mechanics. While a fluid-structure interaction mode is still more computationally expensive than a structural-only model, we also show that advances in GPU computing have made such models tractable. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
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Weltert, Luca; de Tullio, Marco D.; Afferrante, Luciano; Salica, Andrea; Scaffa, Raffaele; Maselli, Daniele; Verzicco, Roberto; De Paulis, Ruggero
2013-01-01
OBJECTIVES In the belief that stress is the main determinant of leaflet quality deterioration, we sought to evaluate the effect of annular and/or sino-tubular junction dilatation on leaflet stress. A finite element computer-assisted stress analysis was used to model four different anatomic conditions and analyse the consequent stress pattern on the aortic valve. METHODS Theoretical models of four aortic root configurations (normal, with dilated annulus, with loss of sino-tubular junction and with both dilatation simultaneously) were created with computer-aided design technique. The pattern of stress and strain was then analysed by means of finite elements analysis, when a uniform pressure of 100 mmHg was applied to the model. Analysis produced von Mises charts (colour-coded, computational, three-dimensional stress-pattern graphics) and bidimensional plots of compared stress on arc-linear line, which allowed direct comparison of stress in the four different conditions. RESULTS Stresses both on the free margin and on the ‘belly’ of the leaflet rose from 0.28 MPa (normal conditions) to 0.32 MPa (+14%) in case of isolated dilatation of the sino-tubular junction, while increased to 0.42 MPa (+67%) in case of isolated annular dilatation, with no substantial difference whether sino-tubular junction dilatation was present or not. CONCLUSIONS Annular dilatation is the key element determining an increased stress on aortic leaflets independently from an associated sino-tubular junction dilatation. The presence of annular dilatation associated with root aneurysm greatly decreases the chance of performing a valve sparing procedure without the need for additional manoeuvres on leaflet tissue. This information may lead to a refinement in the optimal surgical strategy. PMID:23536020
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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
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Posterior leaflet preservation during mitral valve replacement for rheumatic mitral stenosis.
Djukić, P L; Obrenović-Kirćanski, B B; Vranes, M R; Kocica, M J; Mikić, A Dj; Velinović, M M; Kacar, S M; Kovacević, N S; Parapid, B J
2006-01-01
Mitral valve replacement with posterior leaflet preservation was shown beneficial for postoperative left vetricular (LV) performance in patients with mitral regurgitation. Some authors find it beneficial even for the long term LV function. We investigated a long term effect of this technique in patients with rheumatic mitral stenosis. We studied 20 patents with mitral valve replacement due to rheumatic mitral stenosis, in the period from January 1988 to December 1989. In group A (10 patients) both leaflets and coresponding chordal excision was performed, while in group B (10 patients) the posterior leaflet was preserved. In all patients a Carbomedics valve was inserted. We compared clinical pre and postoperative status, as well as hemodynamic characteristics of the valve and left ventricle in both groups. Control echocardiographyc analysis included: maximal (PG) and mean (MG) gradients; effective valve area (AREA); telediastolic (TDV) and telesystolic (TSV) LV volume; stroke volume (SV); ejection fraction (EF); fractional shortening (FS) and segmental LV motion. The mean size of inserted valve was 26.6 in group A and 27.2 in group B. Hemodynamic data: PG (10.12 vs 11.1); MG (3.57 vs 3.87); AREA (2.35 vs 2.30); TDV 126.0 vs 114.5); TSV (42.2 vs 36.62); SV (83.7 vs 77.75); EF (63.66 vs 67.12); FS (32.66 vs 38.25). Diaphragmal segmental hypokinesis was evident in one patient from group A and in two patients from group B. In patients with rheumatic stenosis, posterior leaflet preservation did not have increased beneficial effect on left ventricular performance during long-term follow-up. An adequate posterior leaflet preservation does not change hemodynamic valvular characteristics even after long-term follow-up.
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ERIC Educational Resources Information Center
Kindt, Karlijn C. M.; Kleinjan, Marloes; Janssens, Jan M. A. M.; Scholte, Ron H. J.
2016-01-01
As restructuring a negative cognitive style is a central skill taught in many depression prevention programs, we tested whether a universal prevention program evoked a change in negative cognitive style in adolescents. In addition, we examined distinct developmental trajectories of negative cognitive styles and assessed whether research condition…
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Modeling discrete and continuous entities with fractions and decimals.
Rapp, Monica; Bassok, Miriam; DeWolf, Melissa; Holyoak, Keith J
2015-03-01
When people use mathematics to model real-life situations, their use of mathematical expressions is often mediated by semantic alignment (Bassok, Chase, & Martin, 1998): The entities in a problem situation evoke semantic relations (e.g., tulips and vases evoke the functionally asymmetric "contain" relation), which people align with analogous mathematical relations (e.g., the noncommutative division operation, tulips/vases). Here we investigate the possibility that semantic alignment is also involved in the comprehension and use of rational numbers (fractions and decimals). A textbook analysis and results from two experiments revealed that both mathematic educators and college students tend to align the discreteness versus continuity of the entities in word problems (e.g., marbles vs. distance) with distinct symbolic representations of rational numbers--fractions versus decimals, respectively. In addition, fractions and decimals tend to be used with nonmetric units and metric units, respectively. We discuss the importance of the ontological distinction between continuous and discrete entities to mathematical cognition, the role of symbolic notations, and possible implications of our findings for the teaching of rational numbers. PsycINFO Database Record (c) 2015 APA, all rights reserved.
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Xu, Wei; Morishita, Wade; Buckmaster, Paul S; Pang, Zhiping P; Malenka, Robert C; Südhof, Thomas C
2012-03-08
Neurons encode information by firing spikes in isolation or bursts and propagate information by spike-triggered neurotransmitter release that initiates synaptic transmission. Isolated spikes trigger neurotransmitter release unreliably but with high temporal precision. In contrast, bursts of spikes trigger neurotransmission reliably (i.e., boost transmission fidelity), but the resulting synaptic responses are temporally imprecise. However, the relative physiological importance of different spike-firing modes remains unclear. Here, we show that knockdown of synaptotagmin-1, the major Ca(2+) sensor for neurotransmitter release, abrogated neurotransmission evoked by isolated spikes but only delayed, without abolishing, neurotransmission evoked by bursts of spikes. Nevertheless, knockdown of synaptotagmin-1 in the hippocampal CA1 region did not impede acquisition of recent contextual fear memories, although it did impair the precision of such memories. In contrast, knockdown of synaptotagmin-1 in the prefrontal cortex impaired all remote fear memories. These results indicate that different brain circuits and types of memory employ distinct spike-coding schemes to encode and transmit information. Copyright © 2012 Elsevier Inc. All rights reserved.
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Multiphoton microscopy of ECM proteins in baboon aortic leaflet
NASA Astrophysics Data System (ADS)
Gonzalez, Mariacarla; Saytashev, Ilyas; Luna, Camila; Gonzalez, Brittany; Pinero, Alejandro; Perez, Manuel; Ramaswamy, Sharan; Ramella-Roman, Jessica
2018-02-01
The extracellular matrix (ECM) plays crucial role in defining mechanical properties of a heart valve yet the mechanobiological role of the ECM proteins - collagen and elastin - in living heart valve leaflets is still poorly understood. In this study, non-linear microscopy was used to obtain three dimensional images of collagen and elastin arrangement in aortic leaflets under combined steady flow (850 ml/min) and cyclic flexure (1 Hz) mechanical (dynamic) training. A novel bioreactor capable of mimicking the flow conditions in a living heart was used in this study and was optimized for microscopic imagery. A custom made non-linear microscope was used in this study to provide Second Harmonic Generation (SHG) imaging of collagen arrangement and two-photon imaging of elastin. Two control and three trained leaflet samples from static and dynamic tissue culture were imaged to observe protein changes in the tissue for a period of seven days. Dynamic training led to a decrease in alignment index of the protein fibers compared to the static treatment.
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Simulation of Blood flow in Different Configurations Design of Bi-leaflet Mechanical Heart Valve
NASA Astrophysics Data System (ADS)
Hafizah Mokhtar, N.; Abas, Aizat
2018-05-01
In this work, two different designs of artificial heart valve were devised and then compared by considering the thrombosis, wear and valve orifice to anatomical orifice ratio of each mechanical heart valve. These different design configurations of bi-leaflet mechanical heart valves model are created through the use of Computer-aided design (CAD) modelling and simulated using Computational fluid dynamic (CFD) software. Design 1 is based on existing conventional bi-leaflet valve and design 2 based on modified bi-leaflet respectively. The flow pattern, velocity, vorticity and stress analysis have been done to justify the best design. Based on results, both of the designs show a Doppler velocity index of less than the allowable standard of 2.2 which is safe to be used as replacement of the human heart valve. However, design 2 shows that it has a lower possibility of cavitation issue which will lead to lower thrombosis and provide good central flow area of blood as compared to design 1.
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[A philosophical information leaflet to accompany a DSM classification].
Kraaijenbrink, J; Kuipers, T; van der Laan, B; Kremer, S
2016-01-01
The introduction of the dsm-5 has re-ignited discussion about the classification of mental disorders. The public may have misconceptions with regard to the nature of the information contained in a dsm-classification. To bring about a conceptual switch so that the professional user of a classification sees it as an aid to diagnosis rather than as a definition of a problem or illness. We devised a 'thought experiment' to serve as a support for dsm classifications. The 'thought experiment' led us to devise a medicine package containing a 'philosophical' information leaflet. This 'thought-experiment', the information leaflet and the medicine package were presented to both students and trainee doctors at the ucp in Groningen and to clinicians at the fpc dr. S. van Mesdag Clinic. Students and trainee doctors were able to make the desired conceptual switch as a result of 'the thought experiment' and with the help they received from the medicine packaging containing the 'philosophical' information leaflet.
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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.
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Forman, M B; Phelan, B K; Robertson, R M; Virmani, R
1985-02-01
Two-dimensional echocardiographic findings in porcine valve dysfunction were compared with pathologic findings in 10 patients (12 valves). Three specific echocardiographic findings were identified in patients with regurgitant lesions: prolapse, fracture and flail leaflets. Prolapse was associated pathologically with thinning of the leaflets, longitudinal tears close to the ring margin and acid mucopolysaccharide accumulation. Valve fracture was seen with and without prolapse and was accompanied pathologically by small pinpoint perforations or tears of the leaflet. A flail leaflet was seen with a linear tear of the free margin and was associated with calcific deposits. Mild degrees of fracture seen pathologically were missed on the echocardiographic study in five patients. Thickening or calcification, when present in moderate or severe amounts, was correctly identified by echocardiography. When all abnormal features were considered collectively, two-dimensional echocardiography correctly identified at least one of them in all patients. Therefore, two-dimensional echocardiography may prove useful in assessing the source of valvular regurgitation in patients with bioprosthetic valves.
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Yokoyama, Satoko; Kanemoto, Isamu; Mihara, Kippei; Ando, Takanori; Kawase, Koudai; Sahashi, Yasuaki; Iguchi, Kazuhito
2017-01-01
Mitral valve plasty (MVP) is preferred over mitral valve replacement (MVR) for mitral regurgitation in humans because of its favorable effect on quality of life. In small dogs, it is difficult to repair multiple lesions in both leaflets using MVP. Herein, we report a case of severe mitral regurgitation caused by multiple severe lesions in the posterior leaflet (PL) in a mixed Chihuahua. Initially, we had planned MVR with an artificial valve. However, MVP combined with artificial chordal reconstruction of both leaflets, semicircular suture annuloplasty, and valvuloplasty using a newly devised direct scallop suture for the PL was attempted in this dog. The dog recovered well and showed no adverse cardiac signs, surviving two major operations. The dog died 4 years and 10 months after the MVP due to non-cardiovascular disease. Our additional technique of using a direct scallop suture seemed useful for PL repair involving multiple scallops in a small dog. PMID:29201662
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Bar-Kochva, Irit
2011-01-01
Orthographies range from shallow orthographies with transparent grapheme-phoneme relations, to deep orthographies, in which these relations are opaque. Two forms of script transcribe the Hebrew language: the shallow pointed script (with diacritics) and the deep unpointed script (without diacritics). This study was set out to examine whether the reading of these scripts evokes distinct brain activity. Preliminary results indicate distinct Event-related-potentials (ERPs). As an equivalent finding was absent when ERPs of non-orthographic stimuli with and without meaningless diacritics were compared, the results imply that print-specific aspects of processing account for the distinct activity elicited by the pointed and unpointed scripts.
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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 individually on the TEHV development, we designed a simple and novel stretch-flexure bioreactor in which samples were subjected to well-defined stimulations with a controlled strain-rate. The stretch and flexure was found to accelerate and increase tissue formation on the microfabricated PGS scaffolds cultivated in the bioreactors.
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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
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Intermonolayer Friction and Surface Shear Viscosity of Lipid Bilayer Membranes
den Otter, W. K.; Shkulipa, S. A.
2007-01-01
The flow behavior of lipid bilayer membranes is characterized by a surface viscosity for in-plane shear deformations, and an intermonolayer friction coefficient for slip between the two leaflets of the bilayer. Both properties have been studied for a variety of coarse-grained double-tailed model lipids, using equilibrium and nonequilibrium molecular dynamics simulations. For lipids with two identical tails, the surface shear viscosity rises rapidly with tail length, while the intermonolayer friction coefficient is less sensitive to the tail length. Interdigitation of lipid tails across the bilayer midsurface, as observed for lipids with two distinct tails, strongly enhances the intermonolayer friction coefficient, but hardly affects the surface shear viscosity. The simulation results are compared against the available experimental data. PMID:17468168
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Parato, Vito Maurizio; Masia, Stefano Lucio
2018-01-01
We present a case series of two adult patients with almost complete absence of the posterior mitral valve leaflet and who are asymptomatic or mildly symptomatic, with two different degrees of mitral regurgitation. PMID:29629259
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NASA Astrophysics Data System (ADS)
Davis, T. S.; Parker, R. A.; House, P. A.; Bagley, E.; Wendelken, S.; Normann, R. A.; Greger, B.
2012-12-01
Objective. It has been hypothesized that a vision prosthesis capable of evoking useful visual percepts can be based upon electrically stimulating the primary visual cortex (V1) of a blind human subject via penetrating microelectrode arrays. As a continuation of earlier work, we examined several spatial and temporal characteristics of V1 microstimulation. Approach. An array of 100 penetrating microelectrodes was chronically implanted in V1 of a behaving macaque monkey. Microstimulation thresholds were measured using a two-alternative forced choice detection task. Relative locations of electrically-evoked percepts were measured using a memory saccade-to-target task. Main results. The principal finding was that two years after implantation we were able to evoke behavioural responses to electric stimulation across the spatial extent of the array using groups of contiguous electrodes. Consistent responses to stimulation were evoked at an average threshold current per electrode of 204 ± 49 µA (mean ± std) for groups of four electrodes and 91 ± 25 µA for groups of nine electrodes. Saccades to electrically-evoked percepts using groups of nine electrodes showed that the animal could discriminate spatially distinct percepts with groups having an average separation of 1.6 ± 0.3 mm (mean ± std) in cortex and 1.0° ± 0.2° in visual space. Significance. These results demonstrate chronic perceptual functionality and provide evidence for the feasibility of a cortically-based vision prosthesis for the blind using penetrating microelectrodes.
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2016-01-01
Abstract We investigated whether dorsal (DR) and ventral root (VR) stimulus trains engage common postsynaptic components to activate the central pattern generator (CPG) for locomotion in the neonatal mouse spinal cord. VR stimulation did not activate the first order interneurons mediating the activation of the locomotor CPG by sacrocaudal afferent stimulation. Simultaneous stimulation of adjacent dorsal or ventral root pairs, subthreshold for evoking locomotor-like activity, did not summate to activate the CPG. This suggests that locomotor-like activity is triggered when a critical class of efferent or afferent axons is stimulated and does not depend on the number of stimulated axons or activated postsynaptic neurons. DR- and VR-evoked episodes exhibited differences in the coupling between VR pairs. In DR-evoked episodes, the coupling between the ipsilateral and contralateral flexor/extensor roots was similar and stronger than the bilateral extensor roots. In VR-evoked episodes, ipsilateral flexor/extensor coupling was stronger than both the contralateral flexor/extensor and the bilateral extensor coupling. For both types of stimulation, the coupling was greatest between the bilateral L1/L2 flexor-dominated roots. This indicates that the recruitment and/or the firing pattern of motoneurons differed in DR and VR-evoked episodes. However, the DR and VR trains do not appear to activate distinct CPGs because trains of DR and VR stimuli at frequencies too low to evoke locomotor-like activity did so when they were interleaved. These results indicate that the excitatory actions of VR stimulation converge onto the CPG through an unknown pathway that is not captured by current models of the locomotor CPG. PMID:27419215
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Tang, Wannan; Szokol, Karolina; Jensen, Vidar; Enger, Rune; Trivedi, Chintan A; Hvalby, Øivind; Helm, P Johannes; Looger, Loren L; Sprengel, Rolf; Nagelhus, Erlend A
2015-02-18
To date, it has been difficult to reveal physiological Ca(2+) events occurring within the fine astrocytic processes of mature animals. The objective of the study was to explore whether neuronal activity evokes astrocytic Ca(2+) signals at glutamatergic synapses of adult mice. We stimulated the Schaffer collateral/commissural fibers in acute hippocampal slices from adult mice transduced with the genetically encoded Ca(2+) indicator GCaMP5E driven by the glial fibrillary acidic protein promoter. Two-photon imaging revealed global stimulation-evoked astrocytic Ca(2+) signals with distinct latencies, rise rates, and amplitudes in fine processes and somata. Specifically, the Ca(2+) signals in the processes were faster and of higher amplitude than those in the somata. A combination of P2 purinergic and group I/II metabotropic glutamate receptor (mGluR) antagonists reduced the amplitude of the Ca(2+) transients by 30-40% in both astrocytic compartments. Blockage of the mGluRs alone only modestly reduced the magnitude of the stimulation-evoked Ca(2+) signals in processes and failed to affect the somatic Ca(2+) response. Local application of group I or I/II mGluR agonists or adenosine triphosphate (ATP) elicited global astrocytic Ca(2+) signals that mimicked the stimulation-evoked astrocytic Ca(2+) responses. We conclude that stimulation-evoked Ca(2+) signals in astrocytic processes at CA3-CA1 synapses of adult mice (1) differ from those in astrocytic somata and (2) are modulated by glutamate and ATP. Copyright © 2015 the authors 0270-6474/15/353016-06$15.00/0.
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Abbasi, Mostafa; Barakat, Mohammed S; Vahidkhah, Koohyar; Azadani, Ali N
2016-09-01
Computational modeling has an important role in design and assessment of medical devices. In computational simulations, considering accurate constitutive models is of the utmost importance to capture mechanical response of soft tissue and biomedical materials under physiological loading conditions. Lack of comprehensive three-dimensional constitutive models for soft tissue limits the effectiveness of computational modeling in research and development of medical devices. The aim of this study was to use inverse finite element (FE) analysis to determine three-dimensional mechanical properties of bovine pericardial leaflets of a surgical bioprosthesis under dynamic loading condition. Using inverse parameter estimation, 3D anisotropic Fung model parameters were estimated for the leaflets. The FE simulations were validated using experimental in-vitro measurements, and the impact of different constitutive material models was investigated on leaflet stress distribution. The results of this study showed that the anisotropic Fung model accurately simulated the leaflet deformation and coaptation during valve opening and closing. During systole, the peak stress reached to 3.17MPa at the leaflet boundary while during diastole high stress regions were primarily observed in the commissures with the peak stress of 1.17MPa. In addition, the Rayleigh damping coefficient that was introduced to FE simulations to simulate viscous damping effects of surrounding fluid was determined. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Caring: Information for Family Day-Care Providers.
ERIC Educational Resources Information Center
California Univ., Berkeley. Cooperative Extension Service.
This series of leaflets provides information for family day care providers on nine topics. Age differences and developmental stages are emphasized. The first topic concerns ways to help young children get along with others. Self-esteem is emphasized, and methods for helping children develop self-esteem are listed. The second leaflet discusses…
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[SAFE: Making Your Children Safer on Public Playgrounds.
ERIC Educational Resources Information Center
Thompson, Donna; Hudson, Susan D.
This collection of nine leaflets from the National Program for Playground Safety addresses the active role parents and other adults should take in ensuring playground safety for children. Four leaflets, each focusing on a topic related to a letter in the word "safe," provide suggestions to ensure playground safety. Leaflet…
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Nuclear Energy and the Environment.
ERIC Educational Resources Information Center
International Atomic Energy Agency, Vienna (Austria).
"Nuclear Energy and the Environment" is a pocket folder of removable leaflets concerned with two major topics: Nuclear energy and Nuclear Techniques. Under Nuclear Energy, leaflets concerning the topics of "Radiation--A Fact of Life,""The Impact of a Fact: 1963 Test Ban Treaty,""Energy Needs and Nuclear Power,""Power Reactor Safety,""Transport,"…
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Vaginal eroticism: a replication study.
Alzate, H
1985-12-01
Vaginal eroticism was investigated in a group of 27 coitally experienced volunteers by means of systematic digital stimulation of both vaginal walls. Erogenous zones were found in all subjects, mainly located on the upper anterior wall and the lower posterior one. An orgasmic response was elicited by stimulation of these zones in 89% of the subjects. This study supports previous findings regarding vaginal eroticism. It does not support the existence of the discrete anatomical structure called the Grafenberg spot. It supports the contention that there are two distinct types of female orgasm, vaginally evoked and clitorally evoked. It also supports the finding that some women expel a fluid through the urethra at the time of orgasm. In this particular case the fluid was chemically indistinguishable from urine.
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ERIC Educational Resources Information Center
Ware, Elizabeth A.; Gelman, Susan A.; Kleinberg, Felicia
2013-01-01
An important developmental task is learning to organize experience by forming conceptual relations among entities. (For example, a "lion" and a "snake" can be linked because both are animals; a lion and a cage can be linked because the "lion" lives in the "cage".) We propose that representational medium…
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ERIC Educational Resources Information Center
Morris, James P.; Green, Steven R.; Marion, Brian; McCarthy, Gregory
2008-01-01
Functional magnetic resonance imaging (fMRI) has identified distinct brain regions in ventral occipitotemporal cortex (VOTC) and lateral occipitotemporal cortex (LOTC) that are differentially activated by pictures of faces and bodies. Recent work from our laboratory has shown that the strong LOTC activation evoked by bodies in which the face is…
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Distinct neural representations of placebo and nocebo effect
Freeman, Sonya; Yu, Rongjun; Egorova, Natalia; Chen, Xiaoyan; Kirsch, Irving; Claggett, Brian; Kaptchuk, Ted J.; Gollub, Randy L.; Kong, Jian
2015-01-01
Expectations shape the way we experience the world. In this study, we used fMRI to investigate how positive and negative expectation can changes pain experiences in the same cohort of subjects. We first manipulated subjects’ treatment expectation of the effectiveness of three inert creams, with one cream labeled “Lidocaine” (positive expectancy), one labeled “Capsaicin” (negative expectancy) and one labeled “Neutral” by surreptitiously decreasing, increasing, or not changing respectively, the intensity of the noxious stimuli administered following cream application. We then used fMRI to investigate the signal changes associated with administration of identical pain stimuli before and after the treatment and control creams. Twenty-four healthy adults completed the study. Results showed expectancy significantly modulated subjective pain ratings. After controlling for changes in the neutral condition, the subjective pain rating changes evoked by positive and negative expectancy were significantly associated. fMRI results showed that the expectation of an increase in pain induced significant fMRI signal changes in the insula, orbitofrontal cortex, and periaqueductal gray, whereas the expectation of pain relief evoked significant fMRI signal changes in the striatum. No brain regions were identified as common to both “Capsaicin” and “Lidocaine” conditioning. There was also no significant association between the brain response to identical noxious stimuli in the pain matrix evoked by positive and negative expectancy. Our findings suggest that positive and negative expectancy engage different brain networks to modulate our pain experiences, but, overall, these distinct patterns of neural activation result in a correlated placebo and nocebo behavioral response. PMID:25776211
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Shaw, Fu-Zen; Lee, Su-Ying; Chiu, Ted H
2006-03-01
To clarify the cortical evoked responses in the primary somatosensory cortex of the rat under states of waking, slow-wave sleep (SWS), paradoxical sleep (PS), and spike-wave discharges (SWDs), which are associated with absence seizure. Somatosensory evoked potentials (SEPs) in response to single- and paired-pulse stimulations under waking, SWS, PS, and SWDs were compared. SEPs to a single-pulse stimulus with regard to cortical spikes of sleep spindles and SWDs were also evaluated. Twenty Long Evans rats. Single- and paired-pulse innocuous electrical stimulations were applied to the tail of rats with chronically implanted electrodes in the primary somatosensory cortex and neck muscle under waking, SWS, PS, and SWDs. SEPs displayed distinct patterns under waking/PS and SWS/SWDs. The short-latency P1-N1 wave of the SEP was severely impeded during SWDs but not in other states. Reduction of the P1-N1 magnitude to the second stimulus of the paired-pulse stimulus for interstimulus intervals of < or = 300 milliseconds appeared in waking and PS states, but the decrease occurred only at particular interstimulus intervals under SWS. Interestingly, augmentation was found under SWDs. Moreover, cyclic augmentation of the P1-N1 magnitude was associated with spindle spikes, but cyclic reduction was observed with SWD spikes. Changes in SEPs are not only behavior dependent, but also phase locked onto ongoing brain activity. Distinct short-term plasticity of SEPs during sleep spindles or SWDs may merit further studies for seizure control and tactile information processing.
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FLUID MECHANICS OF ARTIFICIAL HEART VALVES
Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P
2009-01-01
SUMMARY 1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird’s-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10–15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage. PMID:19220329
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Fluid mechanics of artificial heart valves.
Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P
2009-02-01
1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.
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NASA Technical Reports Server (NTRS)
Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio
2003-01-01
The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.
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Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves
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
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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…
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Transmembrane protein diffusion in gel-supported dual-leaflet membranes.
Wang, Chih-Ying; Hill, Reghan J
2014-11-18
Tools to measure transmembrane-protein diffusion in lipid bilayer membranes have advanced in recent decades, providing a need for predictive theoretical models that account for interleaflet leaflet friction on tracer mobility. Here we address the fully three-dimensional flows driven by a (nonprotruding) transmembrane protein embedded in a dual-leaflet membrane that is supported above and below by soft porous supports (e.g., hydrogel or extracellular matrix), each of which has a prescribed permeability and solvent viscosity. For asymmetric configurations, i.e., supports with contrasting permeability, as realized for cells in contact with hydrogel scaffolds or culture media, the diffusion coefficient can reflect interleaflet friction. Reasonable approximations, for sufficiently large tracers on low-permeability supports, are furnished by a recent phenomenological theory from the literature. Interpreting literature data, albeit for hard-supported membranes, provides a theoretical basis for the phenomenological Stokes drag law as well as strengthening assertions that nonhydrodynamic interactions are important in supported bilayer systems, possibly leading to overestimates of the membrane/leaflet viscosity. Our theory provides a theoretical foundation for future experimental studies of tracer diffusion in gel-supported membranes.
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Costello, L. R.; Bassham, James A.; Calvin, Melvin
1982-01-01
Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of 14C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem origin. Electron microscope studies of petiolule sieve plate pores from excised leaflets showed substantially less callose appearing after treatment with EDTA than after H2O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants. Images PMID:16662189
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Joint small-angle X-ray and neutron scattering data analysis of asymmetric lipid vesicles
DOE Office of Scientific and Technical Information (OSTI.GOV)
Eicher, Barbara; Heberle, Frederick A.; Marquardt, Drew T.
2017-02-28
Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets. The scattering density profile model, however, comes at a cost of increased computational effortmore » but results in greater structural resolution, showing a slightly lower packing of lipids in the outer bilayer leaflet of ~120 nm diameter palmitoyloleoyl phosphatidylcholine (POPC) vesicles, compared to the inner leaflet. Here, analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K, i.e.above the melting transition temperature of the two lipids.« less
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Impact of written information on control and adherence in type 2 diabetes.
Caetano, Inês Rosendo Carvalho E Silva; Santiago, Luiz Miguel; Marques, Margarida
2018-02-01
Diabetes therapeutic education and information by leaflets is important. This study aimed to understand the effectiveness of written information to diabetic patients, after six months, in the control of diabetes and medication adherence. Non-pharmacological clinical trial. Randomized sample of diabetic patients of 65 volunteer doctors, distributed among the five health regions in Portugal. At the first appointment, patients were randomized in four groups (three intervention with validated leaflets and one control), leaflet reading being reinforced at the follow-up appointments in a 6-months period. Variables collected: HbA1c, home blood glucose, weight, waist circumference, blood pressure, cigarettes smoked, physical activity level, adherence to medication, medication, height, diabetes progression, age, sex and educational background. Descriptive and inferential statistics. From the 709 patients recruited, 702 were studied in this 6-months period with no statistical differences in the baseline variables studied. After six months of intervention, the adherence to medication improved in the leaflet group (p=0.034). This was noticed in those under 65 years of age (p=0.027), with diabetes for ≤ 5 years (p=0.010), with educational background up to 4 years (p=0.030) and 9 years (p=0.006) and with HbA1c ≥ 7% at the beginning of the study. Interventions with leaflets handed in primary healthcare to people with diabetes type 2 can bring benefits in what concerns adherence to therapeutics, namely in younger people with a less studies.
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Architecture of an in vivo-tissue engineered autologous conduit "Biovalve".
Hayashida, Kyoko; Kanda, Keiichi; Oie, Tomonori; Okamoto, Yoshihiro; Ishibashi-Ueda, Hatsue; Onoyama, Masaaki; Tajikawa, Tsutomu; Ohba, Kenkichi; Yaku, Hitoshi; Nakayama, Yasuhide
2008-07-01
As a practical concept of regenerative medicine, we have focused on in vivo tissue engineering utilizing the foreign body reaction. Plastic substrates for valvular leaflet organization, consisting of two pieces assembled with a small aperture were inserted into a microporous polyurethane conduit scaffold. The assembly was placed in the subcutaneous spaces of Japanese white rabbits for 1 month. After the substrates were pulled out from the harvested implant, valve leaflet-shaped membranous tissue was formed inside the tubular scaffold as designed. The valve leaflet was composed of the same collagen-rich tissue, with the absence of any elastic fiber, as that which had ingrown or covered the scaffold. No abnormal collection or infiltration of inflammatory cells in the leaflet and the scaffold could be demonstrated. According to the immunohistochemical staining, the leaflet was comprised of numerous vimentin- or alpha-SMA-positive cells, corresponding to fibroblasts or myofibroblats, but contained no desmin-positive cells. The analysis of the video data of the valve movement showed that, in synchronization with the backward flow in the diastolic phase, the valve closed rapidly and tightly and, in the transition phase of the flow direction, the valve opened smoothly without flapping or hitting the scaffold wall. Using mold designs, consisting of two different plastic substrates and the tubular scaffold, in conjunction with "in body tissue architecture," the complex 3-dimensional autologous conduit-typed Biovalve was developed for the first time. 2007 Wiley Periodicals, Inc.
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Chiappini, Bruno; Gregorini, Renato; De Remigis, Franco; Petrella, Licia; Villani, Carmine; Di Pietrantonio, Fabrizio; Pavicevic, Srdan; Mazzola, Alessandro
2009-08-01
The gold standard for the surgical treatment of prolapse of the posterior leaflet of the mitral valve (MV) for degenerative myxomatous disease has been represented by the quadrangular resection of the leaflet, according to the Carpentier technique. Since 2006 we performed a triangular resection of the prolapsing leaflet in 20 patients with myxomatous mitral regurgitation (MR). Seventeen patients (85%) underwent the triangular resection of P2; one patient (5%) had a triple scallops triangular resection (P1, P2, P3) and two (10%) a double scallops (P2, P3) resection. In this study, we report the immediate and mid-term clinical and echocardiographic results of a cohort of 20 patients, who underwent this technique. Thirty-day mortality was 0. Acute renal failure occurred in three patients (15%) and they resolved with conservative management. One patient (5%) required re-exploration for bleeding. At the mean follow-up of 13.1+/-4.2 months survival was 95%; one patient died of lymphoma during the follow-up time. All the cases were in New York Heart Association (NYHA) class I. Nineteen survivors underwent transthoracic echocardiography (TTE) (5), or transesophageal echocardiography (TEE) (13), performed by two skilled cardiologists. All patients showed no or trivial MV regurgitation. We believe that triangular resection of posterior MV leaflet (PMVL) provides excellent mid-term results providing the surgeon with a reliable and reproducible surgical option for myxomatous degenerative MV regurgitation.
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Mitral stenosis and hypertrophic obstructive cardiomyopathy: An unusual combination.
Hong, Joonhwa; Schaff, Hartzell V; Ommen, Steve R; Abel, Martin D; Dearani, Joseph A; Nishimura, Rick A
2016-04-01
Systolic anterior motion of mitral valve (MV) leaflets is a main pathophysiologic feature of left ventricular outflow tract (LVOT) obstruction in hypertrophic obstructive cardiomyopathy. Thus, restricted leaflet motion that occurs with MV stenosis might be expected to minimize outflow tract obstruction related to systolic anterior motion. From January 1993 through February 2015, we performed MV replacement and septal myectomy in 12 patients with mitral stenosis and hypertrophic obstructive cardiomyopathy at Mayo Clinic Hospital in Rochester, Minn. Preoperative data, echocardiographic images, operative records, and postoperative outcomes were reviewed. Mean (standard deviation) age was 70 (7.6) years. Preoperative mean (standard deviation) maximal LVOT pressure gradient was 75.0 (35.0) mm Hg; MV gradient was 13.7 (2.8) mm Hg. From echocardiographic images, 4 mechanisms of outflow tract obstruction were identified: systolic anterior motion without severe limitation in MV leaflet excursion, severe limitation in MV leaflet mobility with systolic anterior motion at the tip of the MV anterior leaflet, septal encroachment toward the LVOT, and MV displacement toward the LVOT by calcification. Mitral valve replacement and extended septal myectomy relieved outflow gradients in all patients, with no death or serious morbidity. Patients with mitral stenosis and hypertrophic obstructive cardiomyopathy have multiple LVOT obstruction mechanisms, and MV replacement may not be adequate treatment. We favor septal myectomy and MV replacement in this complex subset of hypertrophic obstructive cardiomyopathy. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
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Tricuspid valve repair for severe tricuspid regurgitation due to pacemaker leads.
Uehara, Kyokun; Minakata, Kenji; Watanabe, Kentaro; Sakaguchi, Hisashi; Yamazaki, Kazuhiro; Ikeda, Tadashi; Sakata, Ryuzo
2016-07-01
Tricuspid valve regurgitation due to pacemaker leads is a well-known complication. Although some reports have suggested that pacemaker leads should be surgically explanted, strongly adhered leads cannot always be removed. The aim of this study was to describe our tricuspid valve repair techniques with pacemaker leads left in situ. Our retrospective study investigated 6 consecutive patients who required tricuspid valve surgery for severe regurgitation induced by pacemaker leads. From the operative findings, we identified 3 patterns of tricuspid valve and pacemaker lead involvement. In 3 patients, the leads were caught in the chordae, in 2 patients, tricuspid regurgitation was caused by lead impingement on the septal leaflet, and in 3 patients, tricuspid valve leaflets had been perforated by the pacemaker leads. During surgery, all leads were left in situ after being separated from the leaflet or valvular apparatus. In addition, suture annuloplasty was performed for annular dilatation in all cases. In one patient, the lead was reaffixed to the annulus after the posterior leaflet was cut back towards the annulus, and the leaflet was then closed. There was one hospital death due to sepsis. The degree of tricuspid regurgitation was trivial in all surviving patients at discharge. During a mean follow-up of 21 months, one patient died from pneumonia 20 months after tricuspid valve repair. In patients undergoing tricuspid valve surgery due to severe tricuspid regurgitation caused by pacemaker leads, the leads can be left in situ after proper repair with annuloplasty. © The Author(s) 2016.
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Lapenna, Elisabetta; De Bonis, Michele; Verzini, Alessandro; La Canna, Giovanni; Ferrara, David; Calabrese, Maria Chiara; Taramasso, Maurizio; Alfieri, Ottavio
2010-06-01
This study assesses the results of the 'clover technique' (suturing together the middle point of the free edges of the tricuspid leaflets) for the treatment of tricuspid regurgitation (TR) due to severe prolapse or tethering. From 2001, 66 patients with severe TR due to prolapsing or tethered leaflets underwent 'clover repair'. Annuloplasty was associated in 64 patients (97%). The aetiology of TR was degenerative in 52 cases (79%), post-traumatic in eight (12%) and secondary to dilated cardiomyopathy (DCM) in six (9%). The main mechanism of TR was prolapse/flail of one leaflet in 15 patients (23%), of two leaflets in 31 (47%) and of all three leaflets in 14 (21%). The remaining six patients (9%) presented with severe leaflets' tethering. Four deaths (6%) occurred during hospitalisation and one patient died 3.6 years after surgery. Survival was 91 + or - 4.1% at 5 years. Follow-up of the 62 hospital survivors was 100% complete (mean length 3.5 + or - 1.6 years, range 13 months-7.1 years). At the last echocardiogram, no or mild TR was detected in 55 (88.7%) patients, moderate (2+/4+) in six (9.6%) and severe (4+/4+) in one patient (1.6%). Mean tricuspid valve area and gradient were 4.3 + or - 0.6 cm(2) and 2.8 + or -1.4 mmHg. In six patients, stress echocardiography was performed and no signs of tricuspid stenosis were detected. At the multivariable analysis, the degree of TR at hospital discharge was identified as the only predictor of TR > or = 2+ at follow-up. Midterm clinical and echocardiographic results confirm the role of the 'clover technique' in the surgical treatment of TR due to lesions, which are unlikely to be effectively treatable by annuloplasty alone. Copyright 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.
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Bol Raap, Goris; Koning, Anton H J; Scohy, Thierry V; ten Harkel, A Derk-Jan; Meijboom, Folkert J; Kappetein, A Pieter; van der Spek, Peter J; Bogers, Ad J J C
2007-02-16
This study was done to investigate the potential additional role of virtual reality, using three-dimensional (3D) echocardiographic holograms, in the postoperative assessment of tricuspid valve function after surgical closure of ventricular septal defect (VSD). 12 data sets from intraoperative epicardial echocardiographic studies in 5 operations (patient age at operation 3 weeks to 4 years and bodyweight at operation 3.8 to 17.2 kg) after surgical closure of VSD were included in the study. The data sets were analysed as two-dimensional (2D) images on the screen of the ultrasound system as well as holograms in an I-space virtual reality (VR) system. The 2D images were assessed for tricuspid valve function. In the I-Space, a 6 degrees-of-freedom controller was used to create the necessary projectory positions and cutting planes in the hologram. The holograms were used for additional assessment of tricuspid valve leaflet mobility. All data sets could be used for 2D as well as holographic analysis. In all data sets the area of interest could be identified. The 2D analysis showed no tricuspid valve stenosis or regurgitation. Leaflet mobility was considered normal. In the virtual reality of the I-Space, all data sets allowed to assess the tricuspid leaflet level in a single holographic representation. In 3 holograms the septal leaflet showed restricted mobility that was not appreciated in the 2D echocardiogram. In 4 data sets the posterior leaflet and the tricuspid papillary apparatus were not completely included. This report shows that dynamic holographic imaging of intraoperative postoperative echocardiographic data regarding tricuspid valve function after VSD closure is feasible. Holographic analysis allows for additional tricuspid valve leaflet mobility analysis. The large size of the probe, in relation to small size of the patient, may preclude a complete data set. At the moment the requirement of an I-Space VR system limits the applicability in virtual reality 3D echocardiography in clinical practice.
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Kubota, Kayoko; Otsuji, Yutaka; Ueno, Tetsuya; Koriyama, Chihaya; Levine, Robert A.; Sakata, Ryuzo; Tei, Chuwa
2010-01-01
Objective Diastolic subvalvular mitral leaflet tethering by left ventricular remodeling that restricts leaflet opening in the presence of annular size reduction by surgery for ischemic mitral regurgitation potentially causes functional mitral stenosis in the absence of organic leaflet lesions. Exercise, known to worsen systolic tethering and ischemic mitral regurgitation, might also dynamically exacerbate such mitral stenosis by increasing tethering. This study evaluates the mechanism and response of such mitral stenosis to exercise. Methods We measured the diastolic mitral valve area, annular area, and peak and mean transmitral pressure gradient by echocardiography in 20 healthy individuals and 31 patients who underwent surgical annuloplasty for ischemic mitral regurgitation. Results Although the mitral valve area and annular area did not significantly differ in healthy individuals (4.7 ± 0.6 cm2 vs 5.2 ± 0.6 cm2, not significant), mitral valve area was significantly smaller than the annular area in patients after annuloplasty (1.6 ± 0.2 cm2 vs 3.3 ± 0.5 cm2, P < .01). The mitral valve area was less than 1.5 cm2 only after the surgery (P < .01) and was significantly correlated with restricted leaflet opening (r2 = 0.74, P <.001), left ventricular dilatation (r2 = 0.17, P <.05), and New York Heart Association functional class (P <. 05). Exercise stress echocardiography of 12 patients demonstrated dynamic worsening in functional mitral stenosis (mitral valve area: 2.0 ± 0.5 cm2 to 1.4 ± 0.2 cm2, P < .01; mean pressure gradient: 1.5 ± 0.9 mm Hg to 6.0 ± 2.2 mm Hg, P < .01). Conclusions Persistent subvalvular leaflet tethering in the presence of annular size reduction by surgery in ischemic mitral regurgitation frequently causes functional mitral stenosis at the leaflet tip level, which is related to heart failure symptoms and can be dynamic with significant exercise-induced worsening. PMID:20122701
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Khalique, Omar K; Hahn, Rebecca T; Gada, Hemal; Nazif, Tamim M; Vahl, Torsten P; George, Isaac; Kalesan, Bindu; Forster, Molly; Williams, Mathew B; Leon, Martin B; Einstein, Andrew J; Pulerwitz, Todd C; Pearson, Gregory D N; Kodali, Susheel K
2014-08-01
This study sought to determine the impact of quantity and location of aortic valve calcification (AVC) on paravalvular regurgitation (PVR) and rates of post-dilation (PD) immediately after transcatheter aortic valve replacement (TAVR). The impact of AVC in different locations within the aortic valve complex is incompletely understood. This study analyzed 150 patients with severe, symptomatic aortic stenosis who underwent TAVR. Total AVC volume scores were calculated from contrast-enhanced multidetector row computed tomography imaging. AVC was divided by leaflet sector and region (Leaflet, Annulus, left ventricular outflow tract [LVOT]), and a combination of LVOT and Annulus (AnnulusLVOT). Asymmetry was assessed. Receiver-operating characteristic analysis was performed with greater than or equal to mild PVR and PD as classification variables. Logistic regression was performed. Quantity of and asymmetry of AVC for all regions of the aortic valve complex predicted greater than or equal to mild PVR by receiver-operating characteristic analysis (area under the curve = 0.635 to 0.689), except Leaflet asymmetry. Receiver-operating characteristic analysis for PD was significant for quantity and asymmetry of AVC in all regions, with higher area under the curve values than for PVR (area under the curve = 0.648 to 0.741). On multivariable analysis, Leaflet and AnnulusLVOT calcification were independent predictors of both PVR and PD regardless of multidetector row computed tomography area cover index. Quantity and asymmetry of AVC in all regions of the aortic valve complex predict greater than or equal to mild PVR and performance of PD, with the exception of Leaflet asymmetry. Quantity of AnnulusLVOT and Leaflet calcification independently predict PVR and PD when taking into account multidetector row computed tomography area cover index. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
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Cechmanek, Paula Bernice; McFarlane, Sarah
2017-08-01
The retinal pigment epithelium (RPE) is a specialized monolayer of epithelial cells that forms a tight barrier surrounding the neural retina. RPE cells are indispensable for mature photoreceptor renewal and survival, yet how the initial RPE cell population expands around the neural retina during eye development is poorly understood. Here we characterize the differentiation, proliferation, and movements of RPE progenitors in the Zebrafish embryo over the period of optic cup morphogenesis. RPE progenitors are present in the dorsomedial eye vesicle shortly after eye vesicle evagination. We define two separate phases that allow for full RPE expansion. The first phase involves a previously uncharacterized antero-wards expansion of the RPE progenitor domain in the inner eye vesicle leaflet, driven largely by an increase in cell number. During this phase, RPE progenitors start to express differentiation markers. In the second phase, the progenitor domain stretches in the dorsoventral and posterior axes, involving cell movements and shape changes, and coinciding with optic cup morphogenesis. Significantly, cell division is not required for RPE expansion. RPE development to produce the monolayer epithelium that covers the back of the neural retina occurs in two distinct phases driven by distinct mechanisms. Developmental Dynamics 246:598-609, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
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Olfactory fingerprints for major histocompatibility complex-determined body odors.
Schaefer, M L; Young, D A; Restrepo, D
2001-04-01
Recognition of individual body odors is analogous to human face recognition in that it provides information about identity. Individual body odors determined by differences at the major histocompatibility complex (MHC or H-2) have been shown to influence mate choice, pregnancy block, and maternal behavior in mice. Unfortunately, the mechanism and extent of the main olfactory bulb (MOB) and accessory olfactory bulb (AOB) involvement in the discrimination of animals according to H-2-type has remained ambiguous. Here we study the neuronal activation patterns evoked in the MOB in different individuals on exposure to these complex, biologically meaningful sensory stimuli. We demonstrate that body odors from H-2 disparate mice evoke overlapping but distinct maps of neuronal activation in the MOB. The spatial patterns of odor-evoked activity are sufficient to be used like fingerprints to predict H-2 identity using a novel computer algorithm. These results provide functional evidence for discrimination of H-2-determined body odors in the MOB, but do not preclude a role for the AOB. These data further our understanding of the neural strategies used to decode socially relevant odors.
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Tiedt, Hannes O; Beier, Klaus M; Lueschow, Andreas; Pauls, Alfred; Weber, Joachim E
2014-12-01
Viewing personally familiar and loved faces evokes a distinct pattern of brain activity as demonstrated by research employing imaging and electrophysiological methods. The aim of the current investigation was to study the perception of loved faces combined with recalling past emotional experiences using whole-head magnetoencephalograpy (MEG). Twenty-eight participants (fourteen female) viewed photographs of their romantic partner as well as of two long-term friends while imagining a positive emotional encounter with the respective person. Face-stimuli evoked a slow and sustained shift of magnetic activity from 300ms post-stimulus onwards which differentiated loved from friends' faces in female participants and left-sided sensors only. This late-latency evoked magnetic field resembled (as its magnetic counterpart) ERP-modulations by affective content and memory, most notably the late positive potential (LPP). We discuss our findings in the light of studies suggesting greater responsiveness to affective cues in women as well as sex differences in autobiographical and emotional memory. Copyright © 2014 Elsevier B.V. All rights reserved.
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Kinetics of fast short-term depression are matched to spike train statistics to reduce noise.
Khanbabaie, Reza; Nesse, William H; Longtin, Andre; Maler, Leonard
2010-06-01
Short-term depression (STD) is observed at many synapses of the CNS and is important for diverse computations. We have discovered a form of fast STD (FSTD) in the synaptic responses of pyramidal cells evoked by stimulation of their electrosensory afferent fibers (P-units). The dynamics of the FSTD are matched to the mean and variance of natural P-unit discharge. FSTD exhibits switch-like behavior in that it is immediately activated with stimulus intervals near the mean interspike interval (ISI) of P-units (approximately 5 ms) and recovers immediately after stimulation with the slightly longer intervals (>7.5 ms) that also occur during P-unit natural and evoked discharge patterns. Remarkably, the magnitude of evoked excitatory postsynaptic potentials appear to depend only on the duration of the previous ISI. Our theoretical analysis suggests that FSTD can serve as a mechanism for noise reduction. Because the kinetics of depression are as fast as the natural spike statistics, this role is distinct from previously ascribed functional roles of STD in gain modulation, synchrony detection or as a temporal filter.
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Attili, Seetharamaiah; Hughes, Simon M.
2014-01-01
Movements in animals arise through concerted action of neurons and skeletal muscle. General anaesthetics prevent movement and cause loss of consciousness by blocking neural function. Anaesthetics of the amino amide-class are thought to act by blockade of voltage-gated sodium channels. In fish, the commonly used anaesthetic tricaine methanesulphonate, also known as 3-aminobenzoic acid ethyl ester, metacaine or MS-222, causes loss of consciousness. However, its role in blocking action potentials in distinct excitable cells is unclear, raising the possibility that tricaine could act as a neuromuscular blocking agent directly causing paralysis. Here we use evoked electrical stimulation to show that tricaine efficiently blocks neural action potentials, but does not prevent directly evoked muscle contraction. Nifedipine-sensitive L-type Cav channels affecting movement are also primarily neural, suggesting that muscle Nav channels are relatively insensitive to tricaine. These findings show that tricaine used at standard concentrations in zebrafish larvae does not paralyse muscle, thereby diminishing concern that a direct action on muscle could mask a lack of general anaesthesia. PMID:25090007
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Human auditory steady state responses to binaural and monaural beats.
Schwarz, D W F; Taylor, P
2005-03-01
Binaural beat sensations depend upon a central combination of two different temporally encoded tones, separately presented to the two ears. We tested the feasibility to record an auditory steady state evoked response (ASSR) at the binaural beat frequency in order to find a measure for temporal coding of sound in the human EEG. We stimulated each ear with a distinct tone, both differing in frequency by 40Hz, to record a binaural beat ASSR. As control, we evoked a beat ASSR in response to both tones in the same ear. We band-pass filtered the EEG at 40Hz, averaged with respect to stimulus onset and compared ASSR amplitudes and phases, extracted from a sinusoidal non-linear regression fit to a 40Hz period average. A 40Hz binaural beat ASSR was evoked at a low mean stimulus frequency (400Hz) but became undetectable beyond 3kHz. Its amplitude was smaller than that of the acoustic beat ASSR, which was evoked at low and high frequencies. Both ASSR types had maxima at fronto-central leads and displayed a fronto-occipital phase delay of several ms. The dependence of the 40Hz binaural beat ASSR on stimuli at low, temporally coded tone frequencies suggests that it may objectively assess temporal sound coding ability. The phase shift across the electrode array is evidence for more than one origin of the 40Hz oscillations. The binaural beat ASSR is an evoked response, with novel diagnostic potential, to a signal that is not present in the stimulus, but generated within the brain.
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Opening and Closing of Oxalis Leaves in Response to Light Stimuli
ERIC Educational Resources Information Center
Nakanishi, Fumi; Nakazawa, Masami; Katayama, Nobuyasu
2005-01-01
Fully opened leaves of potted plants of "Oxalis corymbosa" DC. closed completely by folding their leaflets downward after being kept in the dark for two hours. The folded leaflets, then moved upward gradually after exposure to light. We developed a simple method to measure the leaf movement. A paper protractor folded every 10[degrees] was devised…
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A Working Woman's Guide To Her Job Rights. Leaflet 55.
ERIC Educational Resources Information Center
Women's Bureau (DOL), Washington, DC.
This leaflet presents general information about legislation that affects women when they are seeking a job, while they are on the job, and when they retire. Emphasis is on Federal laws as of November, 1978. Some of the topics include employment services, protection against sex and age discrimination, minimum wages and overtime pay, discrimination…
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Shimbo, Mai; Watanabe, Hiroyuki; Kimura, Shunsuke; Terada, Mai; Iino, Takako; Iino, Kenji; Ito, Hiroshi
2015-01-01
Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) can provide unique visualization and better understanding of the relationship among cardiac structures. Here, we report the case of an 85-year-old woman with an obstructed mitral prosthetic valve diagnosed promptly by RT3D-TEE, which clearly showed a leaflet stuck in the closed position. The opening and closing angles of the valve leaflets measured by RT3D-TEE were compatible with those measured by fluoroscopy. Moreover, RT3D-TEE revealed, in the ring of the prosthetic valve, thrombi that were not visible on fluoroscopy. RT3D-TEE might be a valuable diagnostic technique for prosthetic mitral valve thrombosis. © 2014 Wiley Periodicals, Inc.
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Menstruation experiences of South African women belonging to the ama-Xhosa ethnic group.
Padmanabhanunni, Anita; Jaffer, Labeeqah; Steenkamp, Jeanette
2017-09-15
A growing body of research has emphasised the salience of cultural beliefs and traditional practices to women's experiences of menstruation. Relatively less research has, however, been undertaken in South Africa. This study explored the experience of menstruation among women from the ama-Xhosa ethnic group, one of the largest ethnic groups in the country. Among the ama-Xhosa, there are distinct cultural practices associated with menstruation, including the female rite of passage (intonjane) and virginity testing (inkciyo). However, few studies have explored the experience of menstruation for women from this cultural group. This study involved the synthesis of data from individual interviews and focus group discussions conducted among a sample of ama-Xhosa women. The data were analysed using thematic analysis. Distinctive findings included women's participation in traditional cultural practices of intonjane and inkciyo and the presence of cultural taboos associated with menstruation. Women's narratives revealed strong ambivalence regarding these practices. On the one hand, they wanted to adhere to traditional practices but experienced these customs as evoking discomfort and shame. The study confirmed the prevalence of negative constructions of menstruation. Positive appraisals of menstruation as evoking joy and happiness were also encountered.
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Tricuspid Valve Dysfunction Following Pacemaker or Cardioverter-Defibrillator Implantation.
Chang, James D; Manning, Warren J; Ebrille, Elisa; Zimetbaum, Peter J
2017-05-09
The potential for cardiac implantable electronic device leads to interfere with tricuspid valve (TV) function has gained increasing recognition as having hemodynamic and clinical consequences associated with incremental morbidity and death. The diagnosis and treatment of lead-related (as distinct from functional) tricuspid regurgitation pose unique challenges. Because of pitfalls in routine diagnostic imaging, a high level of clinical suspicion must be maintained to avoid overlooking the possibility that worsening heart failure is a consequence of mechanical interference with TV leaflet mobility or coaptation and is amenable to lead extraction or valve repair or replacement. The future of cardiac implantable electronic devices includes pacing and perhaps defibrillation without a lead traversing the TV. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
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Music training relates to the development of neural mechanisms of selective auditory attention.
Strait, Dana L; Slater, Jessica; O'Connell, Samantha; Kraus, Nina
2015-04-01
Selective attention decreases trial-to-trial variability in cortical auditory-evoked activity. This effect increases over the course of maturation, potentially reflecting the gradual development of selective attention and inhibitory control. Work in adults indicates that music training may alter the development of this neural response characteristic, especially over brain regions associated with executive control: in adult musicians, attention decreases variability in auditory-evoked responses recorded over prefrontal cortex to a greater extent than in nonmusicians. We aimed to determine whether this musician-associated effect emerges during childhood, when selective attention and inhibitory control are under development. We compared cortical auditory-evoked variability to attended and ignored speech streams in musicians and nonmusicians across three age groups: preschoolers, school-aged children and young adults. Results reveal that childhood music training is associated with reduced auditory-evoked response variability recorded over prefrontal cortex during selective auditory attention in school-aged child and adult musicians. Preschoolers, on the other hand, demonstrate no impact of selective attention on cortical response variability and no musician distinctions. This finding is consistent with the gradual emergence of attention during this period and may suggest no pre-existing differences in this attention-related cortical metric between children who undergo music training and those who do not. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
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Submillisecond unmasked subliminal visual stimuli evoke electrical brain responses.
Sperdin, Holger F; Spierer, Lucas; Becker, Robert; Michel, Christoph M; Landis, Theodor
2015-04-01
Subliminal perception is strongly associated to the processing of meaningful or emotional information and has mostly been studied using visual masking. In this study, we used high density 256-channel EEG coupled with an liquid crystal display (LCD) tachistoscope to characterize the spatio-temporal dynamics of the brain response to visual checkerboard stimuli (Experiment 1) or blank stimuli (Experiment 2) presented without a mask for 1 ms (visible), 500 µs (partially visible), and 250 µs (subliminal) by applying time-wise, assumption-free nonparametric randomization statistics on the strength and on the topography of high-density scalp-recorded electric field. Stimulus visibility was assessed in a third separate behavioral experiment. Results revealed that unmasked checkerboards presented subliminally for 250 µs evoked weak but detectable visual evoked potential (VEP) responses. When the checkerboards were replaced by blank stimuli, there was no evidence for the presence of an evoked response anymore. Furthermore, the checkerboard VEPs were modulated topographically between 243 and 296 ms post-stimulus onset as a function of stimulus duration, indicative of the engagement of distinct configuration of active brain networks. A distributed electrical source analysis localized this modulation within the right superior parietal lobule near the precuneus. These results show the presence of a brain response to submillisecond unmasked subliminal visual stimuli independently of their emotional saliency or meaningfulness and opens an avenue for new investigations of subliminal stimulation without using visual masking. © 2014 Wiley Periodicals, Inc.
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Melcher, J R; Guinan, J J; Knudson, I M; Kiang, N Y
1996-04-01
Brainstem regions involved in generating the brainstem auditory evoked potential (BAEP) were identified by examining the effects of lesions on the click-evoked BAEP in cats. An excitotoxin, kainic acid, was injected into various parts of the cochlear nucleus (CN) or into the superior olivary complex (SOC). The locations of the resulting lesions were correlated with the changes produced in the various extrema of the BAEP waveforms. The results indicate that: (1) the earliest BAEP extrema (P1, N1 (recorded between vertex and the earbar ipsilateral to the stimulus) and P1a, P1b, (vertex to contralateral earbar)) are generated by cells with somata peripheral to the CN; (2) P2 is primarily generated by posterior anteroventral CN (AVCNp) and anterior posteroventral CN (PVCNa) cells; (3) SOC, anterior anteroventral CN (AVCNa), AVCNp, and PVCNa cells are involved in generating P3; (4) AVCNa cells are the main CN cells involved in P4, N4, and P5 generation; (5) both ipsilateral and contralateral SOC cells have a role in generating monaurally evoked P4 and P5; and (6) P5 is generated by cells with characteristic frequencies below 10 kHz. From (2) and (4), it is clear that P2 and P4-P5 are generated by cells in distinct, parallel pathways.
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Gibson, William S; Cho, Shinho; Abulseoud, Osama A; Gorny, Krzysztof R; Felmlee, Joel P; Welker, Kirk M; Klassen, Bryan T; Min, Hoon-Ki; Lee, Kendall H
2017-01-01
Abstract Deep brain stimulation (DBS) of the ventral capsule/ventral striatum (VC/VS) is an investigational therapy for treatment-resistant obsessive-compulsive disorder. The ability of VC/VS DBS to evoke spontaneous mirth in patients, often accompanied by smiling and laughter, is clinically well documented. However, the neural correlates of DBS-evoked mirth remain poorly characterized. Patients undergoing VC/VS DBS surgery underwent intraoperative evaluation in which mirth-inducing and non-mirth-inducing stimulation localizations were identified. Using dynamic causal modeling (DCM) for fMRI, the effect of mirth-inducing DBS on functional and effective connectivity among established nodes in limbic cortico-striato-thalamo-cortical (CSTC) circuitry was investigated. Both mirth-inducing and non-mirth-inducing VC/VS DBS consistently resulted (conjunction, global null, family-wise error-corrected P < 0.05) in activation of amygdala, ventral striatum, and mediodorsal thalamus. However, only mirth-inducing DBS resulted in functional inhibition of anterior cingulate cortex. Dynamic causal modeling revealed that mirth-inducing DBS enhanced effective connectivity from anterior cingulate to ventral striatum, while attenuating connectivity from thalamus to ventral striatum relative to non-mirth-inducing stimulation. These results suggest that DBS-evoked mood elevation is accompanied by distinct patterns of limbic thalamocortical connectivity. Using the novel combination of DBS-evoked mood alteration and functional MRI in human subjects, we provide new insights into the network-level mechanisms that influence affect. PMID:27001680
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Crosslinking EEG time-frequency decomposition and fMRI in error monitoring.
Hoffmann, Sven; Labrenz, Franziska; Themann, Maria; Wascher, Edmund; Beste, Christian
2014-03-01
Recent studies implicate a common response monitoring system, being active during erroneous and correct responses. Converging evidence from time-frequency decompositions of the response-related ERP revealed that evoked theta activity at fronto-central electrode positions differentiates correct from erroneous responses in simple tasks, but also in more complex tasks. However, up to now it is unclear how different electrophysiological parameters of error processing, especially at the level of neural oscillations are related, or predictive for BOLD signal changes reflecting error processing at a functional-neuroanatomical level. The present study aims to provide crosslinks between time domain information, time-frequency information, MRI BOLD signal and behavioral parameters in a task examining error monitoring due to mistakes in a mental rotation task. The results show that BOLD signal changes reflecting error processing on a functional-neuroanatomical level are best predicted by evoked oscillations in the theta frequency band. Although the fMRI results in this study account for an involvement of the anterior cingulate cortex, middle frontal gyrus, and the Insula in error processing, the correlation of evoked oscillations and BOLD signal was restricted to a coupling of evoked theta and anterior cingulate cortex BOLD activity. The current results indicate that although there is a distributed functional-neuroanatomical network mediating error processing, only distinct parts of this network seem to modulate electrophysiological properties of error monitoring.
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Bapat, Shweta S; Patel, Harshali K; Sansgiry, Sujit S
2017-10-16
In this study, we evaluate the role of information anxiety and information load on the intention to read information from prescription drug information leaflets (PILs). These PILs were developed based on the principals of information load and consumer information processing. This was an experimental prospective repeated measures study conducted in the United States where 360 (62% response rate) university students (>18 years old) participated. Participants were presented with a scenario followed by exposure to the three drug product information sources used to operationalize information load. The three sources were: (i) current practice; (ii) pre-existing one-page text only; and (iii) interventional one-page prototype PILs designed for the study. Information anxiety was measured as anxiety experienced by the individual when encountering information. The outcome variable of intention to read PILs was defined as the likelihood that the patient will read the information provided in the leaflets. A survey questionnaire was used to capture the data and the objectives were analyzed by performing a repeated measures MANOVA using SAS version 9.3. When compared to current practice and one-page text only leaflets, one-page PILs had significantly lower scores on information anxiety ( p < 0.001) and information load ( p < 0.001). The intention to read was highest and significantly different ( p < 0.001) for PILs as compared to current practice or text only leaflets. Information anxiety and information load significantly impacted intention to read ( p < 0.001). Newly developed PILs increased patient's intention to read and can help in improving the counseling services provided by pharmacists.
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Bapat, Shweta S.; Patel, Harshali K.; Sansgiry, Sujit S.
2017-01-01
In this study, we evaluate the role of information anxiety and information load on the intention to read information from prescription drug information leaflets (PILs). These PILs were developed based on the principals of information load and consumer information processing. This was an experimental prospective repeated measures study conducted in the United States where 360 (62% response rate) university students (>18 years old) participated. Participants were presented with a scenario followed by exposure to the three drug product information sources used to operationalize information load. The three sources were: (i) current practice; (ii) pre-existing one-page text only; and (iii) interventional one-page prototype PILs designed for the study. Information anxiety was measured as anxiety experienced by the individual when encountering information. The outcome variable of intention to read PILs was defined as the likelihood that the patient will read the information provided in the leaflets. A survey questionnaire was used to capture the data and the objectives were analyzed by performing a repeated measures MANOVA using SAS version 9.3. When compared to current practice and one-page text only leaflets, one-page PILs had significantly lower scores on information anxiety (p < 0.001) and information load (p < 0.001). The intention to read was highest and significantly different (p < 0.001) for PILs as compared to current practice or text only leaflets. Information anxiety and information load significantly impacted intention to read (p < 0.001). Newly developed PILs increased patient’s intention to read and can help in improving the counseling services provided by pharmacists. PMID:29035337
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Afilalo, Jonathan; Grapsa, Julia; Nihoyannopoulos, Petros; Beaudoin, Jonathan; Gibbs, J. Simon R.; Channick, Richard N.; Langleben, David; Rudski, Lawrence G.; Hua, Lanqi; Handschumacher, Mark D.; Picard, Michael H.; Levine, Robert A.
2015-01-01
Background Tricuspid regurgitation (TR) is a risk factor for mortality in pulmonary hypertension (PH). TR severity varies among patients with comparable degrees of PH and right ventricular (RV) remodeling. The contribution of leaflet adaptation to the pathophysiology of TR has yet to be examined. We hypothesized that tricuspid leaflet area (TLA) is increased in PH, and that its size relative to RV remodeling determines TR severity. Methods and Results A prospective cohort of 255 patients with PH from pre- and post-capillary etiologies was assembled from two centers. Patients underwent a 3-D echocardiogram focused on the tricuspid apparatus. TLA was measured with the Omni custom software package. Compared with normal controls, PH patients had a twofold increase in RV volumes, 62% increase in annulus area, and 49% increase in TLA. Those with severe TR demonstrated inadequate increase in TLA relative to the closure area, such that the ratio of TLA-to-closure area <1.78 was highly predictive of severe TR (odds ratio 68.7; 95% CI 16.2, 292.7). The median vena contracta width was 8.5 mm in the group with small TLA and large closure area as opposed to 4.8 mm in the group with large TLA and large closure area. Conclusions TLA plays a significant role in determining which patients with PH develop severe functional TR. The ratio of TLA-to-closure area, reflecting the balance between leaflet adaptation vs. annular dilation and tethering forces, is an indicator of TR severity that may identify which patients stand to benefit from leaflet augmentation during tricuspid valve repair. PMID:25977303
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Qiao, Wei-Hua; Liu, Peng; Hu, Dan; Al Shirbini, Mahmoud; Zhou, Xian-Ming; Dong, Nian-Guo
2018-02-01
Antigenicity of xenogeneic tissues is the major obstacle to increased use of these materials in clinical medicine. Residual xenoantigens in decellularized tissue elicit the immune response after implantation, causing graft failure. With this in mind, the potential use is proposed of three protein solubilization-based protocols for porcine aortic valve leaflets decellularization. It was demonstrated that hydrophile solubilization alone 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 good preservation of the structure and mechanical properties. In contrast, a previously reported method using Triton X-100, sodium deoxycholate and IGEPAL CA-630 resulted in a complete removal of all cells and MHC I, but with remaining α-Gal epitope. 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 illustrate that the SHLS protocol could be considered as a promising decellularization method for the decellularization of xenogeneic tissues in tissue engineering and regenerative medicine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
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El-Khani, A; Cartwright, K; Redmond, A; Calam, R
2016-01-01
Risks to the mental health of children and families exposed to conflict in Syria are of such magnitude that research identifying how best to deliver psychological first aid is urgently required. This study tested the feasibility of a novel approach to large-scale distribution of information and data collection. Routine humanitarian deliveries of bread by a bakery run by a non-governmental organisation (NGO) were used to distribute parenting information leaflets and questionnaires to adults looking after children in conflict zones inside Syria. Study materials were emailed to a project worker in Turkey. Leaflets and questionnaires requesting feedback were transported alongside supplies to a bakery in Syria, and then packed with flatbreads. Three thousand bread-packs were distributed, from three distribution points to which questionnaires were returned, and then taken to Turkey and dispatched to the UK. Notwithstanding delays, 3000 leaflets and questionnaires were successfully distributed over 2 days. Questionnaire return yielded 1783 responses, a 59.5% return rate. Overall ratings of the usefulness of the leaflet were 1060 (59.5%) 'quite a lot' and 339 (19.0%) 'a great deal'. Content analysis was used to code 400 respondent comments. Four themes emerged; positive comments about the leaflet, suggestions for modifications, descriptions of children's needs and the value respondents placed on faith. Findings indicate the willingness of NGO staff and volunteers to assist in research, the remarkable willingness of caregivers to respond and the value of brief advice. It demonstrates the scope for using existing humanitarian routes to distribute information and receive feedback even in high-risk settings.
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Effects of CO2 Concentration on Rubisco Activity, Amount, and Photosynthesis in Soybean Leaves 1
Campbell, William J.; Allen, L. H.; Bowes, George
1988-01-01
Growth at an elevated CO2 concentration resulted in an enhanced capacity for soybean (Glycine max L. Merr. cv Bragg) leaflet photosynthesis. Plants were grown from seed in outdoor controlled-environment chambers under natural solar irradiance. Photosynthetic rates, measured during the seed filling stage, were up to 150% greater with leaflets grown at 660 compared to 330 microliters of CO2 per liter when measured across a range of intercellular CO2 concentrations and irradiance. Soybean plants grown at elevated CO2 concentrations had heavier pod weights per plant, 44% heavier with 660 compared to 330 microliters of CO2 per liter grown plants, and also greater specific leaf weights. Ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) activity showed no response (mean activity of 96 micromoles of CO2 per square meter per second expressed on a leaflet area basis) to short-term (∼1 hour) exposures to a range of CO2 concentrations (110-880 microliters per liter), nor was a response of activity (mean activity of 1.01 micromoles of CO2 per minute per milligram of protein) to growth CO2 concentration (160-990 microliters per liter) observed. The amount of rubisco protein was constant, as growth CO2 concentration was varied, and averaged 55% of the total leaflet soluble protein. Although CO2 is required for activation of rubisco, results indicated that within the range of CO2 concentrations used (110-990 microliters per liter), rubisco activity in soybean leaflets, in the light, was not regulated by CO2. PMID:16666460
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Saji, Mike; Rossi, Ann M; Ailawadi, Gorav; Dent, John; Ragosta, Michael; Lim, D Scott
2016-02-01
We evaluated intracardiac echocardiography (ICE) for adjunctively guiding the MitraClip procedure in patients with prior surgical rings. Transesophageal echocardiography (TEE) is the standard imaging modality used to guide the MitraClip procedure (Abbott Vascular, CA). However, in patients with post-surgical anatomy, clear imaging of the mitral valve leaflets may be complex because of shadowing from the surgical ring. In these patients, TEE may be suboptimal for guiding the procedure, even using three-dimensional imaging. This retrospective analysis included data from 121 consecutive patients with mitral regurgitation who underwent MitraClip procedures at the University of Virginia. ICE was used adjunctively when there was difficulty with TEE, particularly for assessing the insertion of the posterior leaflet into the MitraClip's arms. The ICE catheter was introduced transarterially into the left ventricle and flexed to obtain the short-axis view. Six patients had prior surgical rings, and in five, we used adjunctive ICE. The etiology of the mitral regurgitation was prolapse of the posterior leaflet in one patient and restriction of the posterior leaflet due to ischemic tethering in the remainder. All images were obtained from the left ventricle, and were adequate for assessing posterior leaflet insertion and the perpendicularity of the MitraClip arms. The procedural success rate was 80%. There was no adverse event related to the ICE procedure. Mitral valve repair with the MitraClip system assisted by ICE is feasible in patients with prior surgical rings, achieving an excellent risk profile and satisfactory procedural success. © 2015 Wiley Periodicals, Inc.
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Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves
Weber, Miriam; Gonzalez de Torre, Israel; Moreira, Ricardo; Frese, Julia; Oedekoven, Caroline; Alonso, Matilde; Rodriguez Cabello, Carlos J.
2015-01-01
Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels. PMID:25654448
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Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves.
Weber, Miriam; Gonzalez de Torre, Israel; Moreira, Ricardo; Frese, Julia; Oedekoven, Caroline; Alonso, Matilde; Rodriguez Cabello, Carlos J; Jockenhoevel, Stefan; Mela, Petra
2015-08-01
Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels.
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Dickinson, Rebecca; Raynor, David K; Knapp, Peter; MacDonald, Jan
2017-04-01
Patient information leaflets (PILs) are required with all licensed medicines throughout the European Union (EU) and they must include information about all side effects and their likelihood. This has led to criticism of a lack of balance, with little information included about potential benefits. Recent European Medicines Agency guidance proposed the inclusion of benefit information, and this study examined the current prevalence and type of such information in PILs in the EU. A survey and content analysis of the English translation of PILs in the EUwas carried out. Random quota sampling was used on the most frequently dispensed (n = 50) and newly licensed medicines (n = 50) in 2011/2. Leaflets were searched for benefit information meeting predefined criteria, and data synthesised and categorised into 10 categories. Eighty-five (85%) leaflets described how the medicine works, with 45 providing information about the rationale for treatment (more commonly for newly licensed (32/50) than most commonly dispensed medicines (13/50; P < 0.001). Nearly half (47) did not describe whether the medicine was curative, symptomatic or preventative. The terms used to communicate uncertainty were imprecise (such as 'may help'). None communicated numerical benefit information. Current PILs do not appropriately communicate information about benefit. At the basic level, around a half did not include information about treatment rationale or whether the treatment was to treat symptoms, curative or preventative. However, for true informed decision making, patients need quantitative information about benefits and none of the leaflets provided this. © 2016 Royal Pharmaceutical Society.
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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…
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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…
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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...
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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,…
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How readable are Australian paediatric oral health education materials?
Arora, Amit; Lam, Andy S F; Karami, Zahra; Do, Loc Giang; Harris, Mark Fort
2014-09-02
The objective of this study was to analyse the readability of paediatric oral health education leaflets available in Australia. Forty paediatric oral health education materials were analysed for general readability according to the following parameters: Thoroughness; Textual framework; Terminology; and Readability (Flesch-Kincaid grade level (FKGL), Gunning Fog index (Fog) and Simplified Measure of Gobbledygook (SMOG)). Leaflets produced by the industry were among the hardest to read with an average readability at the 8th grade (8.4 ± 0.1). The readability of leaflets produced by the commercial sector was at the 7th grade (7.1 ± 1.7) and the government at the 6th grade (6.3 ± 1.9). The FKGL consistently yielded readabilities 2 grades below the Fog and SMOG indexes. In the content analyses, 14 essential paediatric oral health topics were noted and Early Childhood Caries (ECC) was identified as the most commonly used jargon term. Paediatric oral health education materials are readily available, yet their quality and readability vary widely and may be difficult to read for disadvantaged populations in Australia. A redesign of these leaflets while taking literacy into consideration is suggested.
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Kemmitt, Gregory M; DeBoer, Gerrit; Ouimette, David; Iamauti, Marilene
2008-12-01
The demethylation inhibitor (DMI) fungicide myclobutanil can be an effective component of spray programmes designed to control the highly destructive plant pathogen Phakopsora pachyrhizi Syd. & P. Syd., causal agent of Asian soybean rust. Myclobutanil is known from previous studies in grapevines to be xylem mobile. This study investigates the mobility profile of myclobutanil in soybean as an important component of its effective field performance. Over a 12 day period under greenhouse conditions, a constant uptake of myclobutanil from leaflet surfaces into the leaflet tissue was observed. Once in the leaflet, myclobutanil was seen to redistribute throughout the tissue, although no movement out of leaflets occurred owing to a lack of phloem mobility. The ability of myclobutanil to redistribute over distance within the soybean plant was revealed when visualizing movement of the compound to foliage above the point of application on the plant stem. An efficacy bioassay demonstrated that the systemic properties of myclobutanil allow control of disease at a point remote from the initial site of compound application. It is suggested that the high degree of xylem systemicity displayed by myclobutanil in soybean foliage is a contributory factor towards its commercial effectiveness for control of Asian soybean rust.
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Cholesterol asymmetry in synaptic plasma membranes.
Wood, W Gibson; Igbavboa, Urule; Müller, Walter E; Eckert, Gunter P
2011-03-01
Lipids are essential for the structural and functional integrity of membranes. Membrane lipids are not randomly distributed but are localized in different domains. A common characteristic of these membrane domains is their association with cholesterol. Lipid rafts and caveolae are examples of cholesterol enriched domains, which have attracted keen interest. However, two other important cholesterol domains are the exofacial and cytofacial leaflets of the plasma membrane. The two leaflets that make up the bilayer differ in their fluidity, electrical charge, lipid distribution, and active sites of certain proteins. The synaptic plasma membrane (SPM) cytofacial leaflet contains over 85% of the total SPM cholesterol as compared with the exofacial leaflet. This asymmetric distribution of cholesterol is not fixed or immobile but can be modified by different conditions in vivo: (i) chronic ethanol consumption; (ii) statins; (iii) aging; and (iv) apoE isoform. Several potential candidates have been proposed as mechanisms involved in regulation of SPM cholesterol asymmetry: apoE, low-density lipoprotein receptor, sterol carrier protein-2, fatty acid binding proteins, polyunsaturated fatty acids, P-glycoprotein and caveolin-1. This review examines cholesterol asymmetry in SPM, potential mechanisms of regulation and impact on membrane structure and function. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.
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NASA Astrophysics Data System (ADS)
Khan, Mahasin Ali; Bera, Subir
2016-07-01
Fossil leaflet impression described here as a new species Rourea miocaudata sp. nov., showing close resemblance with the modern leaflets of Rourea caudata Planch. (Connaraceae R. Br.), has been recorded from the lower part of the Siwalik sediments (Dafla Formation, middle-upper Miocene) exposed at the road-cutting section of Pinjoli area in West Kameng district, Arunachal Pradesh. The important morphological characters of the fossil are its narrow elliptic leaflet, cuneate base, long caudate apex, entire margin, eucamptodromous to brochidodromous secondary veins, presence of intersecondary veins, percurrent and reticulate tertiary veins and orthogonally reticulate quaternary veins. This is the first authentic record of the occurrence of leaflet comparable to R. caudata of Connaraceae from the Cenozoic sediments of India and abroad. At present R. caudata does not grow in India and is restricted only in southeast Asia especially in China and Myanmar. This taxon probably migrated to these southeast Asian regions after lower Siwalik sedimentation (middle-upper Miocene) due to climatic change caused by post-Miocene orogenic movement of the Himalaya. The recovery of this species and other earlier-described evergreen taxa from the same formation, suggests the existence of a tropical, warm and humid climatic conditions during the depositional period.
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Ryali, Srikanth; Chen, Tianwen; Li, Chiang-Shan R.
2014-01-01
The right inferior frontal cortex (rIFC) and the right anterior insula (rAI) have been implicated consistently in inhibitory control, but their differential roles are poorly understood. Here we use multiple quantitative techniques to dissociate the functional organization and roles of the rAI and rIFC. We first conducted a meta-analysis of 70 published inhibitory control studies to generate a commonly activated right fronto-opercular cortex volume of interest (VOI). We then segmented this VOI using two types of features: (1) intrinsic brain activity; and (2) stop-signal task-evoked hemodynamic response profiles. In both cases, segmentation algorithms identified two stable and distinct clusters encompassing the rAI and rIFC. The rAI and rIFC clusters exhibited several distinct functional characteristics. First, the rAI showed stronger intrinsic and task-evoked functional connectivity with the anterior cingulate cortex, whereas the rIFC had stronger intrinsic and task-evoked functional connectivity with dorsomedial prefrontal and lateral fronto-parietal cortices. Second, the rAI showed greater activation than the rIFC during Unsuccessful, but not Successful, Stop trials, and multivoxel response profiles in the rAI, but not the rIFC, accurately differentiated between Successful and Unsuccessful Stop trials. Third, activation in the rIFC, but not rAI, predicted individual differences in inhibitory control abilities. Crucially, these findings were replicated in two independent cohorts of human participants. Together, our findings provide novel quantitative evidence for the dissociable roles of the rAI and rIFC in inhibitory control. We suggest that the rAI is particularly important for detecting behaviorally salient events, whereas the rIFC is more involved in implementing inhibitory control. PMID:25355218
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The enigmatic fast leaflet rotation in Desmodium motorium
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
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Interaction between bending and tension forces in bilayer membranes.
Secomb, T W
1988-01-01
A theoretical analysis is presented of the bending mechanics of a membrane consisting of two tightly-coupled leaflets, each of which shears and bends readily but strongly resists area changes. Structures of this type have been proposed to model biological membranes such as red blood cell membrane. It is shown that when such a membrane is bent, anisotropic components of resultant membrane tension (shear stresses) are induced, even when the tension in each leaflet is isotropic. The induced shear stresses increase as the square of the membrane curvature, and become significant for moderate curvatures (when the radius of curvature is much larger than the distance between the leaflets). This effect has implications for the analysis of shape and deformation of freely suspended and flowing red blood cells. PMID:3224154
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A Ruptured Mitral Valve Aneurysm as Complication of a Bicuspid Aortic Valve Endocarditis.
Muscente, Francesca; Scarano, Michele; Clemente, Daniela; Pezzuoli, Franco; Parato, Vito Maurizio
2017-01-01
We present a case of a ruptured mitral valve (MV) aneurysm as a complication of a bicuspid aortic valve (BAV) endocarditis. It is about a young 35-year-old man, admitted to Cardiology Unit because of unexpected heart failure picture. We found a BAV endocarditis complicated by anterior MV-anterior leaflet aneurysm formation and subsequent severe MV regurgitation caused by aneurysm perforation. It was a particular and rare situation characterized by an infection of anterior mitral leaflet secondary to an infected regurgitant jet of a primary aortic infective endocarditis due to a BAV. A resulting aneurysm formation on the atrial side of the mitral anterior leaflet leads later to mitral perforation. In this article, we review the more relevant medical literature on this topic.
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Repair for mitral stenosis due to pannus formation after Duran ring annuloplasty.
Song, Seunghwan; Cho, Seong Ho; Yang, Ji-Hyuk; Park, Pyo Won
2010-12-01
Mitral stenosis after mitral repair with using an annuloplasty ring is not common and it is almost always due to pannus formation. Mitral valve replacement was required in most of the previous cases of pannus covering the mitral valve leaflet, which could not be stripped off without damaging the valve leaflets. In two cases, we removed the previous annuloplasty ring and pannus without leaflet injury, and we successfully repaired the mitral valve. During the follow-up of 4 months and 39 months respectively, we observed improvement of the patients' symptoms and good valvular function. Redo mitral repair may be a possible method for treating mitral stenosis due to pannus formation after ring annuloplasty. Copyright © 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
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The enigmatic fast leaflet rotation in Desmodium motorium: butterfly mimicry for defense?
Lev-Yadun, Simcha
2013-06-01
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.
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Pathophysiology of Degenerative Mitral Regurgitation: New 3-Dimensional Imaging Insights.
Antoine, Clemence; Mantovani, Francesca; Benfari, Giovanni; Mankad, Sunil V; Maalouf, Joseph F; Michelena, Hector I; Enriquez-Sarano, Maurice
2018-01-01
Despite its high prevalence, little is known about mechanisms of mitral regurgitation in degenerative mitral valve disease apart from the leaflet prolapse itself. Mitral valve is a complex structure, including mitral annulus, mitral leaflets, papillary muscles, chords, and left ventricular walls. All these structures are involved in physiological and pathological functioning of this valvuloventricular complex but up to now were difficult to analyze because of inherent limitations of 2-dimensional imaging. The advent of 3-dimensional echocardiography, computed tomography, and cardiac magnetic resonance imaging overcoming these limitations provides new insights into mechanistic analysis of degenerative mitral regurgitation. This review will detail the contribution of quantitative and qualitative dynamic analysis of mitral annulus and mitral leaflets by new imaging methods in the understanding of degenerative mitral regurgitation pathophysiology. © 2018 American Heart Association, Inc.
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Selective Reduction: "A Soft Cover for Hard Choices" or Another Name for Abortion?
Rao, Radhika
2015-01-01
Selective reduction and abortion both involve the termination of fetal life, but they are classified by different designations to underscore the notion that they are regarded as fundamentally different medical procedures: the two are performed using distinct techniques by different types of physicians, upon women under very different circumstances, in order to further dramatically different objectives. Hence, the two procedures appear to call for a distinct moral calculus, and they have traditionally evoked contradictory reactions from society. This essay posits that despite their different appellations, selective reduction and abortion are essentially equivalent. © 2015 American Society of Law, Medicine & Ethics, Inc.
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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 closing process. After the valve was fully closed, local flow activities in the proximity of the valve region persisted for a certain time before slowly dying out. In both the valve opening and closing processes, maximum velocity always appeared near the leaflet trailing edges. The flow field features revealed in the present paper improved our understanding of valve motion mechanism under physiological conditions, and this knowledge is very helpful in designing the new generation of MHVs.
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Development of an off bypass mitral valve repair.
Morales, D L; Madigan, J D; Choudhri, A F; Williams, M R; Helman, D N; Elder, J B; Naka, Y; Oz, M C
1999-01-01
The Bow Tie Repair (BTR), a single edge-to-edge suture opposing the anterior and posterior leaflets of the mitral valve (MV), has led to satisfactory reduction of mitral regurgitation (MR) with few re-operations and excellent hemodynamic results. The simplicity of the repair lends itself to minimally invasive approaches. A MV grasper has been developed that will coapt both leaflets and fasten the structures with a graduated spiral screw. Eleven explanted adult human MVs were mounted in a mock circulatory loop created for simulating a variety of hemodynamic conditions. The MV grasper was used to place a screw in each valve, which was then continuously run for 300,000 to 1,000,000 cycles with a fixed transvalvular pressure gradient. At the completion of these studies, the valves were stressed to a maximal transvalvular gradient for ten minutes. In seven cases, MR was induced and subsequently repaired using the MV screw. In vivo, the MV screw was tested in nine male canines. Through a subcostal incision, the MV grasper entered the left ventricle, approximated the mitral leaflets and deployed the MV screw under direct visualization via an atriotomy. Follow-up transthoracic echocardiograms were done at postoperative week 1, 6, and 12 to identify screw migration, MV regurgitation/stenosis or clot formation. Dogs were sacrificed up to postoperative week 12 to allow gross and histologic assessment. In vitro, no MV screw detached from the valve leaflets or migrated during the durability testing period of 6.8 million cycles, including periods of stress load testing up to 350 mm Hg. The percent regurgitant flow used to assess MR statistically decreased with the placement of the screw from 72 +/- 7% to 34 +/- 17%; p = 0.0025. In vivo, seven dogs whose valves were examined within the first 48 hours revealed leaflet coaptation with an intact MV screw and no evidence of MR. Two dogs, followed for a prolonged period, had serial postoperative echocardiograms demonstrating consistent coaptation, no screw migration, no clot, and no regurgitation or stenosis. In the animal sacrificed at 12 weeks, the MV screw was integrated into the tissue of both leaflets. The MV screw has provided durable leaflet coaptation and has reduced regurgitation in human MVs. Initial data on the MV screw's biocompatibility and interactions with living valve tissue is promising. Our early success supports further efforts towards the maturation of this prototype into off bypass mitral valve repair technology.
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Nikulin, Vadim V; Linkenkaer-Hansen, Klaus; Nolte, Guido; Curio, Gabriel
2010-02-01
The aim of the present study was to show analytically and with simulations that it is the non-zero mean of neuronal oscillations, and not an amplitude asymmetry of peaks and troughs, that is a prerequisite for the generation of evoked responses through a mechanism of amplitude modulation of oscillations. Secondly, we detail the rationale and implementation of the "baseline-shift index" (BSI) for deducing whether empirical oscillations have non-zero mean. Finally, we illustrate with empirical data why the "amplitude fluctuation asymmetry" (AFA) index should be used with caution in research aimed at explaining variability in evoked responses through a mechanism of amplitude modulation of ongoing oscillations. An analytical approach, simulations and empirical MEG data were used to compare the specificity of BSI and AFA index to differentiate between a non-zero mean and a non-sinusoidal shape of neuronal oscillations. Both the BSI and the AFA index were sensitive to the presence of non-zero mean in neuronal oscillations. The AFA index, however, was also sensitive to the shape of oscillations even when they had a zero mean. Our findings indicate that it is the non-zero mean of neuronal oscillations, and not an amplitude asymmetry of peaks and troughs, that is a prerequisite for the generation of evoked responses through a mechanism of amplitude modulation of oscillations. A clear distinction should be made between the shape and non-zero mean properties of neuronal oscillations. This is because only the latter contributes to evoked responses, whereas the former does not. Copyright (c) 2009 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
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Roles of TRPV1 and TRPA1 in Spontaneous Pain from Inflamed Masseter Muscle.
Wang, Sheng; Brigoli, Benjamin; Lim, Jongseuk; Karley, Alisha; Chung, Man-Kyo
2018-06-08
Craniofacial muscle pain, such as spontaneous pain and bite-evoked pain, are major symptoms in patients with temporomandibular disorders and infection. However, the underlying mechanisms of muscle pain, especially mechanisms of highly prevalent spontaneous pain, are poorly understood. Recently, we reported that transient receptor potential vanilloid 1 (TRPV1) contributes to spontaneous pain but only marginally contributes to bite-evoked pain during masseter inflammation. Here, we investigated the role of transient receptor potential ankyrin 1 (TRPA1) in spontaneous and bite-evoked pain during masseter inflammation, and dissected the relative contributions of TRPA1 and TRPV1. Masseter inflammation increased mouse grimace scale (MGS) scores and face wiping behaviors. Pharmacological or genetic inhibition of TRPA1 significantly attenuated MGS but not face wiping behaviors. MGS scores were also attenuated by scavenging putative endogenous ligands for TRPV1 or TRPA1. Simultaneous inhibition of TRPA1 by AP18 and TRPV1 by AMG9810 in masseter muscle resulted in robust inhibition of both MGS and face wiping behaviors. Administration of AP18 or AMG9810 to masseter muscle induced conditioned place preference (CPP). The extent of CPP following simultaneous administration of AP18 and AMG9810 was greater than that induced by the individual antagonists. In contrast, inflammation-induced reduction of bite force was not affected by the inhibition of TRPA1 alone or in combination with TRPV1. These results suggest that simultaneous inhibition of TRPV1 and TRPA1 produces additive relief of spontaneous pain, but does not ameliorate bite-evoked pain during masseter inflammation. Our results provide further evidence that distinct mechanisms underlie spontaneous and bite-evoked pain from inflamed masseter muscle. Copyright © 2018. Published by Elsevier Ltd.
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ERIC Educational Resources Information Center
Owens, Christabel; Charles, Nigel
2017-01-01
Objectives: Significant others can play a key role in suicide prevention, but little attention has been given to the resources they may need in order to do so effectively. Based on previous qualitative research and working in partnership with suicide prevention charities, we developed a simple educational leaflet to help family members and friends…
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Beaujean, D J M A; Gassner, F; Wong, A; Steenbergen, J E; Crutzen, R; Ruwaard, D
2016-11-16
Lyme disease or Lyme borreliosis (LB) is the most common tick-borne disease both in the United States and Europe. Children, in particular, are at high risk of contracting LB. Since child-specific educational tools on ticks, tick bites and LB are lacking, we developed an online educational video game. In this study, we compared the effectiveness of an online educational video game versus a newly developed leaflet aimed to improve prevention of tick bites and LB among Dutch schoolchildren. A total of 887 children, aged 9-13 years and attending the two final years of primary schooling, were recruited from 25 primary schools in June and July 2012. They were assigned through cluster randomization to one of three intervention groups: 'game' (22.4%), 'leaflet' (35.6%) or 'control' (41.9%). Prior to and directly following intervention, the children were asked to complete a short questionnaire. The main outcome measures were knowledge, perception (perceived susceptibility and importance) and preventive behavior in relation to tick bites and LB. Generalized linear mixed models were used to analyze the data. In the game group, the leaflet group and the control group, knowledge about ticks and tick bites improved significantly. The game was also an effective tool for improving preventive behavior; the frequency of checking for ticks increased significantly. However, there were no significant differences in knowledge improvement between the interventions. The game outperformed the leaflet in terms of improving preventive behavior, whereas the frequency of tick checks increased significantly. But this frequency didn't increase more than in the control group. The positive knowledge effects observed in the control group suggests the presence of a mere measurement effect related to completion of the questionnaire. The game did not outperform the leaflet or control group on all outcome measures. Therefore, the game may be of value as a complementary role, in addition to other media, in child-specific public health education programs on ticks and LB. This trial was retrospectively registered on October 21, 2016 (trial registration number: ISRCTN15142369).
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Effect of Losartan on Mitral Valve Changes After Myocardial Infarction.
Bartko, Philipp E; Dal-Bianco, Jacob P; Guerrero, J Luis; Beaudoin, Jonathan; Szymanski, Catherine; Kim, Dae-Hee; Seybolt, Margo M; Handschumacher, Mark D; Sullivan, Suzanne; Garcia, Michael L; Titus, James S; Wylie-Sears, Jill; Irvin, Whitney S; Messas, Emmanuel; Hagège, Albert A; Carpentier, Alain; Aikawa, Elena; Bischoff, Joyce; Levine, Robert A
2017-09-05
After myocardial infarction (MI), mitral valve (MV) tethering stimulates adaptive leaflet growth, but counterproductive leaflet thickening and fibrosis augment mitral regurgitation (MR), doubling heart failure and mortality. MV fibrosis post-MI is associated with excessive endothelial-to-mesenchymal transition (EMT), driven by transforming growth factor (TGF)-β overexpression. In vitro, losartan-mediated TGF-β inhibition reduces EMT of MV endothelial cells. This study tested the hypothesis that profibrotic MV changes post-MI are therapeutically accessible, specifically by losartan-mediated TGF-β inhibition. The study assessed 17 sheep, including 6 sham-operated control animals and 11 with apical MI and papillary muscle retraction short of producing MR; 6 of the 11 were treated with daily losartan, and 5 were untreated, with flexible epicardial mesh comparably limiting left ventricular (LV) remodeling. LV volumes, tethering, and MV area were quantified by using three-dimensional echocardiography at baseline and at 60 ± 6 days, and excised leaflets were analyzed by histopathology and flow cytometry. Post-MI LV dilation and tethering were comparable in the losartan-treated and untreated LV constraint sheep. Telemetered sensors (n = 6) showed no significant losartan-induced changes in arterial pressure. Losartan strongly reduced leaflet thickness (0.9 ± 0.2 mm vs. 1.6 ± 0.2 mm; p < 0.05; 0.4 ± 0.1 mm sham animals), TGF-β, and downstream phosphorylated extracellular-signal-regulated kinase and EMT (27.2 ± 12.0% vs. 51.6 ± 11.7% α-smooth muscle actin-positive endothelial cells, p < 0.05; 7.2 ± 3.5% sham animals), cellular proliferation, collagen deposition, endothelial cell activation (vascular cell adhesion molecule-1 expression), neovascularization, and cells positive for cluster of differentiation (CD) 45, a hematopoietic marker associated with post-MI valve fibrosis. Leaflet area increased comparably (17%) in constrained and losartan-treated sheep. Profibrotic changes of tethered MV leaflets post-MI can be modulated by losartan without eliminating adaptive growth. Understanding the cellular and molecular mechanisms could provide new opportunities to reduce ischemic MR. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
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Rabbah, Jean-Pierre; Saikrishnan, Neelakantan; Yoganathan, Ajit P
2013-02-01
Numerical models of the mitral valve have been used to elucidate mitral valve function and mechanics. These models have evolved from simple two-dimensional approximations to complex three-dimensional fully coupled fluid structure interaction models. However, to date these models lack direct one-to-one experimental validation. As computational solvers vary considerably, experimental benchmark data are critically important to ensure model accuracy. In this study, a novel left heart simulator was designed specifically for the validation of numerical mitral valve models. Several distinct experimental techniques were collectively performed to resolve mitral valve geometry and hemodynamics. In particular, micro-computed tomography was used to obtain accurate and high-resolution (39 μm voxel) native valvular anatomy, which included the mitral leaflets, chordae tendinae, and papillary muscles. Three-dimensional echocardiography was used to obtain systolic leaflet geometry. Stereoscopic digital particle image velocimetry provided all three components of fluid velocity through the mitral valve, resolved every 25 ms in the cardiac cycle. A strong central filling jet (V ~ 0.6 m/s) was observed during peak systole with minimal out-of-plane velocities. In addition, physiologic hemodynamic boundary conditions were defined and all data were synchronously acquired through a central trigger. Finally, the simulator is a precisely controlled environment, in which flow conditions and geometry can be systematically prescribed and resultant valvular function and hemodynamics assessed. Thus, this work represents the first comprehensive database of high fidelity experimental data, critical for extensive validation of mitral valve fluid structure interaction simulations.
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Rajasekharan, Archita; Gummadi, Sathyanarayana N.
2011-01-01
Eukaryotic cells are compartmentalized into distinct sub-cellular organelles by lipid bilayers, which are known to be involved in numerous cellular processes. The wide repertoire of lipids, synthesized in the biogenic membranes like the endoplasmic reticulum and bacterial cytoplasmic membranes are initially localized in the cytosolic leaflet and some of these lipids have to be translocated to the exoplasmic leaflet for membrane biogenesis and uniform growth. It is known that phospholipid (PL) translocation in biogenic membranes is mediated by specific membrane proteins which occur in a rapid, bi-directional fashion without metabolic energy requirement and with no specificity to PL head group. A recent study reported the existence of biogenic membrane flippases in plants and that the mechanism of plant membrane biogenesis was similar to that found in animals. In this study, we demonstrate for the first time ATP independent and ATP dependent flippase activity in chloroplast membranes of plants. For this, we generated proteoliposomes from Triton X-100 extract of intact chloroplast, envelope membrane and thylakoid isolated from spinach leaves and assayed for flippase activity using fluorescent labeled phospholipids. Half-life time of flipping was found to be 6±1 min. We also show that: (a) intact chloroplast and envelope membrane reconstituted proteoliposomes can flip fluorescent labeled analogs of phosphatidylcholine in ATP independent manner, (b) envelope membrane and thylakoid reconstituted proteoliposomes can flip phosphatidylglycerol in ATP dependent manner, (c) Biogenic membrane ATP independent PC flipping activity is protein mediated and (d) the kinetics of PC translocation gets affected differently upon treatment with protease and protein modifying reagents. PMID:22174798
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Rajasekharan, Archita; Gummadi, Sathyanarayana N
2011-01-01
Eukaryotic cells are compartmentalized into distinct sub-cellular organelles by lipid bilayers, which are known to be involved in numerous cellular processes. The wide repertoire of lipids, synthesized in the biogenic membranes like the endoplasmic reticulum and bacterial cytoplasmic membranes are initially localized in the cytosolic leaflet and some of these lipids have to be translocated to the exoplasmic leaflet for membrane biogenesis and uniform growth. It is known that phospholipid (PL) translocation in biogenic membranes is mediated by specific membrane proteins which occur in a rapid, bi-directional fashion without metabolic energy requirement and with no specificity to PL head group. A recent study reported the existence of biogenic membrane flippases in plants and that the mechanism of plant membrane biogenesis was similar to that found in animals. In this study, we demonstrate for the first time ATP independent and ATP dependent flippase activity in chloroplast membranes of plants. For this, we generated proteoliposomes from Triton X-100 extract of intact chloroplast, envelope membrane and thylakoid isolated from spinach leaves and assayed for flippase activity using fluorescent labeled phospholipids. Half-life time of flipping was found to be 6 ± 1 min. We also show that: (a) intact chloroplast and envelope membrane reconstituted proteoliposomes can flip fluorescent labeled analogs of phosphatidylcholine in ATP independent manner, (b) envelope membrane and thylakoid reconstituted proteoliposomes can flip phosphatidylglycerol in ATP dependent manner, (c) Biogenic membrane ATP independent PC flipping activity is protein mediated and (d) the kinetics of PC translocation gets affected differently upon treatment with protease and protein modifying reagents.
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Readability of medicinal package leaflets: a systematic review
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. PMID:25741660
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2013-01-01
Background Adolescent girls are at an age to be involved in the decision about HPV vaccination uptake and therefore need adequate information about the vaccination. This study assesses to what extent reading an official information leaflet about HPV contributes to girls’ knowledge levels, and to what extent an increase in knowledge is boosted by a pre-test measurement. Methods Participants (girls aged 11–14 years) were systematically allocated to group A that completed a pre-test measurement (12 true/false statements) or to group B that did not complete it. Subsequently, both groups read the HPV leaflet and completed the post-test measurement. Results The response rate was 237/287 (83%). Pre-test scores in group A (M = 3.6, SD = 1.81, p < 0.001) were lower than post-test mean knowledge scores (0–10) in group B (M = 4.6, SD = 2.05). Post-test knowledge scores in group A were higher than those in group B [6.2 (SD = 2.06) versus 4.6 (SD = 2.05), p < 0.001]. In the post-test measurement, about a third of both groups knew that vaccinations do not give 100% protection against cervical cancer and that the duration of protection is unknown. Conclusions Reading the information leaflet had a positive effect on knowledge, even more so when boosted by a pre-test measurement. However, knowledge on the degree and duration of protection against cervical cancer remained limited. Focusing girls’ attention on important aspects before they start reading the leaflet (e.g. by including a quiz on the first page) may serve to raise their awareness of these aspects. PMID:23802703
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Movva, Rajesh; Murthy, Kinnari; Romero-Corral, Abel; Seetha Rammohan, Harish Raj; Fumo, Peter; Pressman, Gregg S
2013-10-01
Mitral annular calcification (MAC) is common in chronic kidney disease. It is associated with cardiovascular events and can cause valvular dysfunction, but it has not been systematically characterized. The aim of this prospective study was to assess the prevalence and distribution of MAC, its effects on leaflet motion, and its association with mitral stenosis and mitral regurgitation (MR) in a hemodialysis population. Echocardiograms were obtained in 75 consecutive hemodialysis outpatients. MAC extent and distribution were graded semiquantitatively using two-dimensional and three-dimensional echocardiography. Associations with the presence and severity of mitral stenosis and MR were explored. The mean age was 60 ± 14 years; 60% were men, and 87% were African American. MAC was present in 64% (moderate to severe in 48%). Calcium extended more than halfway onto the leaflet in 37% and beyond the annulus in 40%. Leaflet motion was restricted in 37%. Mitral stenosis was present in 28%, and the extent of calcification was associated with mean mitral valve gradient (P < .0001). MR was prevalent (present in 81%) but was severe in none. The severity of MAC was greater in patients with moderate MR than in those with no or mild MR (P = .04). Three-dimensional analysis suggested an uneven distribution of annular calcium; the middle and lateral anterior segments were less often calcified than the anterior-medial or posterior segments. Calcification in any annular segment was highly associated with restricted motion of the attached leaflet segment. MAC is common and often extensive in hemodialysis patients. Calcium may be unevenly distributed among the annular segments. When present, annular calcification reduces the angle of leaflet opening and can cause valvular dysfunction. Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.
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Fast image-based mitral valve simulation from individualized geometry.
Villard, Pierre-Frederic; Hammer, Peter E; Perrin, Douglas P; Del Nido, Pedro J; Howe, Robert D
2018-04-01
Common surgical procedures on the mitral valve of the heart include modifications to the chordae tendineae. Such interventions are used when there is extensive leaflet prolapse caused by chordae rupture or elongation. Understanding the role of individual chordae tendineae before operating could be helpful to predict whether the mitral valve will be competent at peak systole. Biomechanical modelling and simulation can achieve this goal. We present a method to semi-automatically build a computational model of a mitral valve from micro CT (computed tomography) scans: after manually picking chordae fiducial points, the leaflets are segmented and the boundary conditions as well as the loading conditions are automatically defined. Fast finite element method (FEM) simulation is carried out using Simulation Open Framework Architecture (SOFA) to reproduce leaflet closure at peak systole. We develop three metrics to evaluate simulation results: (i) point-to-surface error with the ground truth reference extracted from the CT image, (ii) coaptation surface area of the leaflets and (iii) an indication of whether the simulated closed leaflets leak. We validate our method on three explanted porcine hearts and show that our model predicts the closed valve surface with point-to-surface error of approximately 1 mm, a reasonable coaptation surface area, and absence of any leak at peak systole (maximum closed pressure). We also evaluate the sensitivity of our model to changes in various parameters (tissue elasticity, mesh accuracy, and the transformation matrix used for CT scan registration). We also measure the influence of the positions of the chordae tendineae on simulation results and show that marginal chordae have a greater influence on the final shape than intermediate chordae. The mitral valve simulation can help the surgeon understand valve behaviour and anticipate the outcome of a procedure. Copyright © 2018 John Wiley & Sons, Ltd.
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Hofman, Robine; Schiffers, Puck A W H; Richardus, Jan Hendrik; Raat, Hein; de Kok, Inge M C M; van Ballegooijen, Marjolein; Korfage, Ida J
2013-06-26
Adolescent girls are at an age to be involved in the decision about HPV vaccination uptake and therefore need adequate information about the vaccination. This study assesses to what extent reading an official information leaflet about HPV contributes to girls' knowledge levels, and to what extent an increase in knowledge is boosted by a pre-test measurement. Participants (girls aged 11-14 years) were systematically allocated to group A that completed a pre-test measurement (12 true/false statements) or to group B that did not complete it. Subsequently, both groups read the HPV leaflet and completed the post-test measurement. The response rate was 237/287 (83%). Pre-test scores in group A (M = 3.6, SD = 1.81, p < 0.001) were lower than post-test mean knowledge scores (0-10) in group B (M = 4.6, SD = 2.05). Post-test knowledge scores in group A were higher than those in group B [6.2 (SD = 2.06) versus 4.6 (SD = 2.05), p < 0.001]. In the post-test measurement, about a third of both groups knew that vaccinations do not give 100% protection against cervical cancer and that the duration of protection is unknown. Reading the information leaflet had a positive effect on knowledge, even more so when boosted by a pre-test measurement. However, knowledge on the degree and duration of protection against cervical cancer remained limited. Focusing girls' attention on important aspects before they start reading the leaflet (e.g. by including a quiz on the first page) may serve to raise their awareness of these aspects.
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Marsit, Ons; Royer, Olivier; Drolet, Marie-Claude; Arsenault, Marie; Couet, Jacques; Morin, Stéphane; Levine, Robert A; Pibarot, Philippe; Beaudoin, Jonathan
2017-05-01
Mitral leaflet enlargement in patients with chronic aortic regurgitation (AR) has been identified as an adaptive mechanism potentially able to prevent functional mitral regurgitation (FMR) in response to left ventricular (LV) dilatation. The timing of valve enlargement is not known, and the related mechanisms are largely unexplored. AR was induced in 58 rats, and another 54 were used as sham controls. Animals were euthanized at different time points after AR creation (48 h, one week, and three months), and AR severity, FMR and LV dilatation were assessed using echocardiography. Mitral valves were harvested to document the reactivation of embryonic growth pathways. AR animals had increased LV dimensions and mitral annulus size. No animal developed FMR. No change in leaflet length or thickness was seen at 48 h; however, anterior mitral leaflets were longer and thicker in AR animals at one week and three months. Molecular changes were present early (at 48 h and at one week), with positive staining for transforming growth factor-b1 (TGF-b1), Alpha-smooth muscle actin (α-SMA) and matrix metalloproteinase-2 (MMP-2), which suggested active matrix remodeling. Increased gene expression for collagen 1, TGF-β1, α-SMA and MMP-2 was found in the mitral valve at 48 h and at one week, but after three months their expression had returned to normal. This model of AR induces active expansion and thickening of the mitral leaflets. Growth signals are expressed acutely, but not at three months, which suggests that most of this enlargement occurs at an early stage. The stimulation of valvular growth could represent a new strategy for the prevention of FMR.
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Morant, Kareem; Mikami, Yoko; Nevis, Immaculate; McCarty, David; Stirrat, John; Scholl, David; Rajchl, Martin; Giannoccaro, Peter; Kolman, Louis; Heydari, Bobby; Lydell, Carmen; Howarth, Andrew; Grant, Andrew; White, James A
2017-08-01
We sought to examine whether elongation of the mitral valve leaflets in patients with hypertrophic cardiomyopathy (HCM) is synergistic to septal wall thickness (SWT) in the development of left ventricular outflow tract obstruction (LVOTO). HCM is a common genetic cardiac disease characterized by asymmetric septal hypertrophy and predisposition towards LVOTO. It has been reported that elongation of the mitral valve leaflets may be a primary phenotypic feature and contribute to LVOTO. However, the relative contribution of this finding versus SWT has not been studied. 152 patients (76 with HCM and 76 non-diseased age, race and BSA-matched controls) and 18 young, healthy volunteers were studied. SWT and the anterior mitral valve leaflet length (AMVLL) were measured using cine MRI. The combined contribution of these variables (SWT × AMVLL) was described as the Septal Anterior Leaflet Product (SALP). Peak LVOT pressure gradient was determined by Doppler interrogation and defined as "obstructive" if ≥ 30 mmHg. Patients with HCM were confirmed to have increased AMVLL compared with controls and volunteers (p < 0.01). Among HCM patients, both SWT and SALP were significantly higher in patients with LVOTO (N = 17) versus without. SALP showed modest improvement in predictive accuracy for LVOTO (AUC = 0.81) among the HCM population versus SWT alone (AUC = 0.77). However, in isolated patients this variable identified patients with LVOTO despite modest SWT. Elongation of the AMVLL is a primary phenotypic feature of HCM. While incremental contributions to LVOTO appear modest at a population level, specific patients may have dominant contribution to LVOTO. The combined marker of SALP allows for maintained identification of such patients despite modest increases in SWT.
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Afilalo, Jonathan; Grapsa, Julia; Nihoyannopoulos, Petros; Beaudoin, Jonathan; Gibbs, J Simon R; Channick, Richard N; Langleben, David; Rudski, Lawrence G; Hua, Lanqi; Handschumacher, Mark D; Picard, Michael H; Levine, Robert A
2015-05-01
Tricuspid regurgitation (TR) is a risk factor for mortality in pulmonary hypertension (PH). TR severity varies among patients with comparable degrees of PH and right ventricular remodeling. The contribution of leaflet adaptation to the pathophysiology of TR has yet to be examined. We hypothesized that tricuspid leaflet area (TLA) is increased in PH, and that the adequacy of this increase relative to right ventricular remodeling determines TR severity. A prospective cohort of 255 patients with PH from pre and postcapillary pathogeneses was assembled from 2 centers. Patients underwent a 3-dimensional echocardiogram focused on the tricuspid apparatus. TLA was measured with the Omni 4D software package. Compared with normal controls, patients with PH had a 2-fold increase in right ventricular volumes, 62% increase in annular area, and 49% increase in TLA. Those with severe TR demonstrated inadequate increase in TLA relative to the closure area, such that the ratio of TLA:closure area <1.78 was highly predictive of severe TR (odds ratio, 68.7; 95% confidence interval, 16.2-292.7). The median vena contracta width was 8.5 mm in the group with small TLA and large closure area as opposed to 4.8 mm in the group with large TLA and large closure area. TLA plays a significant role in determining which patients with PH develop severe functional TR. The ratio of TLA:closure area, reflecting the balance between leaflet adaptation versus annular dilation and tethering forces, is an indicator of TR severity that may identify which patients stand to benefit from leaflet augmentation during tricuspid valve repair. © 2015 American Heart Association, Inc.
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Correction of anterior mitral prolapse: the parachute technique.
Zannis, Konstantinos; Mitchell-Heggs, Laurens; Di Nitto, Valentina; Kirsch, Matthias E W; Noghin, Milena; Ghorayeb, Gabriel; Lessana, Arrigo
2012-04-01
To evaluate a new surgical technique for the correction of anterior mitral leaflet prolapse. From October 2006 to November 2011, 44 consecutive patients (28 males, mean age 55 ± 13 years) underwent mitral valve repair because of anterior mitral leaflet prolapse. Echocardiography was performed to evaluate the distance from the tip of each papillary muscle to the annular plane. A specially designed caliper was used to manufacture a parachute-like device, by looping a 4-0 polytetrafluoroethylene suture between a Dacron strip and Teflon felt pledget, according to the preoperative echocardiographic measurements. This parachute was then used to resuspend the anterior mitral leaflet to the corresponding papillary muscle. Of the 44 patients, 35 (80%) required concomitant posterior leaflet repair. Additional procedures were required in 16 patients (36%). The preoperative logistic European System for Cardiac Operative Risk Evaluation was 4.3 ± 6.9. The clinical and echocardiographic follow-up were complete. The total follow-up was 1031 patient-months and averaged 23.4 ± 17.2 months per patient. The overall mortality rate was 4.5% (n = 2). Also, 2 patients (4.5%) with recurrent mitral regurgitation required mitral valve replacement, 1 on the first postoperative day and 1 after 13 months. In the latter patient, histologic analysis showed complete endothelialization of the Dacron strip. At follow-up, all non-reoperated survivors (n = 40) were in New York Heart Association class I, with no regurgitation in 40 patients (93%) and grade 2+ mitral regurgitation in 3 (7%). This technique offers a simple and reproducible solution for correction of anterior leaflet prolapse. Echocardiography can reliably evaluate the length of the chordae. However, the long-term results must be evaluated and compared with other surgical strategies. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.
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Traumatic Tricuspid Regurgitation.
Cheng, Yan; Yao, Lei; Wu, Shengjun
2017-05-31
Traumatic tricuspid regurgitation is a rare and progressive disease. Early diagnosis and surgical valve repair are very important. A 57-year-old male was referred to our hospital with a history of blunt chest trauma. Three-dimensional echocardiography showed severe tricuspid regurgitation and demonstrated two main anterior leaflet chordaes of the tricuspid valve rupture and the whole anterior leaflet prolapsed. The diagnosis was severe tricuspid regurgitation due to leaflet chordae rupture secondary to blunt chest trauma. Surgical repair of the tricuspid valve was performed in this patient. At 3-month follow-up, the right ventricle was decreased in size with significantly improved right ventricular function. The signs and symptoms of right heart failure were relieved. In this case, 3-dimensional transthoracic echocardiography enabled fast and non-invasive evaluation of the spatial destruction of the tricuspid valve and subvalvular apparatus to assist in the planning of valve repair.
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Pulmonary artery dissection following balloon valvuloplasty in a dog with pulmonic stenosis.
Grint, K A; Kellihan, H B
2017-04-01
A 3-month-old, 9.9 kg, male pit bull cross was referred for evaluation of collapse. A left basilar systolic heart murmur graded V/VI and a grade IV/VI right basilar systolic heart murmur were ausculted. Echocardiography showed severe pulmonic stenosis characterized by annular hypoplasia, leaflet thickening, and leaflet fusion. After 1 month of atenolol therapy, a pulmonic valve balloon valvuloplasty procedure was performed, and the intra-operative right ventricular pressure was reduced by 43%. Echocardiography, performed the following day, showed apparent rupture of a pulmonary valve leaflet and a membranous structure within the pulmonary artery consistent with a dissecting membrane. Short-term follow-up has shown no apparent progression of the pulmonary artery dissection and the patient remains free of clinical signs. Copyright © 2016 Elsevier B.V. All rights reserved.
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Engineering monolayer poration for rapid exfoliation of microbial membranes.
Pyne, Alice; Pfeil, Marc-Philipp; Bennett, Isabel; Ravi, Jascindra; Iavicoli, Patrizia; Lamarre, Baptiste; Roethke, Anita; Ray, Santanu; Jiang, Haibo; Bella, Angelo; Reisinger, Bernd; Yin, Daniel; Little, Benjamin; Muñoz-García, Juan C; Cerasoli, Eleonora; Judge, Peter J; Faruqui, Nilofar; Calzolai, Luigi; Henrion, Andre; Martyna, Glenn J; Grovenor, Chris R M; Crain, Jason; Hoogenboom, Bart W; Watts, Anthony; Ryadnov, Maxim G
2017-02-01
The spread of bacterial resistance to traditional antibiotics continues to stimulate the search for alternative antimicrobial strategies. All forms of life, from bacteria to humans, are postulated to rely on a fundamental host defense mechanism, which exploits the formation of open pores in microbial phospholipid bilayers. Here we predict that transmembrane poration is not necessary for antimicrobial activity and reveal a distinct poration mechanism that targets the outer leaflet of phospholipid bilayers. Using a combination of molecular-scale and real-time imaging, spectroscopy and spectrometry approaches, we introduce a structural motif with a universal insertion mode in reconstituted membranes and live bacteria. We demonstrate that this motif rapidly assembles into monolayer pits that coalesce during progressive membrane exfoliation, leading to bacterial cell death within minutes. The findings offer a new physical basis for designing effective antibiotics.
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Control of cerebellar granule cell output by sensory-evoked Golgi cell inhibition
Duguid, Ian; Branco, Tiago; Chadderton, Paul; Arlt, Charlotte; Powell, Kate; Häusser, Michael
2015-01-01
Classical feed-forward inhibition involves an excitation–inhibition sequence that enhances the temporal precision of neuronal responses by narrowing the window for synaptic integration. In the input layer of the cerebellum, feed-forward inhibition is thought to preserve the temporal fidelity of granule cell spikes during mossy fiber stimulation. Although this classical feed-forward inhibitory circuit has been demonstrated in vitro, the extent to which inhibition shapes granule cell sensory responses in vivo remains unresolved. Here we combined whole-cell patch-clamp recordings in vivo and dynamic clamp recordings in vitro to directly assess the impact of Golgi cell inhibition on sensory information transmission in the granule cell layer of the cerebellum. We show that the majority of granule cells in Crus II of the cerebrocerebellum receive sensory-evoked phasic and spillover inhibition prior to mossy fiber excitation. This preceding inhibition reduces granule cell excitability and sensory-evoked spike precision, but enhances sensory response reproducibility across the granule cell population. Our findings suggest that neighboring granule cells and Golgi cells can receive segregated and functionally distinct mossy fiber inputs, enabling Golgi cells to regulate the size and reproducibility of sensory responses. PMID:26432880
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Voluntary muscle activation and evoked volitional-wave responses as a function of torque.
Hight, Robert E; Quarshie, Alwyn T; Black, Christopher D
2018-08-01
This study employed a unique stimulation paradigm which allowed for the simultaneous assessment of voluntary activation levels (VA) via twitch-interpolation, and the evoked V-wave responses of the plantar flexors during submaximal and maximal contractions. Test-retest reliability was also examined. Fourteen participants repeated a stimulation protocol over four visits to assess VA and evoked V-wave amplitude across torque levels ranging from 20% to 100% MVC. MVC torque and EMG amplitude were also measured. VA increased nonlinearly with torque production and plateaued by 80% MVC. V-wave amplitude increased linearly from 20% to 100% MVC. There were no differences in any dependent variable across visits (p > 0.05). VA demonstrated moderate to substantial reliability across all torque levels (ICC = 0.76-0.91) while V-wave amplitude exhibited fair to moderate reliability from 40% to 100% (ICC = 0.48-0.74). We were able to reliably collect VA and the V-wave simultaneously in the plantar flexors. Collection of VA and V-wave during the same contraction provides distinct information regarding the contribution of motor-unit recruitment and descending cortico-spinal drive/excitability to force production. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Miskovic, Vladimir; Martinovic, Jasna; Wieser, Matthias M.; Petro, Nathan M.; Bradley, Margaret M.; Keil, Andreas
2015-01-01
Emotionally arousing scenes readily capture visual attention, prompting amplified neural activity in sensory regions of the brain. The physical stimulus features and related information channels in the human visual system that contribute to this modulation, however, are not known. Here, we manipulated low-level physical parameters of complex scenes varying in hedonic valence and emotional arousal in order to target the relative contributions of luminance based versus chromatic visual channels to emotional perception. Stimulus-evoked brain electrical activity was measured during picture viewing and used to quantify neural responses sensitive to lower-tier visual cortical involvement (steady-state visual evoked potentials) as well as the late positive potential, reflecting a more distributed cortical event. Results showed that the enhancement for emotional content was stimulus-selective when examining the steady-state segments of the evoked visual potentials. Response amplification was present only for low spatial frequency, grayscale stimuli, and not for high spatial frequency, red/green stimuli. In contrast, the late positive potential was modulated by emotion regardless of the scene’s physical properties. Our findings are discussed in relation to neurophysiologically plausible constraints operating at distinct stages of the cortical processing stream. PMID:25640949
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Miskovic, Vladimir; Martinovic, Jasna; Wieser, Matthias J; Petro, Nathan M; Bradley, Margaret M; Keil, Andreas
2015-03-01
Emotionally arousing scenes readily capture visual attention, prompting amplified neural activity in sensory regions of the brain. The physical stimulus features and related information channels in the human visual system that contribute to this modulation, however, are not known. Here, we manipulated low-level physical parameters of complex scenes varying in hedonic valence and emotional arousal in order to target the relative contributions of luminance based versus chromatic visual channels to emotional perception. Stimulus-evoked brain electrical activity was measured during picture viewing and used to quantify neural responses sensitive to lower-tier visual cortical involvement (steady-state visual evoked potentials) as well as the late positive potential, reflecting a more distributed cortical event. Results showed that the enhancement for emotional content was stimulus-selective when examining the steady-state segments of the evoked visual potentials. Response amplification was present only for low spatial frequency, grayscale stimuli, and not for high spatial frequency, red/green stimuli. In contrast, the late positive potential was modulated by emotion regardless of the scene's physical properties. Our findings are discussed in relation to neurophysiologically plausible constraints operating at distinct stages of the cortical processing stream. Copyright © 2015 Elsevier B.V. All rights reserved.
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Cooking up Psychological Operations: The Ingredients of Successful PSYOP
2011-06-01
BLANK xi LIST OF ACRONYMS AND ABBREVIATIONS 1 st L&L First Loudspeaker and Leaflet Company 1 st RB&L First Radio Broadcast and Leaflet Group ...of War Information OSS Office of Strategic Studies PO Psychological Operations Objective POG Psychological Operations Group POW Prisoner...in 1942, the Office of the Chief of Psychological Warfare (OCPW), established in 1951, and since 1967, the 4 th Psychological Operations Group (POG
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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.
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Boxell, Emily M; Smith, Samuel G; Morris, Melanie; Kummer, Sonja; Rowlands, Gill; Waller, Jo; Wardle, Jane; Simon, Alice E
2012-01-01
Health literacy may influence the efficacy of print-based public health interventions. A key part of the U.K. cancer control strategy is to provide information to the public on earlier diagnoses with a view to improving the United Kingdom's relatively poor 1-year cancer survival statistics. This study examined the effect of health literacy on the efficacy of a gynecological cancer information leaflet. Participants (n = 451) were recruited from 17 Cancer Research UK events. Health literacy was assessed with the Newest Vital Sign test. Gynecological cancer symptom awareness and barriers to medical help seeking were assessed before and after participants read the leaflet. Symptom awareness improved, and barriers to medical help seeking were reduced (ps < .001). Symptom awareness was lower in individuals in lower health literacy groups, both at baseline and at follow-up (p < .05, p < .001, respectively), but there were no significant differences in barriers to medical help seeking at either time point (p > .05). As predicted, individuals with lower health literacy benefited less after exposure to the leaflet (ps < .01 for interactions). Despite careful consideration of information design principles in the development of the leaflet, more intensive efforts may be required to ensure that inequalities are not exacerbated by reliance on print-based public health interventions.
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Padala, Muralidhar; Gyoneva, Lazarina I; Thourani, Vinod H; Yoganathan, Ajit P
2014-01-01
Mitral valve geometry is significantly altered secondary to left ventricular remodeling in non-ischemic and ischemic dilated cardiomyopathies. Since the extent of remodeling and asymmetry of dilatation of the ventricle differ significantly between individual patients, the valve geometry and tethering also differ. The study aim was to determine if mitral valve geometry has an impact on the efficacy of surgical repairs to eliminate regurgitation and restore valve closure in a validated experimental model. Porcine mitral valves (n = 8) were studied in a pulsatile heart simulator, in which the mitral valve geometry can be precisely altered and controlled throughout the experiment. Baseline hemodynamics for each valve were measured (Control), and the valves were tethered in two distinct ways: annular dilatation with 7 mm apical papillary muscle (PM) displacement (Tether 1, symmetric), and annular dilatation with 7 mm apical, 7 mm posterior and 7 mm lateral PM displacement (Tether 2, asymmetric). Mitral annuloplasty was performed on each valve (Annular Repair), succeeded by anterior leaflet secondary chordal cutting (Sub-annular Repair). The efficacy of each repair in the setting of a given valve geometry was quantified by measuring the changes in mitral regurgitation (MR), leaflet coaptation length, tethering height and area. At baseline, none of the valves was regurgitant. Significant leaflet tethering was measured in Tether 2 over Tether 1, but both groups were significantly higher compared to baseline (60.9 +/- 31 mm2 for Control versus 129.7 +/- 28.4 mm2 for Tether 1 versus 186.4 +/- 36.3 mm2 for Tether 2). Consequently, the MR fraction was higher in Tether 2 group (23.0 +/- 5.7%) than in Tether 1 (10.5 +/- 5.5%). Mitral annuloplasty reduced MR in both groups, but remnant regurgitation after the repair was higher in Tether 2. After chordal cutting a similar trend was observed with trace regurgitation in Tether 1 group at 3.6 +/- 2.8%, in comparison to 18.6 +/- 4.2% in the Tether 2 group. In this experimental model, the tethering geometry of the mitral valve impacts the valve hemodynamics after annuloplasty and chordal cutting. The quantitative assessment of valve geometry may help in tailoring a repair to the specific tethering pattern.
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Jankowski, Kathryn F; Takahashi, Hidehiko
2014-05-01
Social emotions are affective states elicited during social interactions and integral for promoting socially appropriate behaviors and discouraging socially inappropriate ones. Social emotion-processing deficits significantly impair interpersonal relationships, and play distinct roles in the manifestation and maintenance of clinical symptomatology. Elucidating the neural correlates of discrete social emotions can serve as a window to better understanding and treating neuropsychiatric disorders. Moral cognition and social emotion-processing broadly recruit a fronto-temporo-subcortical network, supporting empathy, perspective-taking, self-processing, and reward-processing. The present review specifically examines the neural correlates of embarrassment, guilt, envy, and schadenfreude. Embarrassment and guilt are self-conscious emotions, evoked during negative evaluation following norm violations and supported by a fronto-temporo-posterior network. Embarrassment is evoked by social transgressions and recruits greater anterior temporal regions, representing conceptual social knowledge. Guilt is evoked by moral transgressions and recruits greater prefrontal regions, representing perspective-taking and behavioral change demands. Envy and schadenfreude are fortune-of-other emotions, evoked during social comparison and supported by a prefronto-striatal network. Envy represents displeasure in others' fortunes, and recruits increased dorsal anterior cingulate cortex, representing cognitive dissonance, and decreased reward-related striatal regions. Schadenfreude represents pleasure in others' misfortunes, and recruits reduced empathy-related insular regions and increased reward-related striatal regions. Implications for psychopathology and treatment design are discussed. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.
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Aitken, Tara J.; Greenfield, Venuz Y.; Wassum, Kate M.
2016-01-01
Environmental reward-predictive stimuli provide a major source of motivation for instrumental reward-seeking activity and this has been linked to dopamine signaling in the nucleus accumbens (NAc). This cue-induced incentive motivation can be quite general, not restricted to instrumental actions that earn the same unique reward, and is also typically regulated by one’s current need state, such that cues only motivate actions when this is adaptive. But it is unknown whether cue-evoked dopamine signaling is similarly regulated by need state. Here we used fast-scan cyclic voltammetry to monitor dopamine concentration changes in the NAc core of rats during a Pavlovian-to-instrumental transfer (PIT) task in which the motivating influence of two cues, each signaling a distinct food reward (sucrose or food pellets), over an action earning a third unique food reward (grape-flavored polycose) was assessed in a state of hunger and of satiety. Both cues elicited a robust NAc dopamine response when hungry. The magnitude of the sucrose cue-evoked dopamine response correlated with the PIT effect that was selectively induced by this stimulus. Satiety attenuated these cue-evoked dopamine responses and behavioral responding, even though rats had never experienced the specific food rewards in this state. These data demonstrate that cue-evoked NAc core responses are sensitive to current need state, one critical variable that determines the current adaptive utility of cue-motivated behavior. PMID:26715366
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Chen, Chen-Wen; Chen, Qian-Bo; Ouyang, Qing; Sun, Ji-Hu; Liu, Fang-Ting; Song, Dian-Wen; Yuan, Hong-Bin
2012-06-25
Activated microglia exerts both beneficial and deleterious effects on neurons, but the signaling mechanism controlling these distinct responses remain unclear. We demonstrated that treatment of microglial cultures with the PAR-2 agonist, 2-Furoyl-LIGRLO-NH2, evoked early transient release of BDNF, while sustained PAR-2 stimulation evoked the delayed release of inflammatory cytokines (IL-1 β and TNF-α) and nitric oxide. Culture medium harvested during the early phase (at 1 h) of microglial activation induced by 2-Furoyl-LIGRLO-NH2 (microglial conditioned medium, MCM) had no deleterious effects on cultured neurons, while MCM harvested during the late phase (at 72 h) promoted DNA fragmentation and apoptosis as indicated by TUNEL and annexin/PI staining. Blockade of PAR-1 during the early phase of PAR-2 stimulation enhanced BDNF release (by 11%, small but significant) while a PAR-1 agonist added during the late phase (24 h after 2-Furoyl-LIGRLO-NH2 addition) suppressed the release of cytokines and NO. The neuroprotective and neurotoxic effects of activated microglial exhibit distinct temporal profiles that are regulated by PAR-1 and PAR-2 stimulation. It may be possible to facilitate neuronal recovery and repair by appropriately timed stimulation and inhibition of microglial PAR-1 and PAR-2 receptors.
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McCaughey, Stuart A.
2008-01-01
Sugars evoke a distinctive perceptual quality (“sweetness” in humans) and are generally highly preferred. The neural basis for these phenomena is reviewed for rodents, in which detailed electrophysiological measurements have been made. A receptor has been identified that binds sweeteners and activates G-protein-mediated signaling in taste receptor cells, which leads to changes in neural firing rates in the brain, where perceptions of taste quality, intensity, and palatability are generated. Most cells in gustatory nuclei are broadly-tuned, so quality perception presumably arises from patterns of activity across neural populations. However, some manipulations affect only the most sugar-oriented cells, making it useful to consider them as a distinct neural subtype. Quality perception may also arise partly due to temporal patterns of activity to sugars, especially within sugar-oriented cells that give large but delayed responses. Non-specific gustatory neurons that are excited by both sugars and unpalatable stimuli project to ventral forebrain areas, where neural responses provide a closer match with behavioral preferences. This transition likely involves opposing excitatory and inhibitory influences by different subgroups of gustatory cells. Sweeteners are generally preferred over water, but the strength of this preference can vary across time or between individuals, and higher preferences for sugars are often associated with larger taste-evoked responses. PMID:18499254
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Empathic Concern Is Part of a More General Communal Emotion.
Zickfeld, Janis H; Schubert, Thomas W; Seibt, Beate; Fiske, Alan P
2017-01-01
Seeing someone in need may evoke a particular kind of closeness that has been conceptualized as sympathy or empathic concern (which is distinct from other empathy constructs). In other contexts, when people suddenly feel close to others, or observe others suddenly feeling closer to each other, this sudden closeness tends to evoke an emotion often labeled in vernacular English as being moved, touched , or heart-warming feelings. Recent theory and empirical work indicates that this is a distinct emotion; the construct is named kama muta . Is empathic concern for people in need simply an expression of the much broader tendency to respond with kama muta to all kinds of situations that afford closeness, such as reunions, kindness, and expressions of love? Across 16 studies sampling 2918 participants, we explored whether empathic concern is associated with kama muta. Meta-analyzing the association between ratings of state being moved and trait empathic concern revealed an effect size of, r (3631) = 0.35 [95% CI: 0.29, 0.41]. In addition, trait empathic concern was also associated with self-reports of the three sensations that have been shown to be reliably indicative of kama muta: weeping, chills, and bodily feelings of warmth. We conclude that empathic concern might actually be a part of the kama muta construct.
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Empathic Concern Is Part of a More General Communal Emotion
Zickfeld, Janis H.; Schubert, Thomas W.; Seibt, Beate; Fiske, Alan P.
2017-01-01
Seeing someone in need may evoke a particular kind of closeness that has been conceptualized as sympathy or empathic concern (which is distinct from other empathy constructs). In other contexts, when people suddenly feel close to others, or observe others suddenly feeling closer to each other, this sudden closeness tends to evoke an emotion often labeled in vernacular English as being moved, touched, or heart-warming feelings. Recent theory and empirical work indicates that this is a distinct emotion; the construct is named kama muta. Is empathic concern for people in need simply an expression of the much broader tendency to respond with kama muta to all kinds of situations that afford closeness, such as reunions, kindness, and expressions of love? Across 16 studies sampling 2918 participants, we explored whether empathic concern is associated with kama muta. Meta-analyzing the association between ratings of state being moved and trait empathic concern revealed an effect size of, r(3631) = 0.35 [95% CI: 0.29, 0.41]. In addition, trait empathic concern was also associated with self-reports of the three sensations that have been shown to be reliably indicative of kama muta: weeping, chills, and bodily feelings of warmth. We conclude that empathic concern might actually be a part of the kama muta construct. PMID:28539901
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The Islamic State Battle Plan: Press Release Natural Language Processing
2016-06-01
Processing, text mining , corpus, generalized linear model, cascade, R Shiny, leaflet, data visualization 15. NUMBER OF PAGES 83 16. PRICE CODE...Terrorism and Responses to Terrorism TDM Term Document Matrix TF Term Frequency TF-IDF Term Frequency-Inverse Document Frequency tm text mining (R...package=leaflet. Feinerer I, Hornik K (2015) Text Mining Package “tm,” Version 0.6-2. (Jul 3) https://cran.r-project.org/web/packages/tm/tm.pdf
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Fox, P R; Miller, M W; Liu, S K
1992-11-15
Mitral stenosis was diagnosed noninvasively by echocardiography and Doppler imaging in 2 Bull Terriers. Two-dimensional echocardiography revealed severe atrial and moderate left ventricular dilatation; severely reduced mitral valve opening excursion; doming of the cranial mitral valve leaflet into the left ventricle during diastole; thickened, nodular cranial mitral valve leaflets; and reduced mitral valve orifice. M-mode echocardiographic findings additionally indicated greatly diminished mitral valve E to F slope and abnormal caudal mitral valve leaflet motion. Color flow Doppler imaging revealed bright bursts of color with aliasing originating from the stenotic mitral valve orifice, extending into the left atrium during systole, and into the left atrium during diastole. Spectral Doppler recordings revealed transvalvular mitral valve gradients and prolonged pressure half-times. Necropsy performed on 1 dog revealed extremely thickened, nodular, and stiff mitral valves with short, thickened, and fused chordae tendineae. The diagnosis of mitral valve stenosis was easily facilitated with diagnostic ultrasonography.
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[Valvuloplasty with balloon catheter in biologic prosthesis. Reality or illusion].
Ledesma Velasco, M; Verdín Vázquez, R; Acosta Valdez, J L; Munayer Calderón, J; Salgado Escobar, J L; Arias Monroy, L; Flores Mendoza, J
1989-01-01
We performed catheter balloon valvuloplasty (CBV) on 8 stenotic operatively-excised bioprosthetic valves (2 Hancock and 6 Ionescu Shiley). Pathology of valves before CBV included degenerative changes: commissural fusion by mounds of calcific deposits (2 valves), fibrotic and focally calcified leaflets (7 valves) and stiff and thick valves (1 valve). Inflation of the balloon resulted in commissural splitting (2 valves), leaflet cracks and fractures (3 valves). Removal of the deflated balloon catheter was associated with debris dislodgement (3 valves). In one case the valve was unable to close with potential for acute regurgitation. Thus, CBV of bioprosthetic valves can split fused commissures by similar mechanisms as in native valves. CBV may fracture calcific deposits causing acute emboli. It can also disrupt the leaflets causing acute insufficiency. The findings suggest a limited role of CBV in the treatment of stenotic bioprosthetic valves in mitral and aortic position.
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Selective propensity of bovine jugular vein material to bacterial adhesions: An in-vitro study.
Jalal, Zakaria; Galmiche, Louise; Lebeaux, David; Villemain, Olivier; Brugada, Georgia; Patel, Mehul; Ghigo, Jean-Marc; Beloin, Christophe; Boudjemline, Younes
2015-11-01
Percutaneous pulmonary valve implantation (PPVI) using Melody valve made of bovine jugular vein is safe and effective. However, infective endocarditis has been reported for unclear reasons. We sought to assess the impact of valvular substrates on selective bacterial adhesion. Three valved stents (Melody valve, homemade stents with bovine and porcine pericardium) were tested in-vitro for bacterial adhesion using Staphylococcus aureus and Streptococcus sanguinis strains. Bacterial adhesion was higher on bovine jugular venous wall for S. aureus and on Melody valvular leaflets for S. sanguinis in control groups and significantly increased in traumatized Melody valvular leaflets with both bacteria (traumatized vs non traumatized: p=0.05). Bacterial adhesion was lower on bovine pericardial leaflets. Selective adhesion of S. aureus and S. sanguinis pathogenic strains to Melody valve tissue was noted on healthy tissue and increased after implantation procedural steps. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
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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.
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Detection of cholesterol-rich microdomains in the inner leaflet of the plasma membrane
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hayashi, Masami; Shimada, Yukiko; Inomata, Mitsushi
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 tomore » intracellular membranes. Taken together, these results strongly suggest the existence of cholesterol-rich microdomains in the inner leaflet of the plasma membrane.« less
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Kelley, Thomas M; Kashem, Mohammed; Wang, He; McCarthy, James; Carroll, Nels D; Moser, G William; Guy, T Sloane
2017-01-01
This study reported on the treatment of Carpentier type IIIa and type IIIb mitral regurgitation (MR) with a large patch anterior mitral valve leaflet augmentation technique using CorMatrix (CorMatrix Cardiovascular Inc, Alpharetta, GA) extracellular matrix (ECM). A single-site chart review was conducted on patients who underwent anterior leaflet augmentation performed with the Da Vinci surgical robot (Intuitive Surgical, Sunnyvale, CA) or through a median sternotomy. Only patients who had anterior leaflet augmentation with porcine intestine ECM or autologous pericardium were included. Follow-up echocardiography was performed on all patients. Histologic specimens were available on ECM patches from a subset of patients who required reoperation. Between August 2011 and April 2014, 44 patients (mean age, 62.6 ± 12.2 years) underwent anterior leaflet augmentation with either porcine intestinal ECM or autologous pericardium at the Temple University Hospital in Philadelphia. Two (4%) late deaths occurred, one in each group. One patient who underwent ECM augmentation died of non-cardiac-related causes 7 months after discharge as a result of complications of chronic renal failure. The second late death occurred 5 months after discharge because of complications of a stroke in a patient in the pericardial augmentation group. Eight (32%) of the patients with ECM had recurrence of severe MR on echocardiography at an average time of 201 ± 98 days. Seven (28%) patients required reoperation because of failure of the ECM patch including perforation (4%), excessive patch dilation (20%), and suture line dehiscence (4%). In contrast, none of the patients with pericardial augmentation developed severe MR or required operation. Statistical analysis of the patients with ECM augmentation demonstrated no correlation of the following: age; sex; comorbid conditions such as diabetes, chronic obstructive pulmonary disease, and hypertension; left ventricular ejection fraction; surgical approach; annuloplasty size; or type of MR with patch failure. A lower body mass index was the only factor associated with recurrent severe regurgitation on univariate analysis (p = 0.039). Histologic study of the four available explants demonstrated intense inflammation without evidence of host integration. The remaining 15 (60%) patients had normal mitral leaflet structure and function on follow-up echocardiograms out to 12 months. For type III MR, a large anterior leaflet patch technique with porcine ECM was associated with a 32% recurrence rate of severe MR related directly to patch failure. Further research and development should be performed on the use of ECM materials with a goal to decrease the failure rate experienced in this study. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
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Deconstruction of a neural circuit for hunger.
Atasoy, Deniz; Betley, J Nicholas; Su, Helen H; Sternson, Scott M
2012-08-09
Hunger is a complex behavioural state that elicits intense food seeking and consumption. These behaviours are rapidly recapitulated by activation of starvation-sensitive AGRP neurons, which present an entry point for reverse-engineering neural circuits for hunger. Here we mapped synaptic interactions of AGRP neurons with multiple cell populations in mice and probed the contribution of these distinct circuits to feeding behaviour using optogenetic and pharmacogenetic techniques. An inhibitory circuit with paraventricular hypothalamus (PVH) neurons substantially accounted for acute AGRP neuron-evoked eating, whereas two other prominent circuits were insufficient. Within the PVH, we found that AGRP neurons target and inhibit oxytocin neurons, a small population that is selectively lost in Prader-Willi syndrome, a condition involving insatiable hunger. By developing strategies for evaluating molecularly defined circuits, we show that AGRP neuron suppression of oxytocin neurons is critical for evoked feeding. These experiments reveal a new neural circuit that regulates hunger state and pathways associated with overeating disorders.
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Deconstruction of a neural circuit for hunger
Atasoy, Deniz; Betley, J. Nicholas; Su, Helen H.; Sternson, Scott M.
2012-01-01
Hunger is a complex behavioural state that elicits intense food seeking and consumption. These behaviours are rapidly recapitulated by activation of starvation-sensitive AGRP neurons, which present an entry point for reverse-engineering neural circuits for hunger. We mapped synaptic interactions of AGRP neurons with multiple cell populations and probed the contribution of these distinct circuits to feeding behaviour using optogenetic and pharmacogenetic techniques. An inhibitory circuit with paraventricular hypothalamus (PVH) neurons substantially accounted for acute AGRP neuron-evoked eating, whereas two other prominent circuits were insufficient. Within the PVH, we found that AGRP neurons target and inhibit oxytocin neurons, a small population that is selectively lost in Prader-Willi syndrome, a condition involving insatiable hunger. By developing strategies for evaluating molecularly-defined circuits, we show that AGRP neuron suppression of oxytocin neurons is critical for evoked feeding. These experiments reveal a new neural circuit that regulates hunger state and pathways associated with overeating disorders. PMID:22801496
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Ishii, K; Koga, Y; Maeda, M; Nakamura, K; Sekiya, R; Yonezawa, T; Onitsuka, T; Shibata, K
1988-01-01
A 70-year-old male with tricuspid regurgitation due to a blunt chest trauma inflicted 16 years previously underwent prosthetic valve replacement. At surgery, a tear, which produced tricuspid regurgitation, was found around the annulus of the anterior leaflet of the tricuspid valve. Since this area has not been reported as a location for heart trauma-producing tricuspid regurgitation, a possible mechanism of tricuspid regurgitation is discussed in this patient.
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Rauch, Cyril; Loughna, Paul T
2005-01-01
The plasma membrane is composed of two leaflets that are asymmetric with regard to their phospholipid composition with phosphatidylserine (PS) predominantly located within the inner leaflet whereas other phospholipids such as phosphatidylcholine (PC) are preferentially located in the outer leaflet. An intimate relationship between cellular physiology and the composition of the plasma membrane has been demonstrated, with for example apoptosis requiring PS exposure for macrophage recognition. In skeletal muscle development, differentiation also requires PS exposure in myoblasts to create cell-cell contact areas allowing the formation of multinucleate myotubes. Although it is clearly established that membrane composition/asymmetry plays an important role in cellular physiology, the role of cytokines in regulating this asymmetry is still unclear. When incubated with myoblasts, insulin-like growth factor I (IGF-1) has been shown to promote proliferation versus differentiation in a concentration dependent manner and therefore, may be a potential candidate regulating cell membrane asymmetry. We show, in non-apoptotic C2C12 cells, that relocation of an exogenous PS analogue, from the outer into the inner leaflet, is accelerated by IGF-1 in a concentration-dependent manner and that maintenance of membrane asymmetry triggered by IGF-1 is however independent of the PI3K inhibitor wortmannin. Copyright (c) 2005 John Wiley & Sons, Ltd.
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McGregor, Lesley M.; von Wagner, Christian; Atkin, Wendy; Kralj-Hans, Ines; Halloran, Stephen P.; Handley, Graham; Logan, Richard F.; Rainbow, Sandra; Smith, Steve; Snowball, Julia; Thomas, Mary C.; Smith, Samuel G.; Vart, Gemma; Howe, Rosemary; Counsell, Nicholas; Hackshaw, Allan; Morris, Stephen; Duffy, Stephen W.; Raine, Rosalind; Wardle, Jane
2016-01-01
Objective. To test the effectiveness of adding a narrative leaflet to the current information material delivered by the NHS English colorectal cancer (CRC) screening programme on reducing socioeconomic inequalities in uptake. Participants. 150,417 adults (59–74 years) routinely invited to complete the guaiac Faecal Occult Blood test (gFOBt) in March 2013. Design. A cluster randomised controlled trial (ISRCTN74121020) to compare uptake between two arms. The control arm received the standard NHS CRC screening information material (SI) and the intervention arm received the standard information plus a supplementary narrative leaflet, which had previously been shown to increase screening intentions (SI + N). Between group comparisons were made for uptake overall and across socioeconomic status (SES). Results. Uptake was 57.7% and did not differ significantly between the two trial arms (SI: 58.5%; SI + N: 56.7%; odds ratio = 0.93; 95% confidence interval: 0.81–1.06; p = 0.27). There was no interaction between group and SES quintile (p = 0.44). Conclusions. Adding a narrative leaflet to existing information materials does not reduce the SES gradient in uptake. Despite the benefits of using a pragmatic trial design, the need to add to, rather than replace, existing information may have limited the true value of an evidence-based intervention on behaviour. PMID:27069473
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A review of state-of-the-art numerical methods for simulating flow through mechanical heart valves.
Sotiropoulos, Fotis; Borazjani, Iman
2009-03-01
In nearly half of the heart valve replacement surgeries performed annually, surgeons prefer to implant bileaflet mechanical heart valves (BMHV) because of their durability and long life span. All current BMHV designs, however, are prone to thromboembolic complications and implant recipients need to be on a life-long anticoagulant medication regiment. Non-physiologic flow patterns and turbulence generated by the valve leaflets are believed to be the major culprit for the increased risk of thromboembolism in BMHV implant recipients. In this paper, we review recent advances in developing predictive fluid-structure interaction (FSI) algorithms that can simulate BMHV flows at physiologic conditions and at resolution sufficiently fine to start probing the links between hemodynamics and blood-cell damage. Numerical simulations have provided the first glimpse into the complex hemodynamic environment experienced by blood cells downstream of the valve leaflets and successfully resolved for the first time the experimentally observed explosive transition to a turbulent-like state at the start of the decelerating flow phase. The simulations have also resolved a number of subtle features of experimentally observed valve kinematics, such as the asymmetric opening and closing of the leaflets and the leaflet rebound during closing. The paper also discusses a future research agenda toward developing a powerful patient-specific computational framework for optimizing valve design and implantation in a virtual surgery environment.
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P-glycoprotein substrate transport assessed by comparing cellular and vesicular ATPase activity.
Nervi, Pierluigi; Li-Blatter, Xiaochun; Aänismaa, Päivi; Seelig, Anna
2010-03-01
We compared the P-glycoprotein ATPase activity in inside-out plasma membrane vesicles and living NIH-MDR1-G185 cells with the aim to detect substrate transport. To this purpose we used six substrates which differ significantly in their passive influx through the plasma membrane. In cells, the cytosolic membrane leaflet harboring the substrate binding site of P-glycoprotein has to be approached by passive diffusion through the lipid membrane, whereas in inside-out plasma membrane vesicles, it is accessible directly from the aqueous phase. Compounds exhibiting fast passive influx compared to active efflux by P-glycoprotein induced similar ATPase activity profiles in cells and inside-out plasma membrane vesicles, because their concentrations in the cytosolic leaflets were similar. Compounds exhibiting similar influx as efflux induced in contrast different ATPase activity profiles in cells and inside-out vesicles. Their concentration was significantly lower in the cytosolic leaflet of cells than in the cytosolic leaflet of inside-out membrane vesicles, indicating that P-glycoprotein could cope with passive influx. P-glycoprotein thus transported all compounds at a rate proportional to ATP hydrolysis (i.e. all compounds were substrates). However, it prevented substrate entry into the cytosol only if passive influx of substrates across the lipid bilayer was in a similar range as active efflux. Copyright 2009 Elsevier B.V. All rights reserved.
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A review of state-of-the-art numerical methods for simulating flow through mechanical heart valves
Borazjani, Iman
2009-01-01
In nearly half of the heart valve replacement surgeries performed annually, surgeons prefer to implant bileaflet mechanical heart valves (BMHV) because of their durability and long life span. All current BMHV designs, however, are prone to thromboembolic complications and implant recipients need to be on a life-long anticoagulant medication regiment. Non-physiologic flow patterns and turbulence generated by the valve leaflets are believed to be the major culprit for the increased risk of thromboembolism in BMHV implant recipients. In this paper, we review recent advances in developing predictive fluid–structure interaction (FSI) algorithms that can simulate BMHV flows at physiologic conditions and at resolution sufficiently fine to start probing the links between hemodynamics and blood-cell damage. Numerical simulations have provided the first glimpse into the complex hemodynamic environment experienced by blood cells downstream of the valve leaflets and successfully resolved for the first time the experimentally observed explosive transition to a turbulent-like state at the start of the decelerating flow phase. The simulations have also resolved a number of subtle features of experimentally observed valve kinematics, such as the asymmetric opening and closing of the leaflets and the leaflet rebound during closing. The paper also discusses a future research agenda toward developing a powerful patient-specific computational framework for optimizing valve design and implantation in a virtual surgery environment. PMID:19194734
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Tong, Vivien; Raynor, David K; Aslani, Parisa
2018-04-01
To explore Australian and UK consumers' receipt and use of spoken and written medicine information and examine the role of leaflets for consumers of over-the-counter (OTC) medicines. Semistructured interviews were conducted with 37 Australian and 39 UK consumers to explore information received with their most recent OTC medicine purchase, and how information was used at different times post-purchase. Interviews were audio-recorded, transcribed verbatim and thematically analysed. Similarities were evident between the key themes identified from Australian and UK consumers' experiences. Consumers infrequently sought spoken information and reported that pharmacy staff provided minimal spoken information for OTC medicines. Leaflets were not always received or wanted and had a less salient role as an information source for repeat OTC purchases. Consumers tended not to read OTC labels or leaflets. Product familiarity led to consumers tending not to seek information on labels or leaflets. When labels were consulted, directions for use were commonly read. However, OTC medicine information in general was infrequently revisited. As familiarity is not an infallible proxy for safe and effective medication use, strategies to promote the value and use of these OTC medicine information sources are important and needed. Minimal spoken information provision coupled with limited written information use may adversely impact medication safety in self-management. © 2017 Royal Pharmaceutical Society.
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Getting to the Outer Leaflet: Physiology of Phosphatidylserine Exposure at the Plasma Membrane.
Bevers, Edouard M; Williamson, Patrick L
2016-04-01
Phosphatidylserine (PS) is a major component of membrane bilayers whose change in distribution between inner and outer leaflets is an important physiological signal. Normally, members of the type IV P-type ATPases spend metabolic energy to create an asymmetric distribution of phospholipids between the two leaflets, with PS confined to the cytoplasmic membrane leaflet. On occasion, membrane enzymes, known as scramblases, are activated to facilitate transbilayer migration of lipids, including PS. Recently, two proteins required for such randomization have been identified: TMEM16F, a scramblase regulated by elevated intracellular Ca(2+), and XKR8, a caspase-sensitive protein required for PS exposure in apoptotic cells. Once exposed at the cell surface, PS regulates biochemical reactions involved in blood coagulation, and bone mineralization, and also regulates a variety of cell-cell interactions. Exposed on the surface of apoptotic cells, PS controls their recognition and engulfment by other cells. This process is exploited by parasites to invade their host, and in specialized form is used to maintain photoreceptors in the eye and modify synaptic connections in the brain. This review discusses what is known about the mechanism of PS exposure at the surface of the plasma membrane of cells, how actors in the extracellular milieu sense surface exposed PS, and how this recognition is translated to downstream consequences of PS exposure. Copyright © 2016 the American Physiological Society.
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Ropcke, Diana M; Rasmussen, Jonas; Ilkjær, Christine; Skov, Søren N; Tjørnild, Marcell J; Baandrup, Ulrik T; Christian Danielsen, Carl; Hjortdal, Vibeke E; Nielsen, Sten L
2018-04-11
Tricuspid valve reconstruction using a small intestinal submucosal porcine extracellular matrix (ECM) tube graft is hypothesized to be durable for six months and show signs of recellularization and growth potential. The purpose was to histologically and biomechanically test ECM valves before and after six months of implantation in pigs for comparison with native valves. Ten 60 kg pigs were included, which survived tricuspid valve tube graft insertion. Anterior and septal tricuspid leaflets were explanted from all animals surviving more than one month and examined histologically (n = 9). Endothelialization, collagen content, mineralization, neovascularization, burst strength and tensile strength were determined for native valves (n = 5), ECM before implantation (n = 5), and ECM after six months (n = 5). Collagen density was significantly larger in ECM at implantation (baseline) compared to native leaflet tissue (0.3 ± 0.02 mg/mm 3 vs. 0.1 ± 0.03 mg/mm 3 , p < .0001), but collagen density decreased and reached native leaflet collagen content, six months after ECM implantation (native vs. ECM valve at six months: 0.1 ± 0.03 mg/mm 3 vs. 0.2 ± 0.05 mg/mm 3 , p = .8). Histologically, ECM valves showed endothelialization, host cell infiltration and structural collagen organization together with elastin generation after six months, indicating tissue remodeling and -engineering together with gradual development of a close-to-native leaflet structure without foreign body response. ECM tricuspid tube grafts were stronger than native leaflet tissue. Histologically, the acellular ECM tube grafts showed evidence of constructive tissue remodeling with endothelialization and connective tissue organization. These findings support the concept of tissue engineering and recellularization, which are prerequisites for growth. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Sai-Sudhakar, Chittoor B; Vandse, Rashmi; Armen, Todd A; Bickle, Katherine M; Nathan, Nadia S
2007-01-01
Background Ischemic mitral regurgitation often complicates severe ischemic heart disease and adversely affects the prognosis in these patients. There is wide variation in the clinical spectrum of ischemic mitral regurgitation due to varying location and chronicity of ischemia and anomalies in annular and ventricular remodeling. As a result, there is lack of consensus in treating these patients. Treatment has to be individualized for each patient. Most of the available surgical options do not consistently correct this condition in all the patients. Chordal cutting is one of the newer surgical approaches in which cutting a limited number of critically positioned basal chordae have found success by relieving the leaflet tethering and thereby improving the coaptation of leaflets. Three-dimensional echocardiography is a potentially valuable tool in identifying the specific pattern of tethering and thus the suitability of this procedure in a given clinical scenario. Case Presentation A 66-year-old man with cardiomyopathy and ischemic mitral regurgitation presented to us with the features of congestive heart failure. The three-dimensional echocardiography revealed severe mitral regurgitation associated with the tethering of the lateral (P1) and medial (P3) scallops of the posterior leaflet of the mitral valve due to secondary chordal attachments. The ejection fraction was only 15% with severe global systolic and diastolic dysfunction. Mitral regurgitation was successfully corrected with mitral annuloplasty and resection of the secondary chordae tethering the medial and lateral scallops of the posterior leaflet of the mitral valve. Conclusion Cutting the second order chordae along with mitral annuloplasty could be a novel method to remedy Ischemic mitral regurgitation by relieving the tethering of the valve leaflets. The preoperative three-dimensional echocardiography should be considered in all patients with Ischemic mitral regurgitation to assess the complex three-dimensional interactions between the mitral valve apparatus and the left ventricle. This aids in timely surgical planning. PMID:17894872
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Sai-Sudhakar, Chittoor B; Vandse, Rashmi; Armen, Todd A; Bickle, Katherine M; Nathan, Nadia S
2007-09-25
Ischemic mitral regurgitation often complicates severe ischemic heart disease and adversely affects the prognosis in these patients. There is wide variation in the clinical spectrum of ischemic mitral regurgitation due to varying location and chronicity of ischemia and anomalies in annular and ventricular remodeling. As a result, there is lack of consensus in treating these patients. Treatment has to be individualized for each patient. Most of the available surgical options do not consistently correct this condition in all the patients. Chordal cutting is one of the newer surgical approaches in which cutting a limited number of critically positioned basal chordae have found success by relieving the leaflet tethering and thereby improving the coaptation of leaflets. Three-dimensional echocardiography is a potentially valuable tool in identifying the specific pattern of tethering and thus the suitability of this procedure in a given clinical scenario. A 66-year-old man with cardiomyopathy and ischemic mitral regurgitation presented to us with the features of congestive heart failure. The three-dimensional echocardiography revealed severe mitral regurgitation associated with the tethering of the lateral (P1) and medial (P3) scallops of the posterior leaflet of the mitral valve due to secondary chordal attachments. The ejection fraction was only 15% with severe global systolic and diastolic dysfunction. Mitral regurgitation was successfully corrected with mitral annuloplasty and resection of the secondary chordae tethering the medial and lateral scallops of the posterior leaflet of the mitral valve. Cutting the second order chordae along with mitral annuloplasty could be a novel method to remedy Ischemic mitral regurgitation by relieving the tethering of the valve leaflets. The preoperative three-dimensional echocardiography should be considered in all patients with Ischemic mitral regurgitation to assess the complex three-dimensional interactions between the mitral valve apparatus and the left ventricle. This aids in timely surgical planning.
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Addetia, Karima; Mor-Avi, Victor; Weinert, Lynn; Salgo, Ivan S; Lang, Roberto M
2014-01-01
Differentiating between mitral valve (MV) prolapse (MVP) and MV billowing (MVB) on two-dimensional echocardiography is challenging. The aim of this study was to test the hypothesis that color-coded models of maximal leaflet displacement from the annular plane into the atrium derived from three-dimensional transesophageal echocardiography would allow discrimination between these lesions. Three-dimensional transesophageal echocardiographic imaging of the MV was performed in 50 patients with (n = 38) and without (n = 12) degenerative MV disease. Definitive diagnosis of MVP versus MVB was made using inspection of dynamic three-dimensional renderings and multiple two-dimensional cut planes extracted from three-dimensional data sets. This was used as a reference standard to test an alternative approach, wherein the color-coded parametric models were inspected for integrity of the coaptation line and location of the maximally displaced portion of the leaflet. Diagnostic interpretations of these models by two independent readers were compared with the reference standard. In all cases of MVP, the color-coded models depicted loss of integrity of the coaptation line and maximal leaflet displacement extending to the coaptation line. MVB was depicted by preserved leaflet apposition with maximal displacement away from the coaptation line. Interpretation of the 50 color-coded models by novice readers took 5 to 10 min and resulted in good agreement with the reference technique (κ = 0.81 and κ = 0.73 for the two readers). Three-dimensional color-coded models provide a static display of MV leaflet displacement, allowing differentiation between MVP and MVB, without the need to inspect multiple planes and while taking into account the saddle shape of the mitral annulus. Copyright © 2014 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.
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Clausen, Jette Aaroe; Rydahl, Eva
2016-01-01
Objectives The need for thorough patient information is increasing as maternity care becomes more medicalised. The aim was to assess the quality of written patient information on labour induction. In most Danish hospitals, misoprostol is the first-choice drug for induction in low-risk pregnancies. Misoprostol has been associated with adverse side effects and severe outcomes for mother and child and is not registered for obstetric use in Denmark. Setting Secondary care hospitals in Denmark. Data Patient information leaflets from all hospitals that used misoprostol as an induction agent by June 2015 (N=13). Design Patient leaflets were evaluated according to a validated scoring tool (International Patient Decision Aid Standards instrument, IPDAS), core elements in the Danish Health Act, and items regarding off-label use and non-registered medication. Two of the authors scored all leaflets independently. Outcome measures Women's involvement in decision-making, information on benefits and harms associated with the treatment, other justifiable treatment options, and non-registered treatment. Results Generally, the hospitals scored low on the IPDAS checklist. No hospitals encouraged women to consider their preferences. Information on side effects and adverse outcomes was poorly covered and varied substantially between hospitals. Few hospitals informed about precautions regarding outpatient inductions, and none informed about the lack of evidence on the safety of this procedure. None informed that misoprostol is not registered for induction or explained the meaning of off-label use or use of non-registered medication. Elements such as interprofessional consensus, long-term experience, and health authorities' approval were used to add credibility to the use of misoprostol. Conclusions Central criteria for patient involvement and informed consent were not met, and the patient leaflets did not inform according to current evidence on misoprostol-induced labour. Our findings indicate that patients receive very different, sometimes contradictory, information with potential ethical implications. Concerns should be given to outpatient inductions, where precise written information is of particular importance. PMID:27235300
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Mitral Valve Chordae Tendineae: Topological and Geometrical Characterization.
Khalighi, Amir H; Drach, Andrew; Bloodworth, Charles H; Pierce, Eric L; Yoganathan, Ajit P; Gorman, Robert C; Gorman, Joseph H; Sacks, Michael S
2017-02-01
Mitral valve (MV) closure depends upon the proper function of each component of the valve apparatus, which includes the annulus, leaflets, and chordae tendineae (CT). Geometry plays a major role in MV mechanics and thus highly impacts the accuracy of computational models simulating MV function and repair. While the physiological geometry of the leaflets and annulus have been previously investigated, little effort has been made to quantitatively and objectively describe CT geometry. The CT constitute a fibrous tendon-like structure projecting from the papillary muscles (PMs) to the leaflets, thereby evenly distributing the loads placed on the MV during closure. Because CT play a major role in determining the shape and stress state of the MV as a whole, their geometry must be well characterized. In the present work, a novel and comprehensive investigation of MV CT geometry was performed to more fully quantify CT anatomy. In vitro micro-tomography 3D images of ovine MVs were acquired, segmented, then analyzed using a curve-skeleton transform. The resulting data was used to construct B-spline geometric representations of the CT structures, enriched with a continuous field of cross-sectional area (CSA) data. Next, Reeb graph models were developed to analyze overall topological patterns, along with dimensional attributes such as segment lengths, 3D orientations, and CSA. Reeb graph results revealed that the topology of ovine MV CT followed a full binary tree structure. Moreover, individual chords are mostly planar geometries that together form a 3D load-bearing support for the MV leaflets. We further demonstrated that, unlike flow-based branching patterns, while individual CT branches became thinner as they propagated further away from the PM heads towards the leaflets, the total CSA almost doubled. Overall, our findings indicate a certain level of regularity in structure, and suggest that population-based MV CT geometric models can be generated to improve current MV repair procedures.
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Indersmitten, Tim; Gur, Ruben C
2003-05-01
Since the discovery of facial asymmetries in emotional expressions of humans and other primates, hypotheses have related the greater left-hemiface intensity to right-hemispheric dominance in emotion processing. However, the difficulty of creating true frontal views of facial expressions in two-dimensional photographs has confounded efforts to better understand the phenomenon. We have recently described a method for obtaining three-dimensional photographs of posed and evoked emotional expressions and used these stimuli to investigate both intensity of expression and accuracy of recognizing emotion in chimeric faces constructed from only left- or right-side composites. The participant population included 38 (19 male, 19 female) African-American, Caucasian, and Asian adults. They were presented with chimeric composites generated from faces of eight actors and eight actresses showing four emotions: happiness, sadness, anger, and fear, each in posed and evoked conditions. We replicated the finding that emotions are expressed more intensely in the left hemiface for all emotions and conditions, with the exception of evoked anger, which was expressed more intensely in the right hemiface. In contrast, the results indicated that emotional expressions are recognized more efficiently in the right hemiface, indicating that the right hemiface expresses emotions more accurately. The double dissociation between the laterality of expression intensity and that of recognition efficiency supports the notion that the two kinds of processes may have distinct neural substrates. Evoked anger is uniquely expressed more intensely and accurately on the side of the face that projects to the viewer's right hemisphere, dominant in emotion recognition.
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Developmental Changes in Sensory-Evoked Optical Intrinsic Signals in the Rat Barrel Cortex.
Sintsov, Mikhail; Suchkov, Dmitrii; Khazipov, Rustem; Minlebaev, Marat
2017-01-01
Optical Intrinsic Signal imaging (OISi) is a powerful technique for optical brain studies. OIS mainly reflects the hemodynamic response (HR) and metabolism, but it may also involve changes in tissue light scattering (LS) caused by transient cellular swelling in the active tissue. Here, we explored the developmental features of sensory-evoked OIS in the rat barrel cortex during the first 3 months after birth. Multispectral OISi revealed that two temporally distinct components contribute to the neonatal OIS: an early phase of LS followed by a late phase of HR. The contribution of LS to the early response was also evidenced by an increase in light transmission through the active barrel. The early OIS phase correlated in time and amplitude with the sensory-evoked electrophysiological response. Application of the Modified Beer-Lambert Law (MBLL) to the OIS data revealed that HR during the early phase involved only a slight decrease in blood oxygenation without any change in blood volume. In contrast, HR during the late phase manifested an adult-like increase in blood volume and oxygenation. During development, the peak time of the delayed HR progressively shortened with age, nearly reaching the stimulus onset and overlapping with the early LS phase by the fourth postnatal week. Thus, LS contributes to the sensory-evoked OIS in the barrel cortex of rats at all ages, and it dominates the early OIS phase in neonatal rats due to delayed HR. Our results are also consistent with the delayed blood oxygen level dependent (BOLD) signal in human preterm infants.
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Developmental Changes in Sensory-Evoked Optical Intrinsic Signals in the Rat Barrel Cortex
Sintsov, Mikhail; Suchkov, Dmitrii; Khazipov, Rustem; Minlebaev, Marat
2017-01-01
Optical Intrinsic Signal imaging (OISi) is a powerful technique for optical brain studies. OIS mainly reflects the hemodynamic response (HR) and metabolism, but it may also involve changes in tissue light scattering (LS) caused by transient cellular swelling in the active tissue. Here, we explored the developmental features of sensory-evoked OIS in the rat barrel cortex during the first 3 months after birth. Multispectral OISi revealed that two temporally distinct components contribute to the neonatal OIS: an early phase of LS followed by a late phase of HR. The contribution of LS to the early response was also evidenced by an increase in light transmission through the active barrel. The early OIS phase correlated in time and amplitude with the sensory-evoked electrophysiological response. Application of the Modified Beer-Lambert Law (MBLL) to the OIS data revealed that HR during the early phase involved only a slight decrease in blood oxygenation without any change in blood volume. In contrast, HR during the late phase manifested an adult-like increase in blood volume and oxygenation. During development, the peak time of the delayed HR progressively shortened with age, nearly reaching the stimulus onset and overlapping with the early LS phase by the fourth postnatal week. Thus, LS contributes to the sensory-evoked OIS in the barrel cortex of rats at all ages, and it dominates the early OIS phase in neonatal rats due to delayed HR. Our results are also consistent with the delayed blood oxygen level dependent (BOLD) signal in human preterm infants. PMID:29311827
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Basic Mechanisms of Mitral Regurgitation
Dal-Bianco, Jacob P.; Beaudoin, Jonathan
2014-01-01
Any structural or functional impairment of the mitral valve (MV) apparatus that exhausts MV tissue redundancy available for leaflet coaptation will result in mitral regurgitation (MR). The mechanism responsible for MV malcoaptation and MR can be dysfunction or structural change of the left ventricle, the papillary muscles, the chordae tendineae, the mitral annulus and the MV leaflets. The rationale for MV treatment depends on the MR mechanism and therefore it is essential to identify and understand normal and abnormal MV and MV apparatus function. PMID:25151282
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Buffer kinetics shape the spatiotemporal patterns of IP3-evoked Ca2+ signals
Dargan, Sheila L; Parker, Ian
2003-01-01
Ca2+ liberation through inositol 1,4,5-trisphosphate receptors (IP3Rs) plays a universal role in cell regulation, and specificity of cell signalling is achieved through the spatiotemporal patterning of Ca2+ signals. IP3Rs display Ca2+-induced Ca2+ release (CICR), but are grouped in clusters so that regenerative Ca2+ signals may remain localized to individual clusters, or propagate globally between clusters by successive cycles of Ca2+ diffusion and CICR. We used confocal microscopy and photoreleased IP3 in Xenopus oocytes to study how these properties are modulated by mobile cytosolic Ca2+ buffers. EGTA (a buffer with slow ‘on-rate’) speeded Ca2+ signals and ‘balkanized’ Ca2+ waves by dissociating them into local signals. In contrast, BAPTA (a fast buffer with similar affinity) slowed Ca2+ responses and promoted ‘globalization’ of spatially uniform Ca2+ signals. These actions are likely to arise through differential effects on Ca2+ feedback within and between IP3R clusters, because Ca2+ signals evoked by influx through voltage-gated channels were little affected. We propose that cell-specific expression of Ca2+-binding proteins with distinct kinetics may shape the time course and spatial distribution of IP3-evoked Ca2+ signals for specific physiological roles. PMID:14555715
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Processing of odor mixtures in the zebrafish olfactory bulb.
Tabor, Rico; Yaksi, Emre; Weislogel, Jan-Marek; Friedrich, Rainer W
2004-07-21
Components of odor mixtures often are not perceived individually, suggesting that neural representations of mixtures are not simple combinations of the representations of the components. We studied odor responses to binary mixtures of amino acids and food extracts at different processing stages in the olfactory bulb (OB) of zebrafish. Odor-evoked input to the OB was measured by imaging Ca2+ signals in afferents to olfactory glomeruli. Activity patterns evoked by mixtures were predictable within narrow limits from the component patterns, indicating that mixture interactions in the peripheral olfactory system are weak. OB output neurons, the mitral cells (MCs), were recorded extra- and intracellularly and responded to odors with stimulus-dependent temporal firing rate modulations. Responses to mixtures of amino acids often were dominated by one of the component responses. Responses to mixtures of food extracts, in contrast, were more distinct from both component responses. These results show that mixture interactions can result from processing in the OB. Moreover, our data indicate that mixture interactions in the OB become more pronounced with increasing overlap of input activity patterns evoked by the components. Emerging from these results are rules of mixture interactions that may explain behavioral data and provide a basis for understanding the processing of natural odor stimuli in the OB.
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Oron, Y; Gillo, B; Gershengorn, M C
1988-06-01
Xenopus laevis oocytes are giant cells suitable for studies of plasma membrane receptors and signal transduction pathways because of their capacity to express receptors after injection of heterologous mRNA. We studied depolarizing chloride currents evoked by acetylcholine (AcCho) in native oocytes ("intrinsic AcCho response"), by thyrotropin-releasing hormone (TRH) in oocytes injected with pituitary (GH3) cell RNA ("acquired TRH response"), and by AcCho in oocytes injected with rat brain RNA ("acquired AcCho response"). We found differences in the latencies and patterns of these responses and in the responsiveness to these agonists when applied to the animal or vegetal hemisphere, even though all of the responses are mediated by the same signal transduction pathway. The common intrinsic response to AcCho is characterized by minimal latency (0.86 +/- 0.05 sec), a rapid, transient depolarization followed by a distinct prolonged depolarization, and larger responses obtained after AcCho application at the vegetal rather than the animal hemisphere. By contrast, the acquired responses to TRH and AcCho are characterized by much longer latencies, 9.3 +/- 1.0 and 5.5 +/- 0.8 sec, respectively, and large rapid depolarizations followed by less distinct prolonged depolarizations. The responsiveness on the two hemispheres to TRH and AcCho in mRNA-injected oocytes is opposite to that for the common intrinsic AcCho response in that there is a much greater response when agonist is applied at the animal rather than the vegetal hemisphere. We suggest that the differences in these responses are caused by differences in the intrinsic properties of these receptors. Because different receptors appear to be segregated in the same oocyte in distinct localizations, Xenopus oocytes may be an important model system in which to study receptor sorting in polarized cells.
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2012-01-01
Activated microglia exerts both beneficial and deleterious effects on neurons, but the signaling mechanism controlling these distinct responses remain unclear. We demonstrated that treatment of microglial cultures with the PAR-2 agonist, 2-Furoyl-LIGRLO-NH2, evoked early transient release of BDNF, while sustained PAR-2 stimulation evoked the delayed release of inflammatory cytokines (IL-1β and TNF-α) and nitric oxide. Culture medium harvested during the early phase (at 1 h) of microglial activation induced by 2-Furoyl-LIGRLO-NH2 (microglial conditioned medium, MCM) had no deleterious effects on cultured neurons, while MCM harvested during the late phase (at 72 h) promoted DNA fragmentation and apoptosis as indicated by TUNEL and annexin/PI staining. Blockade of PAR-1 during the early phase of PAR-2 stimulation enhanced BDNF release (by 11%, small but significant) while a PAR-1 agonist added during the late phase (24 h after 2-Furoyl-LIGRLO-NH2 addition) suppressed the release of cytokines and NO. The neuroprotective and neurotoxic effects of activated microglial exhibit distinct temporal profiles that are regulated by PAR-1 and PAR-2 stimulation. It may be possible to facilitate neuronal recovery and repair by appropriately timed stimulation and inhibition of microglial PAR-1 and PAR-2 receptors. PMID:22731117
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Kim, Kun-Hyung; Jun, Yong-Woo; Park, Yongsoo; Lee, Jin-A; Suh, Byung-Chang; Lim, Chae-Seok; Lee, Yong-Seok; Kaang, Bong-Kiun; Jang, Deok-Jin
2014-01-01
Phosphodiesterases (PDEs) play key roles in cAMP compartmentalization, which is required for intracellular signaling processes, through specific subcellular targeting. Previously, we showed that the long and short forms of Aplysia PDE4 (ApPDE4), which are localized to the membranes of distinct subcellular organelles, play key roles in 5-hydroxytryptamine-induced synaptic facilitation in Aplysia sensory and motor synapses. However, the molecular mechanism of the isoform-specific distinct membrane targeting was not clear. In this study, we further investigated the molecular mechanism of the membrane targeting of the ApPDE4 long and short forms. We found that the membrane targeting of the long form was mediated by hydrophobic interactions, mainly via 16 amino acids at the N-terminal region, whereas the short form was targeted solely to the plasma membrane, mainly by nonspecific electrostatic interactions between their N termini and the negatively charged lipids such as the phosphatidylinositol polyphosphates PI4P and PI(4,5)P2, which are embedded in the inner leaflet of the plasma membrane. Moreover, oligomerization of the long or short form by interaction of their respective upstream conserved region domains, UCR1 and UCR2, enhanced their plasma membrane targeting. These results suggest that the long and short forms of ApPDE4 are distinctly targeted to intracellular membranes through their direct association with the membranes via hydrophobic and electrostatic interactions, respectively. PMID:25077971
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Du, Dongxing; Jiang, Song; Wang, Ze; Hu, Yingying; He, Zhaoming
2014-01-01
Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER.
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Dynamic behavior of prosthetic aortic tissue valves as viewed by high-speed cinematography.
Rainer, W G; Christopher, R A; Sadler, T R; Hilgenberg, A D
1979-09-01
Using a valve testing apparatus of our own design and with a high-speed (600 to 800 frames per second) 16 mm movie camera, films were made of Hancock porcine, Carpentier-Edwards porcine, and Ionescu-Shiley bovine pericardial valves mounted in the aortic position and cycled under physiological conditions at 72 to 100 beats per minute. Fresh and explanted valves were observed using saline or 36.5% glycerol as the pumping solution. When fresh valves were studied using saline solution as the pumpint fluid, the Hancock and Carpentier-Edwards porcine valves showed high-frequency leaflet vibration, which increased in frequency with higher cycling rates. Abnormal leaflet motion was decreased when glycerol was used as the blood analogue. The Ionescu-Shiley bovine pericardial valve did not show abnormal leaflet motion under these conditions. Conclusions drawn from tissue valve testing studies that use excessively high pulsing rates and pressures (accelerated testing) and saline or water as pumping solutions cannot be transposed to predict the fate of tissue valves in a clinical setting.
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Tidholm, A; Nicolle, A P; Carlos, C; Gouni, V; Caruso, J L; Pouchelon, J L; Chetboul, V
2004-04-01
A mitral valve stenosis was diagnosed in a 2-year-old female Bull Terrier by use of two-dimensional (2-D) and M-mode echocardiography, colour-flow imaging and spectral Doppler examinations. Tissue Doppler Imaging was also performed to assess the segmental radial myocardial motion. The mitral valve stenosis was characterized by a decreased mitral orifice area/left ventricle area ratio (0.14), an increased early diastolic flow velocity (E wave = 1.9 m/s), a prolonged pressure half-time (106 ms) and a decreased E-F slope (4.5 cm/s) on pulsed-wave Doppler examination. This mitral stenosis was associated with an immobile posterior leaflet, as seen on 2-D and M-mode echocardiography. Immobility of the posterior mitral leaflet is considered to be a rare finding in humans and, to our knowledge, has not been precisely documented in dogs with mitral valve stenosis.
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Mitral valve plasty for mitral regurgitation after blunt chest trauma.
Kumagai, H; Hamanaka, Y; Hirai, S; Mitsui, N; Kobayashi, T
2001-06-01
A 21 year-old woman was admitted to our hospital because of chest and back pain after blunt chest trauma. On admission, consciousness was clear and a physical examination showed labored breathing. Her vital signs were stable, but her breathing gradually worsened, and artificial respiration was started. The chest roentgenogram and a subsequent chest computed tomographic scans revealed contusions, hemothorax of the left lung and multiple rib fractures. A transthoracic echocardiography (TTE) revealed normal left ventricular wall motion and mild mitral regurgitation (MR). TTE was carried out repeatedly, and revealed gradually progressive MR and prolapse of the posterior medial leaflet, although there was no congestive heart failure. After her general condition had recovered, surgery was performed. Intraoperative transesophageal echocardiography (TEE) revealed torn chordae at the posterior medial leaflet. The leaflet where the chorda was torn was cut and plicated, and posterior mitral annuloplasty was performed using a prosthetic ring. One month later following discharge, the MR had disappeared on TTE.
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Design of Bioprosthetic Aortic Valves using biaxial test data.
Dabiri, Y; Paulson, K; Tyberg, J; Ronsky, J; Ali, I; Di Martino, E; Narine, K
2015-01-01
Bioprosthetic Aortic Valves (BAVs) do not have the serious limitations of mechanical aortic valves in terms of thrombosis. However, the lifetime of BAVs is too short, often requiring repeated surgeries. The lifetime of BAVs might be improved by using computer simulations of the structural behavior of the leaflets. The goal of this study was to develop a numerical model applicable to the optimization of durability of BAVs. The constitutive equations were derived using biaxial tensile tests. Using a Fung model, stress and strain data were computed from biaxial test data. SolidWorks was used to develop the geometry of the leaflets, and ABAQUS finite element software package was used for finite element calculations. Results showed the model is consistent with experimental observations. Reaction forces computed by the model corresponded with experimental measurements when the biaxial test was simulated. As well, the location of maximum stresses corresponded to the locations of frequent tearing of BAV leaflets. Results suggest that BAV design can be optimized with respect to durability.
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Enzyme structures of the bacterial peptidoglycan and wall teichoic acid biogenesis pathways.
Caveney, Nathanael A; Li, Franco Kk; Strynadka, Natalie Cj
2018-06-06
The bacterial cell wall is a complex polymeric structure with essential roles in defence, survival and pathogenesis. Common to both Gram-positive and Gram-negative bacteria is the mesh-like peptidoglycan sacculus that surrounds the outer leaflet of the cytoplasmic membrane. Recent crystallographic studies of enzymes that comprise the peptidoglycan biosynthetic pathway have led to significant new understanding of all stages. These include initial multi-step cytosolic formation of sugar-pentapeptide precursors, transfer of the precursors to activated polyprenyl lipids at the membrane inner leaflet and flippase mediated relocalization of the resulting lipid II precursors to the outer leaflet where glycopolymerization and subsequent peptide crosslinking are finalized. Additional, species-specific enzymes allow customized peptidoglycan modifications and biosynthetic regulation that are important to bacterial virulence and survival. These studies have reinforced the unique and specific catalytic mechanisms at play in cell wall biogenesis and expanded the atomic foundation to develop novel, structure guided, antibacterial agents. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Pothineni, Koteswara R; Duncan, Kurt; Yelamanchili, Pridhvi; Nanda, Navin C; Patel, Vinod; Fan, PoHoey; Burri, Manjula V; Singh, Anurag; Panwar, Sadik R
2007-05-01
Twenty-nine patients with different tricuspid valve (TV) pathologies were studied by both two-dimensional transthoracic (2DTTE) and live/real time three-dimensional transthoracic echocardiography (3DTTE). A major contribution of 3DTTE over 2DTTE was the en face visualization of all three leaflets of the TV in all patients. This allowed accurate assessment of TV orifice area in patients with TV stenosis and carcinoid disease. Loss of TV leaflet tissue, defects in TV leaflets and size of TV systolic non-coaptation could also be delineated and resulted in identifying the mechanism of tricuspid regurgitation (TR) in patients with Ebstein's anomaly and rheumatic heart disease. Prolapse of TV leaflets could also be well visualized and enabled us to develop a schema for systematic assessment of individual segment prolapse which could help in surgical planning. The exact sites of chordae rupture in patients with flail TV as well as right ventricular papillary muscle rupture could be well seen by 3DTTE. 3DTTE also permitted sectioning of various TV masses for more specific diagnosis of their nature. In addition, color Doppler 3DTTE provided an estimate of quantitative evaluation of TR severity, since the exact shape and size of the vena contracta could be accurately assessed. In conclusion, our preliminary experience with 3DTTE has demonstrated substantial incremental value over 2DTTE in the assessment of various TV pathologies.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Qian, Shuo; Heller, William T
2011-01-01
Cellular membranes are complex mixtures of lipids, proteins, and other small molecules that provide functional, dynamic barriers between the cell and its environment, as well as between environments within the cell. The lipid composition of the membrane is highly specific and controlled in terms of both content and lipid localization. The membrane structure results from the complex interplay between the wide varieties of molecules present. Here, small-angle neutron scattering and selective deuterium labeling were used to probe the impact of the membrane-active peptides melittin and alamethicin on the structure of lipid bilayers composed of a mixture of the lipids dimyristoylmore » phosphatidylglycerol (DMPG) and chain-perdeuterated dimyristoyl phosphatidylcholine (DMPC). We found that both peptides enriched the outer leaflet of the bilayer with the negatively charged DMPG, creating an asymmetric distribution of lipids. The level of enrichment is peptide concentration-dependent and is stronger for melittin than it is for alamethicin. The enrichment between the inner and outer bilayer leaflets occurs at very low peptide concentrations and increases with peptide concentration, including when the peptide adopts a membrane-spanning, pore-forming state. The results suggest that these membrane-active peptides may have a secondary stressful effect on target cells at low concentrations that results from a disruption of the lipid distribution between the inner and outer leaflets of the bilayer that is independent of the formation of transmembrane pores.« less
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Sillence, D J; Raggers, R J; Neville, D C; Harvey, D J; van Meer, G
2000-08-01
In the present study, 2,2,6,6-tetramethylpiperidinooxy nitroxide (TEMPO) has been applied successfully to discriminate between glucosylceramide in the outer and inner leaflets of closed membrane bilayers. The nitroxyl radicals TEMPO and carboxy-TEMPO, once oxidized to nitrosonium ions, are capable of oxidizing residues that contain primary hydroxyl and amino groups. When applied to radiolabeled glucosylceramide in liposomes, oxidation with TEMPO led to an oxidized product that was easily separated from the original lipid by thin-layer chromatography, and that was identified by mass spectrometric analysis as the corresponding acid glucuronylceramide. To test whether oxidation was confined to the external leaflet, TEMPO was applied to large unilamellar vesicles (LUVs) consisting of egg phosphatidylcholine- egg phosphatidylethanolamine;-cholesterol 55:5:40 (mol/mol). TEMPO oxidized most radiolabeled phosphatidylethanolamine, whereas carboxy-TEMPO oxidized only half. Hydrolysis by phospholipase A(2) confirmed that 50% of the phosphatidylethanolamine was accessible in the external bilayer leaflet, suggesting that TEMPO penetrated the lipid bilayer and carboxy-TEMPO did not. When applied to LUVs containing <1 mol% radiolabeled glucosylceramide or short-chain C(6)-glucosylceramide, carboxy-TEMPO oxidized half the glucosylceramide. However, if surface C(6)-glucosylceramide was first depleted by bovine serum albumin (BSA) (extracting 49 +/- 1%), 94% of the remaining C(6)-glucosylceramide was resistant to oxidation. Carboxy-TEMPO oxidized glucosylceramide on the surface of LUVs without affecting inner leaflet glucosylceramide. At pH 9.5 and at 0 degrees C, the reaction reached completion by 20 min.
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How are service users instructed to measure home furniture for provision of minor assistive devices?
Atwal, Anita; Mcintyre, Anne; Spiliotopoulou, Georgia; Money, Arthur; Paraskevopulos, Ioannis
2017-02-01
Measurements play a vital role in providing devices that meet the individual needs of users. There is increasing evidence of devices being abandoned. The reasons for this are complex but one key factor that plays a role in non-use of equipment is the lack of fit between the device, environment and person. In addition, the abandonment of devices can be seen as a waste of public money. The aim of this paper is to examine the type, the readability, and the content of existing guidance in relation to measuring home furniture. An online national survey involving health and social care trusts in the UK. We conducted a synthesis of leaflets associated with measurement of furniture to identify existing guidance. The content and readability of this guidance was then evaluated. From the 325 responses received, 64 therapists reported using guidance. From the 13 leaflets that were analysed, 8 leaflets were found to meet Level 3 Adult Literacy Standards (age 9-11). There were differences in the way in which the measurement of furniture items occurred within the leaflets with no measurement guidance reported for baths. There is a need to standardize guidance to ensure that measurements are reliable. Implications for Rehabilitation Our research has highlighted the need to confirm and agree measurement techniques for home furniture in the provision of assistive devices. Inaccurate guidance can lead to abandonment of devices. Inaccurate guidance could prevent service users from not participating within the self-assessment process for devices.
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[Drug information for patients (Package Leaflets), and user testing in EU].
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.
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Cinosi, Vincenzo; Antonini, Roberto; Crateri, Pasqualina; Arancia, Giuseppe
2011-07-01
The plasma membrane lipid composition in AH-130 hepatoma cells was found to change remarkably after polyenylphosphatidylcholine (PPC) treatment. Plasma membranes from cells grown in rats treated for 7 days i.v. with 20 mg/kg/day PPC, when compared to those of control cells, did not show significantly different amounts of cholesterol or phospholipids relative to protein content, but, surprisingly, the individual phospholipid distribution inside the two membrane leaflets changed dramatically. Phosphatidylcholine (PC), the major phospholipid in the external membrane leaflet, increased ~47% (p<0.001). By contrast, phosphatidylethanolamine (PE), the most important component of the inner leaflet, decreased nearly 37% (p<0.001), while sphingomyelin (SM) also decreased ~17%, (p=0.1). Tumor cells collected from control rats at the same time interval and observed by scanning electron microscopy, exhibited a spherical shape with numerous and randomly distributed long microvilli, the same morphological and ultrastructural features displayed by the implanted cells. Conversely, tumor cells from PPC-treated rats no longer showed the roundish cell profile, and microvilli appeared shortened and enlarged, with the formation of surface blebs. Transmission electron microscopy observations confirmed the morphological and ultrastructural cell changes, mainly seen as loss of microvilli and intense cytoplasmic vacuolization. Taken together, these results indicate that the new phospholipid class distribution in the plasma membrane leaflets, modifying tumor cell viable structures, produced heavy cell damage and in many cases brought about complete cellular disintegration.
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Jang, Ki-Mo; Ahn, Jin Hwan; Wang, Joon Ho
2012-03-07
This article describes a case of an arthroscopic partial meniscectomy of a posteriorly flipped superior leaflet in a horizontal medial meniscus tear using the posterior transseptal portal. An arthroscopic partial meniscectomy for bucket handle or flap tears in medial or lateral compartments using ordinary portals is a relatively common procedure in irreparable cases. However, the posterior compartment of the knee is not readily accessible through ordinary arthroscopic portals. Therefore, it has been considered a blind spot. Through the posterior transseptal portal, surgeons can achieve excellent arthroscopic visualization of the posterior compartment and easily perform arthroscopic procedures of the posterior compartment of the knee. A 48-year-old woman presented with a 1-year history of pain in the medial aspect of the right knee joint. Preoperative magnetic resonance imaging revealed a thinning of the medial meniscus posterior horn in coronal images and a sharp-edged triangle arising from the medial meniscus posterior horn between the medial femoral condyle and medial meniscus posterior horn on sagittal images (flipped-over sign). During the arthroscopic procedure, we found that the flipped leaflet was displaced posteriorly and was not mobile between the medial femoral condyle and medial meniscus posterior horn. Partial meniscectomy for a posteriorly displaced fragment can be performed successfully using the posterior transseptal portal. The posterior transseptal portal is useful for an arthroscopic partial meniscectomy of a posteriorly flipped leaflet in the posterior compartment of the knee. Copyright 2012, SLACK Incorporated.
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Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide
Lam, Joseph S.; Taylor, Véronique L.; Islam, Salim T.; Hao, Youai; Kocíncová, Dana
2011-01-01
Lipopolysccharide (LPS) is an integral component of the Pseudomonas aeruginosa cell envelope, occupying the outer leaflet of the outer membrane in this Gram-negative opportunistic pathogen. It is important for bacterium–host interactions and has been shown to be a major virulence factor for this organism. Structurally, P. aeruginosa LPS is composed of three domains, namely, lipid A, core oligosaccharide, and the distal O antigen (O-Ag). Most P. aeruginosa strains produce two distinct forms of O-Ag, one a homopolymer of D-rhamnose that is a common polysaccharide antigen (CPA, formerly termed A band), and the other a heteropolymer of three to five distinct (and often unique dideoxy) sugars in its repeat units, known as O-specific antigen (OSA, formerly termed B band). Compositional differences in the O units among the OSA from different strains form the basis of the International Antigenic Typing Scheme for classification via serotyping of different strains of P. aeruginosa. The focus of this review is to provide state-of-the-art knowledge on the genetic and resultant functional diversity of LPS produced by P. aeruginosa. The underlying factors contributing to this diversity will be thoroughly discussed and presented in the context of its contributions to host–pathogen interactions and the control/prevention of infection. PMID:21687428
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Cross-Modulation of Homeostatic Responses to Temperature, Oxygen and Carbon Dioxide in C. elegans
Kodama-Namba, Eiji; Fenk, Lorenz A.; Bretscher, Andrew J.; Gross, Einav; Busch, K. Emanuel; de Bono, Mario
2013-01-01
Different interoceptive systems must be integrated to ensure that multiple homeostatic insults evoke appropriate behavioral and physiological responses. Little is known about how this is achieved. Using C. elegans, we dissect cross-modulation between systems that monitor temperature, O2 and CO2. CO2 is less aversive to animals acclimated to 15°C than those grown at 22°C. This difference requires the AFD neurons, which respond to both temperature and CO2 changes. CO2 evokes distinct AFD Ca2+ responses in animals acclimated at 15°C or 22°C. Mutants defective in synaptic transmission can reprogram AFD CO2 responses according to temperature experience, suggesting reprogramming occurs cell autonomously. AFD is exquisitely sensitive to CO2. Surprisingly, gradients of 0.01% CO2/second evoke very different Ca2+ responses from gradients of 0.04% CO2/second. Ambient O2 provides further contextual modulation of CO2 avoidance. At 21% O2 tonic signalling from the O2-sensing neuron URX inhibits CO2 avoidance. This inhibition can be graded according to O2 levels. In a natural wild isolate, a switch from 21% to 19% O2 is sufficient to convert CO2 from a neutral to an aversive cue. This sharp tuning is conferred partly by the neuroglobin GLB-5. The modulatory effects of O2 on CO2 avoidance involve the RIA interneurons, which are post-synaptic to URX and exhibit CO2-evoked Ca2+ responses. Ambient O2 and acclimation temperature act combinatorially to modulate CO2 responsiveness. Our work highlights the integrated architecture of homeostatic responses in C. elegans. PMID:24385919
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Heinrich, A; Andó, RD; Túri, G; Rózsa, B; Sperlágh, B
2012-01-01
BACKGROUND AND PURPOSE This study was undertaken to characterize the ATP, adenosine and glutamate outflow evoked by depolarization with high K+ concentrations, in slices of rat hippocampus. EXPERIMENTAL APPROACH We utilized the microelectrode biosensor technique and extracellular electrophysiological recording for the real-time monitoring of the efflux of ATP, adenosine and glutamate. KEY RESULTS ATP, adenosine and glutamate sensors exhibited transient and reversible current during depolarization with 25 mM K+, with distinct kinetics. The ecto-ATPase inhibitor ARL67156 enhanced the extracellular level of ATP and inhibited the prolonged adenosine efflux, suggesting that generation of adenosine may derive from the extracellular breakdown of ATP. Stimulation-evoked ATP, adenosine and glutamate efflux was inhibited by tetrodotoxin, while exposure to Ca2+-free medium abolished ATP and adenosine efflux from hippocampal slices. Extracellular elevation of ATP and adenosine were decreased in the presence of NMDA receptor antagonists, D-AP-5 and ifenprodil, whereas non-NMDA receptor blockade by CNQX inhibited glutamate but not ATP and adenosine efflux. The gliotoxin fluoroacetate and P2X7 receptor antagonists inhibited the K+-evoked ATP, adenosine and glutamate efflux, while carbenoxolone in low concentration and probenecid decreased only the adenosine efflux. CONCLUSIONS AND IMPLICATIONS Our results demonstrated activity-dependent gliotransmitter release in the hippocampus in response to ongoing neuronal activity. ATP and glutamate were released by P2X7 receptor activation into extracellular space. Although the increased extracellular levels of adenosine did derive from released ATP, adenosine might also be released directly via pannexin hemichannels. LINKED ARTICLE This article is commented on by Sershen, pp. 1000–1002 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2012.02072.x PMID:22394324
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Ware, Elizabeth A.; Gelman, Susan A.; Kleinberg, Felicia
2013-01-01
An important developmental task is learning to organize experience by forming conceptual relations among entities (e.g., a lion and a snake can be linked because both are animals; a lion and a cage can be linked because the lion lives in the cage). We propose that representational medium (i.e., pictures vs. objects) plays an important role in influencing which relations children consider. Prior work has demonstrated that pictures more readily evoke broader categories, whereas objects more readily call attention to specific individuals. We therefore predicted that pictures would encourage taxonomic and shared-property relations, whereas objects would encourage thematic and slot-filler relations. We observed 32 mother-child dyads (M child ages = 2.9 and 4.3) playing with pictures and objects, and identified utterances in which they made taxonomic, thematic, shared-property, or slot-filler links between items. The results confirmed our predictions and thus support representational medium as an important factor that influences the conceptual relations expressed during dyadic conversations. PMID:24273367
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Temporal Code-Driven Stimulation: Definition and Application to Electric Fish Signaling
Lareo, Angel; Forlim, Caroline G.; Pinto, Reynaldo D.; Varona, Pablo; Rodriguez, Francisco de Borja
2016-01-01
Closed-loop activity-dependent stimulation is a powerful methodology to assess information processing in biological systems. In this context, the development of novel protocols, their implementation in bioinformatics toolboxes and their application to different description levels open up a wide range of possibilities in the study of biological systems. We developed a methodology for studying biological signals representing them as temporal sequences of binary events. A specific sequence of these events (code) is chosen to deliver a predefined stimulation in a closed-loop manner. The response to this code-driven stimulation can be used to characterize the system. This methodology was implemented in a real time toolbox and tested in the context of electric fish signaling. We show that while there are codes that evoke a response that cannot be distinguished from a control recording without stimulation, other codes evoke a characteristic distinct response. We also compare the code-driven response to open-loop stimulation. The discussed experiments validate the proposed methodology and the software toolbox. PMID:27766078
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Karunarathne, W. K. Ajith; Giri, Lopamudra; Kalyanaraman, Vani; Gautam, N.
2013-01-01
G-protein–coupled receptor (GPCR) activity gradients evoke important cell behavior but there is a dearth of methods to induce such asymmetric signaling in a cell. Here we achieved reversible, rapidly switchable patterns of spatiotemporally restricted GPCR activity in a single cell. We recruited properties of nonrhodopsin opsins—rapid deactivation, distinct spectral tuning, and resistance to bleaching—to activate native Gi, Gq, or Gs signaling in selected regions of a cell. Optical inputs were designed to spatiotemporally control levels of second messengers, IP3, phosphatidylinositol (3,4,5)-triphosphate, and cAMP in a cell. Spectrally selective imaging was accomplished to simultaneously monitor optically evoked molecular and cellular response dynamics. We show that localized optical activation of an opsin-based trigger can induce neurite initiation, phosphatidylinositol (3,4,5)-triphosphate increase, and actin remodeling. Serial optical inputs to neurite tips can refashion early neuron differentiation. Methods here can be widely applied to program GPCR-mediated cell behaviors. PMID:23479634
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Temporal Code-Driven Stimulation: Definition and Application to Electric Fish Signaling.
Lareo, Angel; Forlim, Caroline G; Pinto, Reynaldo D; Varona, Pablo; Rodriguez, Francisco de Borja
2016-01-01
Closed-loop activity-dependent stimulation is a powerful methodology to assess information processing in biological systems. In this context, the development of novel protocols, their implementation in bioinformatics toolboxes and their application to different description levels open up a wide range of possibilities in the study of biological systems. We developed a methodology for studying biological signals representing them as temporal sequences of binary events. A specific sequence of these events (code) is chosen to deliver a predefined stimulation in a closed-loop manner. The response to this code-driven stimulation can be used to characterize the system. This methodology was implemented in a real time toolbox and tested in the context of electric fish signaling. We show that while there are codes that evoke a response that cannot be distinguished from a control recording without stimulation, other codes evoke a characteristic distinct response. We also compare the code-driven response to open-loop stimulation. The discussed experiments validate the proposed methodology and the software toolbox.
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Neuropharmacology of brain-stimulation-evoked aggression.
Siegel, A; Roeling, T A; Gregg, T R; Kruk, M R
1999-01-01
Evidence is reviewed concerning the brain areas and neurotransmitters involved in aggressive behavior in the cat and rodent. In the cat, two distinct neural circuits involving the hypothalamus and PAG subserve two different kinds of aggression: defensive rage and predatory (quiet-biting) attack. The roles played by the neurotransmitters serotonin, GABA, glutamate, opioids, cholecystokinin, substance P, norepinephrine, dopamine, and acetylcholine in the modulation and expression of aggression are discussed. For the rat, a single area, largely coincident with the intermediate hypothalamic area, is crucial for the expression of attack; variations in the rat attack response in natural settings are due largely to environmental variables. Experimental evidence emphasizing the roles of serotonin and GABA in modulating hypothalamically evoked attack in the rat is discussed. It is concluded that significant progress has been made concerning our knowledge of the circuitry underlying the neural basis of aggression. Although new and important insights have been made concerning neurotransmitter regulation of aggressive behavior, wide gaps in our knowledge remain.
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Orientation Tuning in the Visual Cortex of 3-Month-old Human Infants
Baker, Thomas J.; Norcia, Anthony M.; Candy, T. Rowan
2016-01-01
Sensitivity to orientation is critical for making a whole and complete picture of the world. We measured the orientation tuning of mechanisms inthe visual cortex of typically developing 3-month-olds and adults using a nonlinear analysis of the two-input steady-state visually evoked potential (VEP). Two gratings, one a fixed test and the other a variable orientation masker were tagged with distinct temporal frequencies and the corresponding evoked responses were measured at the harmonics of the test and masker frequencies and at a frequency equal to the sum of the two stimulus frequencies. The magnitude of the sum frequency component depended strongly on the relative orientation of the test and masker in both infants and adults. The VEP tuning bandwidths of the 3-month-olds measured at the sum frequency were similar to those of adults, suggesting that behavioral immaturities in functions such as orientation discrimination and contour integration may result from other immaturities in long-range lateral projections or feedback mechanisms. PMID:21236289
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Different states of synaptotagmin regulate evoked versus spontaneous release
Bai, Hua; Xue, Renhao; Bao, Huan; Zhang, Leili; Yethiraj, Arun; Cui, Qiang; Chapman, Edwin R.
2016-01-01
The tandem C2-domains of synaptotagmin 1 (syt) function as Ca2+-binding modules that trigger exocytosis; in the absence of Ca2+, syt inhibits spontaneous release. Here, we used proline linkers to constrain and alter the relative orientation of these C2-domains. Short poly-proline helices have a period of three, so large changes in the relative disposition of the C2-domains result from changing the length of the poly-proline linker by a single residue. The length of the linker was varied one residue at a time, revealing a periodicity of three for the ability of the linker mutants to interact with anionic phospholipids and drive evoked synaptic transmission; syt efficiently drove exocytosis when its tandem C2-domains pointed in the same direction. Analysis of spontaneous release revealed a reciprocal relationship between the activation and clamping activities of the linker mutants. Hence, different structural states of syt underlie the control of distinct forms of synaptic transmission. PMID:27001899
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Mapping social behavior-induced brain activation at cellular resolution in the mouse
Kim, Yongsoo; Venkataraju, Kannan Umadevi; Pradhan, Kith; Mende, Carolin; Taranda, Julian; Turaga, Srinivas C.; Arganda-Carreras, Ignacio; Ng, Lydia; Hawrylycz, Michael J.; Rockland, Kathleen; Seung, H. Sebastian; Osten, Pavel
2014-01-01
Understanding how brain activation mediates behaviors is a central goal of systems neuroscience. Here we apply an automated method for mapping brain activation in the mouse in order to probe how sex-specific social behaviors are represented in the male brain. Our method uses the immediate early gene c-fos, a marker of neuronal activation, visualized by serial two-photon tomography: the c-fos-GFP-positive neurons are computationally detected, their distribution is registered to a reference brain and a brain atlas, and their numbers are analyzed by statistical tests. Our results reveal distinct and shared female and male interaction-evoked patterns of male brain activation representing sex discrimination and social recognition. We also identify brain regions whose degree of activity correlates to specific features of social behaviors and estimate the total numbers and the densities of activated neurons per brain areas. Our study opens the door to automated screening of behavior-evoked brain activation in the mouse. PMID:25558063
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Cortical response variability as a developmental index of selective auditory attention
Strait, Dana L.; Slater, Jessica; Abecassis, Victor; Kraus, Nina
2014-01-01
Attention induces synchronicity in neuronal firing for the encoding of a given stimulus at the exclusion of others. Recently, we reported decreased variability in scalp-recorded cortical evoked potentials to attended compared with ignored speech in adults. Here we aimed to determine the developmental time course for this neural index of auditory attention. We compared cortical auditory-evoked variability with attention across three age groups: preschoolers, school-aged children and young adults. Results reveal an increased impact of selective auditory attention on cortical response variability with development. Although all three age groups have equivalent response variability to attended speech, only school-aged children and adults have a distinction between attend and ignore conditions. Preschoolers, on the other hand, demonstrate no impact of attention on cortical responses, which we argue reflects the gradual emergence of attention within this age range. Outcomes are interpreted in the context of the behavioral relevance of cortical response variability and its potential to serve as a developmental index of cognitive skill. PMID:24267508
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Distinct Mechanisms for Synchronization and Temporal Patterning of Odor-Encoding Neural Assemblies
NASA Astrophysics Data System (ADS)
MacLeod, Katrina; Laurent, Gilles
1996-11-01
Stimulus-evoked oscillatory synchronization of neural assemblies and temporal patterns of neuronal activity have been observed in many sensory systems, such as the visual and auditory cortices of mammals or the olfactory system of insects. In the locust olfactory system, single odor puffs cause the immediate formation of odor-specific neural assemblies, defined both by their transient synchronized firing and their progressive transformation over the course of a response. The application of an antagonist of ionotropic γ-aminobutyric acid (GABA) receptors to the first olfactory relay neuropil selectively blocked the fast inhibitory synapse between local and projection neurons. This manipulation abolished the synchronization of the odor-coding neural ensembles but did not affect each neuron's temporal response patterns to odors, even when these patterns contained periods of inhibition. Fast GABA-mediated inhibition, therefore, appears to underlie neuronal synchronization but not response tuning in this olfactory system. The selective desynchronization of stimulus-evoked oscillating neural assemblies in vivo is now possible, enabling direct functional tests of their significance for sensation and perception.
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Kumar, Gideon Praveen; Cui, Fangsen; Phang, Hui Qun; Su, Boyang; Leo, Hwa Liang; Hon, Jimmy Kim Fatt
2014-07-01
Percutaneous heart valve replacement is gaining popularity, as more positive reports of satisfactory early clinical experiences are published. However this technique is mostly used for the replacement of pulmonary and aortic valves and less often for the repair and replacement of atrioventricular valves mainly due to their anatomical complexity. While the challenges posed by the complexity of the mitral annulus anatomy cannot be mitigated, it is possible to design mitral stents that could offer good anchorage and support to the valve prosthesis. This paper describes four new Nitinol based mitral valve designs with specific features intended to address migration and paravalvular leaks associated with mitral valve designs. The paper also describes maximum possible crimpability assessment of these mitral stent designs using a crimpability index formulation based on the various stent design parameters. The actual crimpability of the designs was further evaluated using finite element analysis (FEA). Furthermore, fatigue modeling and analysis was also done on these designs. One of the models was then coated with polytetrafluoroethylene (PTFE) with leaflets sutured and put to: (i) leaflet functional tests to check for proper coaptation of the leaflet and regurgitation leakages on a phantom model and (ii) anchorage test where the stented valve was deployed in an explanted pig heart. Simulations results showed that all the stents designs could be crimped to 18F without mechanical failure. Leaflet functional test results showed that the valve leaflets in the fabricated stented valve coapted properly and the regurgitation leakage being within acceptable limits. Deployment of the stented valve in the explanted heart showed that it anchors well in the mitral annulus. Based on these promising results of the one design tested, the other stent models proposed here were also considered to be promising for percutaneous replacement of mitral valves for the treatment of mitral regurgitation, by virtue of their key features as well as effective crimping. These models will be fabricated and put to all the aforementioned tests before being taken for animal trials. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.
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Mohammadi, H; Klassen, R J; Wan, W-K
2008-10-01
Pyrolytic carbon mechanical heart valves (MHVs) are widely used to replace dysfunctional and failed heart valves. As the human heart beats around 40 million times per year, fatigue is the prime mechanism of mechanical failure. In this study, a finite element approach is implemented to develop a model for fatigue analysis of MHVs due to the impact force between the leaflet and the stent and cavitation in the aortic position. A two-step method to predict crack propagation in the leaflets of MHVs has been developed. Stress intensity factors (SIFs) are computed at a small initiated crack located on the leaflet edge (the worst case) using the boundary element method (BEM). Static analysis of the crack is performed to analyse the stress distribution around the front crack zone when the crack is opened; this is followed by a dynamic crack analysis to consider crack propagation using the finite element approach. Two factors are taken into account in the calculation of the SIFs: first, the effect of microjet formation due to cavitation in the vicinity of leaflets, resulting in water hammer pressure; second, the effect of the impact force between the leaflet and the stent of the MHVs, both in the closing phase. The critical initial crack length, the SIFs, the water hammer pressure, and the maximum jet velocity due to cavitation have been calculated. With an initial crack length of 35 microm, the fatigue life of the heart valve is greater than 60 years (i.e. about 2.2 x 10(9) cycles) and, with an initial crack length of 170 microm, the fatigue life of the heart valve would be around 2.5 years (i.e. about 9.1 x 10(7) cycles). For an initial crack length greater than 170 microm, there is catastrophic failure and fatigue cracking no longer occurs. A finite element model of fatigue analysis using Patran command language (PCL custom code) in MSC software can be used to evaluate the useful lifespan of MHVs. Similar methodologies can be extended to other medical devices under cyclic loads.
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Jones, Ray B; O'Connor, Anita; Brelsford, Jade; Parsons, Neil; Skirton, Heather
2012-03-29
Better use of e-health services by patients could improve outcomes and reduce costs but there are concerns about inequalities of access. Previous research in outpatients suggested that anonymous personal email support may help patients with long term conditions to use e-health, but recruiting earlier in their 'journey' may benefit patients more. This pilot study explored the feasibility and cost of recruiting patients for an e-health intervention in one primary care trust. The sample comprised 46 practices with total patient population of 250,000. We approached all practices using various methods, seeking collaboration to recruit patients via methods agreed with each practice. A detailed research diary was kept of time spent recruiting practices and patients. Researcher time was used to estimate costs. Patients who consented to participate were offered email support for their use of the Internet for health. Eighteen practices agreed to take part; we recruited 27 patients, most (23/27) from five practices. Practices agreed to recruit patients for an e-health intervention via waiting room leaflets (16), posters (16), practice nurses (15), doctors giving patients leaflets (5), a study website link (7), inclusion in planned mailshots (2), and a special mailshot to patients selected from practice computers (1). After low recruitment response we also recruited directly in five practices through research assistants giving leaflets to patients in waiting rooms. Ten practices recruited no patients. Those practices that were more difficult to recruit were less likely to recruit patients. Leaving leaflets for practice staff to distribute and placing posters in the practice were not effective in recruiting patients. Leaflets handed out by practice nurses and website links were more successful. The practice with lowest costs per patient recruited (£70) used a special mailshot to selected patients. Recruitment via general practice was not successful and was therefore expensive. Direct to consumer methods and recruitment of patients in outpatients to offer email support may be more cost effective. If recruitment in general practice is required, contacting practices by letter and email, not following up non-responding practices, and recruiting patients with selected conditions by special mailshot may be the most cost-effective approach.
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New graft sizing rings for aortic valve reimplantation procedures.
Jelenc, Matija; Jelenc, Blaž; Kneževic, Ivan; Klokocovnik, Tomislav
2018-01-01
The objective was to design sizing rings that would enable proper sizing of the graft in reimplantation procedures and to perform leaflet repair before graft implantation. The rings were designed in Autodesk Fusion 360 (San Rafael, CA, USA) and 3D printed using a commercial online 3D printing service. We designed incomplete rings with a low profile and complete rings with a high profile. The complete rings are best suited for reimplantation procedures, whereas low profile C rings are intended for isolated aortic valve repair, where the ascending aorta is not transected. The rings come in sizes corresponding to Vascutek Gelweave graft sizes (Vascutek Terumo, Renfrewshire, Scotland). The ring internal diameters are 5% larger than the designated ring sizes and account for the 5% stretch of the grafts when pressurized. Blades of the rings are placed at 20° intervals. The slits between the blades are designed in such a way that the commissural U-sutures, when put in place and under tension, will lock the ring in position. The rings were successfully used in 10 of our latest reimplantation procedures. After dissection of the aortic root, the commissures were suspended with U-stitches and then the ring was seated onto them. Complete leaflet repair with plication to achieve adequate effective height was then performed, followed by graft implantation. No additional leaflet repair was needed. The newly designed sizing rings enable proper sizing of the graft in reimplantation procedures and enable complete leaflet repair before graft implantation. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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Sigüenza, Julien; Pott, Desiree; Mendez, Simon; Sonntag, Simon J; Kaufmann, Tim A S; Steinseifer, Ulrich; Nicoud, Franck
2018-04-01
The complex fluid-structure interaction problem associated with the flow of blood through a heart valve with flexible leaflets is investigated both experimentally and numerically. In the experimental test rig, a pulse duplicator generates a pulsatile flow through a biomimetic rigid aortic root where a model of aortic valve with polymer flexible leaflets is implanted. High-speed recordings of the leaflets motion and particle image velocimetry measurements were performed together to investigate the valve kinematics and the dynamics of the flow. Large eddy simulations of the same configuration, based on a variant of the immersed boundary method, are also presented. A massively parallel unstructured finite-volume flow solver is coupled with a finite-element solid mechanics solver to predict the fluid-structure interaction between the unsteady flow and the valve. Detailed analysis of the dynamics of opening and closure of the valve are conducted, showing a good quantitative agreement between the experiment and the simulation regarding the global behavior, in spite of some differences regarding the individual dynamics of the valve leaflets. A multicycle analysis (over more than 20 cycles) enables to characterize the generation of turbulence downstream of the valve, showing similar flow features between the experiment and the simulation. The flow transitions to turbulence after peak systole, when the flow starts to decelerate. Fluctuations are observed in the wake of the valve, with maximum amplitude observed at the commissure side of the aorta. Overall, a very promising experiment-vs-simulation comparison is shown, demonstrating the potential of the numerical method. Copyright © 2017 John Wiley & Sons, Ltd.
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Chin, Christopher R.; Savidis, George; Brass, Abraham L.; Melikyan, Gregory B.
2014-01-01
Interferon-induced transmembrane proteins (IFITMs) inhibit infection of diverse enveloped viruses, including the influenza A virus (IAV) which is thought to enter from late endosomes. Recent evidence suggests that IFITMs block virus hemifusion (lipid mixing in the absence of viral content release) by altering the properties of cell membranes. Consistent with this mechanism, excess cholesterol in late endosomes of IFITM-expressing cells has been reported to inhibit IAV entry. Here, we examined IAV restriction by IFITM3 protein using direct virus-cell fusion assay and single virus imaging in live cells. IFITM3 over-expression did not inhibit lipid mixing, but abrogated the release of viral content into the cytoplasm. Although late endosomes of IFITM3-expressing cells accumulated cholesterol, other interventions leading to aberrantly high levels of this lipid did not inhibit virus fusion. These results imply that excess cholesterol in late endosomes is not the mechanism by which IFITM3 inhibits the transition from hemifusion to full fusion. The IFITM3's ability to block fusion pore formation at a post-hemifusion stage shows that this protein stabilizes the cytoplasmic leaflet of endosomal membranes without adversely affecting the lumenal leaflet. We propose that IFITM3 interferes with pore formation either directly, through partitioning into the cytoplasmic leaflet of a hemifusion intermediate, or indirectly, by modulating the lipid/protein composition of this leaflet. Alternatively, IFITM3 may redirect IAV fusion to a non-productive pathway, perhaps by promoting fusion with intralumenal vesicles within multivesicular bodies/late endosomes. PMID:24699674
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Yoshita, Katsushi; Tanaka, Taichiro; Kikuchi, Yuriko; Takebayashi, Toru; Chiba, Nagako; Tamaki, Junko; Miura, Katsuyuki; Kadowaki, Takashi; Okamura, Tomonori; Ueshima, Hirotsugu
2004-07-01
To examine the effectiveness of newly developed materials for providing health-related information to the worksite population, we compared the amount of attention that employees paid to the materials. Study subjects were 2,361 employees in six companies participating in an intervention program between 2002 and 2003. Three kinds of media were used as tools for providing health information: [1] Point Of Purchase advertising menus (POP menus) were placed on all tables in company restaurants, [2] posters were put on walls and [3] leaflets were distributed at health-related events. One year or more after the introduction of these media, we compared the amount of attention paid to each type of medium. Amongst the three types of media, the POP menu drew the most attention, although results were not consistent in all gender and company groups. Every piece of information provided by the POP menus was "always" or "almost always" read by 41% of the men and 51% of the women surveyed. The corresponding rate for posters was 30% in men and 32% in women. For leaflets, only 16% of men and 22% of women read almost all of the leaflets. More attention was paid to the POP menu when the sample was women, older, and ate at the company restaurant at least three times a week. The POP menu may provide health-related information to a broader range of people than posters and leaflets, therefore, it is an effective material for population strategy.
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Takeda, Miyoko; Yamagami, Kanako; Tanaka, Kazuma
2014-03-01
Phospholipid flippases translocate phospholipids from the exoplasmic to the cytoplasmic leaflet of cell membranes to generate and maintain phospholipid asymmetry. The genome of budding yeast encodes four heteromeric flippases (Drs2p, Dnf1p, Dnf2p, and Dnf3p), which associate with the Cdc50 family noncatalytic subunit, and one monomeric flippase Neo1p. Flippases have been implicated in the formation of transport vesicles, but the underlying mechanisms are largely unknown. We show here that overexpression of the phosphatidylserine synthase gene CHO1 suppresses defects in the endocytic recycling pathway in flippase mutants. This suppression seems to be mediated by increased cellular phosphatidylserine. Two models can be envisioned for the suppression mechanism: (i) phosphatidylserine in the cytoplasmic leaflet recruits proteins for vesicle formation with its negative charge, and (ii) phosphatidylserine flipping to the cytoplasmic leaflet induces membrane curvature that supports vesicle formation. In a mutant depleted for flippases, a phosphatidylserine probe GFP-Lact-C2 was still localized to endosomal membranes, suggesting that the mere presence of phosphatidylserine in the cytoplasmic leaflet is not enough for vesicle formation. The CHO1 overexpression did not suppress the growth defect in a mutant depleted or mutated for all flippases, suggesting that the suppression was dependent on flippase-mediated phospholipid flipping. Endocytic recycling was not blocked in a mutant lacking phosphatidylserine or depleted in phosphatidylethanolamine, suggesting that a specific phospholipid is not required for vesicle formation. These results suggest that flippase-dependent vesicle formation is mediated by phospholipid flipping, not by flipped phospholipids.
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NASA Astrophysics Data System (ADS)
Schoch, Rafael L.; Barel, Itay; Brown, Frank L. H.; Haran, Gilad
2018-03-01
Supported lipid bilayers (SLBs) have been studied extensively as simple but powerful models for cellular membranes. Yet, potential differences in the dynamics of the two leaflets of a SLB remain poorly understood. Here, using single particle tracking, we obtain a detailed picture of bilayer dynamics. We observe two clearly separate diffusing populations, fast and slow, that we associate with motion in the distal and proximal leaflets of the SLB, respectively, based on fluorescence quenching experiments. We estimate diffusion coefficients using standard techniques as well as a new method based on the blur of images due to motion. Fitting the observed diffusion coefficients to a two-leaflet membrane hydrodynamic model allows for the simultaneous determination of the intermonolayer friction coefficient and the substrate-membrane friction coefficient, without any prior assumptions on the strengths of the relevant interactions. Remarkably, our calculations suggest that the viscosity of the interfacial water confined between the membrane and the substrate is elevated by ˜104 as compared to bulk water. Using hidden Markov model analysis, we then obtain insight into the transbilayer movement of lipids. We find that lipid flip-flop dynamics are very fast, with half times in the range of seconds. Importantly, we find little evidence for membrane defect mediated lipid flip-flop for SLBs at temperatures well above the solid-to-liquid transition, though defects seem to be involved when the SLBs are cooled down. Our work thus shows that the combination of single particle tracking and advanced hydrodynamic modeling provides a powerful means to obtain insight into membrane dynamics.
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Berger, Bettina; Schwarz, Christiane; Heusser, Peter
2015-05-07
Decision-making during pregnancy regarding different options of care can be difficult, particularly when risks of intervention versus no intervention for mother and baby are unclear. Unbiased information and support for decision making may be beneficial in these situations. The management of normal pregnancies at and beyond term is an example of such a situation. In order to determine the need to develop an evidence-based decision aid this paper searches, analyses and appraises patient decision aids and patient information leaflets regarding care options in cases of late term and post-term pregnancies, including complementary and alternative medicine (CAM). A literature search was carried out in a variety of lay and medical databases. written information related to uncomplicated singleton pregnancies and targeted at lay people. Analysis and appraisal of included material by means of quality criteria was set up based on the International Patient Decision Aid Standards accounting for evidence-basing of CAM options. Inclusion of two decision aids and eleven leaflets from four decision aids and sixteen leaflets. One decision aid met the quality criteria almost completely, the other one only insufficiently despite providing some helpful information. Only one leaflet is of good quality, but cannot substitute a decision aid. There is an urgent need for the design of an evidence-based decision aid of good quality for late-term or post-term pregnancy, particularly in German language.
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Robotic artificial chordal replacement for repair of mitral valve prolapse.
Brunsting, Louis A; Rankin, J Scott; Braly, Kimberly C; Binford, Robert S
2009-07-01
Artificial chordal replacement (ACR) has emerged as a superior method of mitral valve repair with excellent early and late efficacy. It is also ideal to combine with robotic techniques for correction of mitral prolapse, and this article presents a current method of robotic Gore-Tex ACR. Patients with isolated posterior leaflet prolapse are approached with the fourth-generation DaVinci robotic system and endoaortic balloon occlusion. A pledgetted anchor stitch is placed in a papillary muscle, and a 2-o Gore-Tex suture is passed through the anchor pledget. After full annuloplasty ring placement, the Gore-Tex suture is woven into the prolapsing segment and positioned temporarily with robotic forceps. Chordal length is then "adjusted" by lengthening or shortening the temporary knot over 1-cm increments as the valve is tested by injection of cold saline into the ventricle. After achieving good leaflet position and valve competence, the chord is tied permanently. The "adjustable" ACR procedure preserves leaflet surface area and produces a competent valve in the majority of patients. Postoperative transesophageal echo shows a large surface area of coaptation. Patient recovery is facilitated by the minimally invasive approach, while long-term stability of similar open ACR techniques have been excellent with a 2% to 3% failure rate over 10 years of follow-up. Robotic Gore-Tex ACR without leaflet resection is a reproducible procedure that simplifies mitral repair for prolapse. The outcomes observed in early robotic applications have been excellent. It is suggested that most patients with simple prolapse might validly be approached in this manner.
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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.
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Sensory feedback from the urethra evokes state-dependent lower urinary tract reflexes in rat.
Danziger, Zachary C; Grill, Warren M
2017-08-15
The lower urinary tract is regulated by reflexes responsible for maintaining continence and producing efficient voiding. It is unclear how sensory information from the bladder and urethra engages differential, state-dependent reflexes to either maintain continence or promote voiding. Using a new in vivo experimental approach, we quantified how sensory information from the bladder and urethra are integrated to switch reflex responses to urethral sensory feedback from maintaining continence to producing voiding. The results demonstrate how sensory information regulates state-dependent reflexes in the lower urinary tract and contribute to our understanding of the pathophysiology of urinary retention and incontinence where sensory feedback may engage these reflexes inappropriately. Lower urinary tract reflexes are mediated by peripheral afferents from the bladder (primarily in the pelvic nerve) and the urethra (in the pudendal and pelvic nerves) to maintain continence or initiate micturition. If fluid enters the urethra at low bladder volumes, reflexes relax the bladder and evoke external urethral sphincter (EUS) contraction (guarding reflex) to maintain continence. Conversely, urethral flow at high bladder volumes, excites the bladder (micturition reflex) and relaxes the EUS (augmenting reflex). We conducted measurements in a urethane-anaesthetized in vivo rat preparation to characterize systematically the reflexes evoked by fluid flow through the urethra. We used a novel preparation to manipulate sensory feedback from the bladder and urethra independently by controlling bladder volume and urethral flow. We found a distinct bladder volume threshold (74% of bladder capacity) above which flow-evoked bladder contractions were 252% larger and evoked phasic EUS activation 2.6 times as often as responses below threshold, clearly demonstrating a discrete transition between continence (guarding) and micturition (augmenting) reflexes. Below this threshold urethral flow evoked tonic EUS activity, indicative of the guarding reflex, that was proportional to the urethral flow rate. These results demonstrate the complementary roles of sensory feedback from the bladder and urethra in regulating reflexes in the lower urinary tract that depend on the state of the bladder. Understanding the neural control of functional reflexes and how they are mediated by sensory information in the bladder and urethra will open new opportunities, especially in neuromodulation, to treat pathologies of the lower urinary tract. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.
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Junghöfer, Markus; Rehbein, Maimu Alissa; Maitzen, Julius; Schindler, Sebastian
2017-01-01
Abstract Humans have a remarkable capacity for rapid affective learning. For instance, using first-order US such as odors or electric shocks, magnetoencephalography (MEG) studies of multi-CS conditioning demonstrate enhanced early (<150 ms) and mid-latency (150–300 ms) visual evoked responses to affectively conditioned faces, together with changes in stimulus evaluation. However, particularly in social contexts, human affective learning is often mediated by language, a class of complex higher-order US. To elucidate mechanisms of this type of learning, we investigate how face processing changes following verbal evaluative multi-CS conditioning. Sixty neutral expression male faces were paired with phrases about aversive crimes (30) or neutral occupations (30). Post conditioning, aversively associated faces evoked stronger magnetic fields in a mid-latency interval between 220 and 320 ms, localized primarily in left visual cortex. Aversively paired faces were also rated as more arousing and more unpleasant, evaluative changes occurring both with and without contingency awareness. However, no early MEG effects were found, implying that verbal evaluative conditioning may require conceptual processing and does not engage rapid, possibly sub-cortical, pathways. Results demonstrate the efficacy of verbal evaluative multi-CS conditioning and indicate both common and distinct neural mechanisms of first- and higher-order multi-CS conditioning, thereby informing theories of associative learning. PMID:28008078
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Junghöfer, Markus; Rehbein, Maimu Alissa; Maitzen, Julius; Schindler, Sebastian; Kissler, Johanna
2017-04-01
Humans have a remarkable capacity for rapid affective learning. For instance, using first-order US such as odors or electric shocks, magnetoencephalography (MEG) studies of multi-CS conditioning demonstrate enhanced early (<150 ms) and mid-latency (150-300 ms) visual evoked responses to affectively conditioned faces, together with changes in stimulus evaluation. However, particularly in social contexts, human affective learning is often mediated by language, a class of complex higher-order US. To elucidate mechanisms of this type of learning, we investigate how face processing changes following verbal evaluative multi-CS conditioning. Sixty neutral expression male faces were paired with phrases about aversive crimes (30) or neutral occupations (30). Post conditioning, aversively associated faces evoked stronger magnetic fields in a mid-latency interval between 220 and 320 ms, localized primarily in left visual cortex. Aversively paired faces were also rated as more arousing and more unpleasant, evaluative changes occurring both with and without contingency awareness. However, no early MEG effects were found, implying that verbal evaluative conditioning may require conceptual processing and does not engage rapid, possibly sub-cortical, pathways. Results demonstrate the efficacy of verbal evaluative multi-CS conditioning and indicate both common and distinct neural mechanisms of first- and higher-order multi-CS conditioning, thereby informing theories of associative learning. © The Author (2016). Published by Oxford University Press.
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Yamada, Toru; Umeyama, Shinji; Matsuda, Keiji
2012-01-01
In conventional functional near-infrared spectroscopy (fNIRS), systemic physiological fluctuations evoked by a body's motion and psychophysiological changes often contaminate fNIRS signals. We propose a novel method for separating functional and systemic signals based on their hemodynamic differences. Considering their physiological origins, we assumed a negative and positive linear relationship between oxy- and deoxyhemoglobin changes of functional and systemic signals, respectively. Their coefficients are determined by an empirical procedure. The proposed method was compared to conventional and multi-distance NIRS. The results were as follows: (1) Nonfunctional tasks evoked substantial oxyhemoglobin changes, and comparatively smaller deoxyhemoglobin changes, in the same direction by conventional NIRS. The systemic components estimated by the proposed method were similar to the above finding. The estimated functional components were very small. (2) During finger-tapping tasks, laterality in the functional component was more distinctive using our proposed method than that by conventional fNIRS. The systemic component indicated task-evoked changes, regardless of the finger used to perform the task. (3) For all tasks, the functional components were highly coincident with signals estimated by multi-distance NIRS. These results strongly suggest that the functional component obtained by the proposed method originates in the cerebral cortical layer. We believe that the proposed method could improve the reliability of fNIRS measurements without any modification in commercially available instruments. PMID:23185590
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Engell, Andrew D; McCarthy, Gregory
2013-07-01
Neuroimaging research has identified several category-selective regions in visual cortex that respond most strongly when viewing an exemplar image from a preferred category, such as faces. Recent studies, however, have suggested a more complex pattern of activation that has been heretofore unrecognized, e.g., the presence of additional patches of activation to faces beyond the well-studied fusiform face area, and the activation of ostensible face selective regions by animate motion of non-biological forms. Here, we characterize the spatial pattern of brain activity evoked by viewing faces or biological motion in large fMRI samples (N>120). We create probabilistic atlases for both face and biological motion activation, and directly compare their spatial patterns of activation. Our findings support the suggestion that the fusiform face area is composed of at least two separable foci of activation. The face-evoked response in the fusiform and nearby ventral temporal cortex has good reliability across runs; however, we found surprisingly high variability in lateral brain regions by faces, and for all brain regions by biological motion, which had an overall much lower effect size. We found that faces and biological motion evoke substantially overlapping activation distributions in both ventral and lateral occipitotemporal cortices. The peaks of activation for these different categories within these overlapping regions were close but distinct. Copyright © 2013 Elsevier Inc. All rights reserved.
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Wang, Maosen; He, Yi; Sejnowski, Terrence J; Yu, Xin
2018-02-13
Astrocytic Ca 2+ -mediated gliovascular interactions regulate the neurovascular network in situ and in vivo. However, it is difficult to measure directly both the astrocytic activity and fMRI to relate the various forms of blood-oxygen-level-dependent (BOLD) signaling to brain states under normal and pathological conditions. In this study, fMRI and GCaMP-mediated Ca 2+ optical fiber recordings revealed distinct evoked astrocytic Ca 2+ signals that were coupled with positive BOLD signals and intrinsic astrocytic Ca 2+ signals that were coupled with negative BOLD signals. Both evoked and intrinsic astrocytic calcium signal could occur concurrently or respectively during stimulation. The intrinsic astrocytic calcium signal can be detected globally in multiple cortical sites in contrast to the evoked astrocytic calcium signal only detected at the activated cortical region. Unlike propagating Ca 2+ waves in spreading depolarization/depression, the intrinsic Ca 2+ spikes occurred simultaneously in both hemispheres and were initiated upon the activation of the central thalamus and midbrain reticular formation. The occurrence of the intrinsic astrocytic calcium signal is strongly coincident with an increased EEG power level of the brain resting-state fluctuation. These results demonstrate highly correlated astrocytic Ca 2+ spikes with bidirectional fMRI signals based on the thalamic regulation of cortical states, depicting a brain-state dependency of both astrocytic Ca 2+ and BOLD fMRI signals.
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Wig, Gagan S; Buckner, Randy L; Schacter, Daniel L
2009-05-01
Behavioral dissociations suggest that a single experience can separately influence multiple processing components. Here we used a repetition priming functional magnetic resonance imaging paradigm that directly contrasted the effects of stimulus and decision changes to identify the underlying brain systems. Direct repetition of stimulus features caused marked reductions in posterior regions of the inferior temporal lobe that were insensitive to whether the decision was held constant or changed between study and test. By contrast, prefrontal cortex showed repetition effects that were sensitive to the exact stimulus-to-decision mapping. Analysis of resting-state functional connectivity revealed that the dissociated repetition effects are embedded within distinct brain systems. Regions that were sensitive to changes in the stimulus correlated with perceptual cortices, whereas the decision changes attenuated activity in regions correlated with middle-temporal regions and a frontoparietal control system. These results thus explain the long-known dissociation between perceptual and conceptual components of priming by revealing how a single experience can separately influence distinct, concurrently active brain systems.
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Volumetric velocimetry downstream of a percutaneous heart valve
NASA Astrophysics Data System (ADS)
Raghav, Vrishank; Clifford, Christopher; Midha, Prem; Okafor, Ikechukwu; Thurow, Brian; Yoganathan, Ajit; Auburn University Collaboration; Georgia Institute of Technology Collaboration
2017-11-01
Transcatheter aortic valve replacement has emerged as a safe and effective treatment for severe, symptomatic aortic stenosis in intermediate or greater surgical risk patients. However, despite excellent short-term outcomes, improved imaging and awareness has led to the identification of leaflet thrombosis on the aortic side of the prosthesis. Upon implantation, the transcatheter heart valve (THV) becomes enclosed in the native aortic valve leaflet tissue dividing the native sinus into two regions - a smaller anatomical sinus and a neo-sinus. To understand the causes for thrombosis, plenoptic Particle Image Velocimetry (PIV) is used to investigate the pulsatile three-dimensional flow in the sinus and neo-sinus region of the THV. Experiments are conducted on both a real and a transparent THV model in a pulsatile flow loop capable of replicating physiological hemodynamics. Comparisons with planar PIV results demonstrate the feasibility of using Plenoptic PIV to study heart valve fluid dynamics. Large three-dimensional regions of low velocity magnitude and low viscous shear stress were observed near the heart valve which could increase particle residence time potentially leading to formation of clots the THV leaflet.
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Fluid-structure interaction analysis of the flow through a stenotic aortic valve
NASA Astrophysics Data System (ADS)
Maleki, Hoda; Labrosse, Michel R.; Durand, Louis-Gilles; Kadem, Lyes
2009-11-01
In Europe and North America, aortic stenosis (AS) is the most frequent valvular heart disease and cardiovascular disease after systemic hypertension and coronary artery disease. Understanding blood flow through an aortic stenosis and developing new accurate non-invasive diagnostic parameters is, therefore, of primarily importance. However, simulating such flows is highly challenging. In this study, we considered the interaction between blood flow and the valve leaflets and compared the results obtained in healthy valves with stenotic ones. One effective method to model the interaction between the fluid and the structure is to use Arbitrary Lagrangian-Eulerian (ALE) approach. Our two-dimensional model includes appropriate nonlinear and anisotropic materials. It is loaded during the systolic phase by applying pressure curves to the fluid domain at the inflow. For modeling the calcified stenotic valve, calcium will be added on the aortic side of valve leaflets. Such simulations allow us to determine the effective orifice area of the valve, one of the main parameters used clinically to evaluate the severity of an AS, and to correlate it with changes in the structure of the leaflets.
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Oki, T; Fukuda, N; Tabata, T; Yamada, H; Manabe, K; Fukuda, K; Abe, M; Iuchi, A; Ito, S
1997-03-01
We describe a patient with Ebstein's anomaly in whom Doppler echocardiography was used to clarify the mechanism responsible for 'sail sound' and tricuspid regurgitation associated with this condition. Phonocardiography revealed an additional early systolic heart sound, consisting of a first low-amplitude component (T1) and a second high-amplitude component (T2, 'sail sound'). In simultaneous recordings of the tricuspid valve motion using M mode echocardiography and phonocardiography, the closing of the tricuspid valve occurred with T1 which originated at the tip of the tricuspid leaflets, while T2 originated from the body of the tricuspid leaflets. Using color Doppler imaging, the tricuspid regurgitant signal was detected during pansystole, indicating a blue signal during the phase corresponding to T1 and a mosaic signal during the phase corresponding to T2 at end-systole. Thus, 'sail sound' in patients with Ebstein's anomaly is not simply a closing sound of the tricuspid valve, but a complex closing sound which includes a sudden stopping sound after the anterior and/or other tricuspid leaflets balloon out at systole.
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NASA Astrophysics Data System (ADS)
Kaiser, Alexander
2016-11-01
The mitral valve is one of four valves in the human heart. The valve opens to allow oxygenated blood from the lungs to fill the left ventricle, and closes when the ventricle contracts to prevent backflow. The valve is composed of two fibrous leaflets which hang from a ring. These leaflets are supported like a parachute by a system of strings called chordae tendineae. In this talk, I will describe a new computational model of the mitral valve. To generate geometry, general information comes from classical anatomy texts and the author's dissection of porcine hearts. An MRI image of a human heart is used to locate the tips of the papillary muscles, which anchor the chordae tendineae, in relation to the mitral ring. The initial configurations of the valve leaflets and chordae tendineae are found by solving solving an equilibrium elasticity problem. The valve is then simulated in fluid (blood) using the immersed boundary method over multiple heart cycles in a model valve tester. We aim to identify features and mechanisms that influence or control valve function. Support from National Science Foundation, Graduate Research Fellowship Program, Grant DGE 1342536.
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Swirling flow in bileaflet mechanical heart valve
NASA Astrophysics Data System (ADS)
Gataulin, Yakov A.; Khorobrov, Svyatoslav V.; Yukhnev, Andrey D.
2018-05-01
Bileaflet mechanical valves are most commonly used for heart valve replacement. Nowadays swirling blood flow is registered in different parts of the cardiovascular system: left ventricle, aorta, arteries and veins. In present contribution for the first time the physiological swirling flow inlet conditions are used for numerical simulation of aortic bileaflet mechanical heart valve hemodynamics. Steady 3-dimensional continuity and RANS equations are employed to describe blood motion. The Menter SST model is used to simulate turbulence effects. Boundary conditions are corresponded to systolic peak flow. The domain was discretized into hybrid tetrahedral and hexahedral mesh with an emphasis on wall boundary layer. A system of equations was solved in Ansys Fluent finite-volume package. Noticeable changes in the flow structure caused by inlet swirl are shown. The swirling flow interaction with the valve leaflets is analyzed. A central orifice jet changes its cross-section shape, which leads to redistribution of wall shear stress on the leaflets. Transvalvular pressure gradient and area-averaged leaflet wall shear stress increase. Physiological swirl intensity noticeably reduces downstream of the valve.
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Delgadillo, Jaime; Moreea, Omar; Murphy, Elizabeth; Ali, Shehzad; Swift, Joshua K
2015-12-01
To assess if telephone text message appointment reminders and orientation leaflets can increase the proportion of patients who attend brief interventions after being assessed as suitable for guided self-help following cognitive behavioral therapy principles. Attendance was operationally defined as having accessed at least 1 therapy appointment. A secondary outcome was the proportion of attenders who completed or dropped out of therapy. After initial assessment, 254 patients with depression and anxiety disorders were randomly assigned to 1 of 3 groups: (a) usual waitlist control, (b) leaflet, (c) leaflet plus text message. Differences in the proportions of patients who started and completed therapy across groups were assessed using chi-square and logistic regression analyses. Overall, 63% of patients in this sample attended therapy. Between-group differences were not significant for attendance, x(2) (2) = 3.94, p = .14, or completion rates, x(2) (2) = 2.98, p = .23. These results were not confounded by demographic or clinical characteristics. Low-cost strategies appear to make no significant difference to therapy attendance and completion rates. © 2015 Wiley Periodicals, Inc.
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Novel pathogenetic mechanisms and structural adaptations in ischemic mitral regurgitation.
Silbiger, Jeffrey J
2013-10-01
Ischemic mitral regurgitation (MR) is a common complication of myocardial infarction thought to result from leaflet tethering caused by displacement of the papillary muscles that occurs as the left ventricle remodels. The author explores the possibility that left atrial remodeling may also play a role in the pathogenesis of ischemic MR, through a novel mechanism: atriogenic leaflet tethering. When ischemic MR is hemodynamically significant, the left ventricle compensates by dilating to preserve forward output using the Starling mechanism. Left ventricular dilatation, however, worsens MR by increasing the mitral valve regurgitant orifice, leading to a vicious cycle in which MR begets more MR. The author proposes that several structural adaptations play a role in reducing ischemic MR. In contrast to the compensatory effects of left ventricular enlargement, these may reduce, rather than increase, its severity. The suggested adaptations involve the mitral valve leaflets, the papillary muscles, the mitral annulus, and the left ventricular false tendons. This review describes the potential role each may play in reducing ischemic MR. Therapies that exploit these adaptations are also discussed. Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.
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An experimental-computational analysis of MHV cavitation: effects of leaflet squeezing and rebound.
Makhijani, V B; Yang, H Q; Singhal, A K; Hwang, N H
1994-04-01
A combined experimental-computational study was performed to investigate the flow mechanics which could cause cavitation during the squeezing and rebounding phases of valve closure in the 29 mm mitral bileaflet Edwards-Duromedics (ED) mechanical heart valve (MHV). Leaflet closing motion was measured in vitro, and input into a computational fluid mechanics software package, CFD-ACE, to compute flow velocities and pressures in the small gap space between the occluder tip and valve housing. The possibility of cavitation inception was predicted when fluid pressures dropped below the saturated vapor pressure for blood plasma. The computational analysis indicated that cavitation is more likely to be induced during valve rebound rather than the squeezing phase of valve closure in the 29 mm ED-MHV. Also, there is a higher probability of cavitation at lower values of the gap width at the point of impact between the leaflet tip and housing. These predictions of cavitation inception are not likely to be significantly influenced by the water-hammer pressure gradient that develops during valve closure.
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[Communication prostheses and behavioral alignment in hospital leaflets].
Vasconcellos-Silva, Paulo Roberto; Rivera, Francisco Javier Uribe; Rozemberg, Brani
2003-08-01
Review was made of publications that describe experience with printed material distributed to the lay public in hospital institutions. From the 146 leaflets examined, those aimed at professionals or disabled people, thus leaving 75 papers that illustrate the present pattern for the rationality behind the production, use and evaluation of this type of resource. In a general manner, such leaflets invest in the power of "ideal printed information" to align behavior with the hospital's biomedical agenda. The underlying rationality that permeates them perceives the "perfect information package" as one that efficiently describes its technical content for the purpose of unidirectional persuasion, is up-to-date in relation to readability scales and embellished by graphic design, and emphasizes the priorities defined by the professionals. Such "communication prostheses" should be capable of electronic validation by means of software suitable for proportioning the "doses" to the subject matter. Information as a drug, cognitivism, the lack of research on message reception and the need for communicative action for the deconstruction of systems of closed thinking within the hospital environment have been discussed.
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Maekawa, Masashi; Fairn, Gregory D
2015-04-01
Cholesterol is an essential component of metazoan cellular membranes and it helps to maintain the structural integrity and fluidity of the plasma membrane. Here, we developed a cholesterol biosensor, termed D4H, based on the fourth domain of Clostridium perfringens theta-toxin, which recognizes cholesterol in the cytosolic leaflet of the plasma membrane and organelles. The D4H probe disassociates from the plasma membrane upon cholesterol extraction and after perturbations in cellular cholesterol trafficking. When used in combination with a recombinant version of the biosensor, we show that plasmalemmal phosphatidylserine is essential for retaining cholesterol in the cytosolic leaflet of the plasma membrane. In vitro experiments reveal that 1-stearoy-2-oleoyl phosphatidylserine can induce phase separation in cholesterol-containing lipid bilayers and shield cholesterol from cholesterol oxidase. Finally, the altered transbilayer distribution of cholesterol causes flotillin-1 to relocalize to endocytic organelles. This probe should be useful in the future to study pools of cholesterol in the cytosolic leaflet of the plasma membrane and organelles. © 2015. Published by The Company of Biologists Ltd.
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Shi, Zhaoyue; Wu, Ruiqi; Yang, Pai-Feng; Wang, Feng; Wu, Tung-Lin; Mishra, Arabinda; Chen, Li Min; Gore, John C
2017-05-16
Although blood oxygenation level-dependent (BOLD) fMRI has been widely used to map brain responses to external stimuli and to delineate functional circuits at rest, the extent to which BOLD signals correlate spatially with underlying neuronal activity, the spatial relationships between stimulus-evoked BOLD activations and local correlations of BOLD signals in a resting state, and whether these spatial relationships vary across functionally distinct cortical areas are not known. To address these critical questions, we directly compared the spatial extents of stimulated activations and the local profiles of intervoxel resting state correlations for both high-resolution BOLD at 9.4 T and local field potentials (LFPs), using 98-channel microelectrode arrays, in functionally distinct primary somatosensory areas 3b and 1 in nonhuman primates. Anatomic images of LFP and BOLD were coregistered within 0.10 mm accuracy. We found that the point spread functions (PSFs) of BOLD and LFP responses were comparable in the stimulus condition, and both estimates of activations were slightly more spatially constrained than local correlations at rest. The magnitudes of stimulus responses in area 3b were stronger than those in area 1 and extended in a medial to lateral direction. In addition, the reproducibility and stability of stimulus-evoked activation locations within and across both modalities were robust. Our work suggests that the intrinsic resolution of BOLD is not a limiting feature in practice and approaches the intrinsic precision achievable by multielectrode electrophysiology.
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Shi, Zhaoyue; Wu, Ruiqi; Yang, Pai-Feng; Wang, Feng; Wu, Tung-Lin; Mishra, Arabinda; Chen, Li Min; Gore, John C.
2017-01-01
Although blood oxygenation level-dependent (BOLD) fMRI has been widely used to map brain responses to external stimuli and to delineate functional circuits at rest, the extent to which BOLD signals correlate spatially with underlying neuronal activity, the spatial relationships between stimulus-evoked BOLD activations and local correlations of BOLD signals in a resting state, and whether these spatial relationships vary across functionally distinct cortical areas are not known. To address these critical questions, we directly compared the spatial extents of stimulated activations and the local profiles of intervoxel resting state correlations for both high-resolution BOLD at 9.4 T and local field potentials (LFPs), using 98-channel microelectrode arrays, in functionally distinct primary somatosensory areas 3b and 1 in nonhuman primates. Anatomic images of LFP and BOLD were coregistered within 0.10 mm accuracy. We found that the point spread functions (PSFs) of BOLD and LFP responses were comparable in the stimulus condition, and both estimates of activations were slightly more spatially constrained than local correlations at rest. The magnitudes of stimulus responses in area 3b were stronger than those in area 1 and extended in a medial to lateral direction. In addition, the reproducibility and stability of stimulus-evoked activation locations within and across both modalities were robust. Our work suggests that the intrinsic resolution of BOLD is not a limiting feature in practice and approaches the intrinsic precision achievable by multielectrode electrophysiology. PMID:28461461
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A convergent functional architecture of the insula emerges across imaging modalities.
Kelly, Clare; Toro, Roberto; Di Martino, Adriana; Cox, Christine L; Bellec, Pierre; Castellanos, F Xavier; Milham, Michael P
2012-07-16
Empirical evidence increasingly supports the hypothesis that patterns of intrinsic functional connectivity (iFC) are sculpted by a history of evoked coactivation within distinct neuronal networks. This, together with evidence of strong correspondence among the networks defined by iFC and those delineated using a variety of other neuroimaging techniques, suggests a fundamental brain architecture detectable across multiple functional and structural imaging modalities. Here, we leverage this insight to examine the functional organization of the human insula. We parcellated the insula on the basis of three distinct neuroimaging modalities - task-evoked coactivation, intrinsic (i.e., task-independent) functional connectivity, and gray matter structural covariance. Clustering of these three different covariance-based measures revealed a convergent elemental organization of the insula that likely reflects a fundamental brain architecture governing both brain structure and function at multiple spatial scales. While not constrained to be hierarchical, our parcellation revealed a pseudo-hierarchical, multiscale organization that was consistent with previous clustering and meta-analytic studies of the insula. Finally, meta-analytic examination of the cognitive and behavioral domains associated with each of the insular clusters obtained elucidated the broad functional dissociations likely underlying the topography observed. To facilitate future investigations of insula function across healthy and pathological states, the insular parcels have been made freely available for download via http://fcon_1000.projects.nitrc.org, along with the analytic scripts used to perform the parcellations. Copyright © 2012 Elsevier Inc. All rights reserved.
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Tricuspid and Mitral Valve Regurgitation with Bi-fascicular Block Following a Horse Kick.
Kokubun, Tomoki; Oikawa, Masayoshi; Ichijo, Yasuhiro; Matsumoto, Yoshiyuki; Yokokawa, Tetsuro; Nakazato, Kazuhiko; Sato, Yoshiyuki; Takase, Shinya; Shinjo, Hiroharu; Yokoyama, Hitoshi; Suzuki, Hitoshi; Saitoh, Shu-Ichi; Takeishi, Yasuchika
2018-06-01
A 40-year-old man was transferred to our hospital following an isolated horse kick injury to the anterior chest wall. The case showed bi-fascicular block, severe tricuspid valve regurgitation due to ruptured chordae tendineae of the anterior leaflet, moderate mitral valve regurgitation due to prolapse of mitral anterior leaflet, and hypokinetic motion of the inferior septal wall. Both tricuspid and mitral insufficiency were completely repaired by a surgical operation. Fortunately, these injuries were not fatal in this case, but the comprehensive assessment of cardiac damage and careful observation are important for managing patients with cardiac injury.
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Rahn, Elizabeth J.; Zvonok, Alexander M.; Thakur, Ganesh A.; Khanolkar, Atmaram D.; Makriyannis, Alexandros; Hohmann, Andrea G.
2009-01-01
Activation of cannabinoid CB2 receptors suppresses neuropathic pain induced by traumatic nerve injury. The present studies were conducted to evaluate the efficacy of cannabinoid CB2 receptor activation in suppressing painful peripheral neuropathy evoked by chemotherapeutic treatment with the anti-tumor agent paclitaxel. Rats received paclitaxel (2 mg/kg i.p. per day) on four alternate days to induce mechanical hypersensitivity (mechanical allodynia). Mechanical allodynia was defined as a lowering of the threshold for paw withdrawal to stimulation of the plantar hind paw surface with an electronic von Frey stimulator. Mechanical allodynia developed in paclitaxel-treated animals relative to groups receiving the cremophor: ethanol: saline vehicle at the same times. Two structurally distinct cannabinoid CB2 agonists—the aminoalkylindole (R,S)-AM1241 ((R,S)-(2-iodo-5-nitrophenyl)-[1-((1-methyl-piperidin-2-yl)methyl)-1H-indol-3-yl]-methanone) and the cannabilactone AM1714 (1,9-dihydroxy-3-(1′,1′-dimethylheptyl)-6H-benzo[c]chromene-6-one)—produced a dose-related suppression of established paclitaxel-evoked mechanical allodynia following systemic administration. Pretreatment with the CB2 antagonist SR144528 (5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-N-(1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl)-1H-pyrazole-3-carboxamide), but not the CB1 antagonist SR141716 (5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide), blocked the anti-allodynic effects of both (R,S)-AM1241 and AM1714. Moreover, (R)-AM1241, but not (S)-AM1241, suppressed paclitaxel-evoked mechanical allodynia relative to either vehicle treatment or pre-injection thresholds, consistent with mediation by CB2. Administration of either the CB1 or CB2 antagonist alone failed to alter paclitaxel-evoked mechanical allodynia. Moreover, (R,S)-AM1241 did not alter paw withdrawal thresholds in rats that received the cremophor vehicle in lieu of paclitaxel whereas AM1714 induced a modest antinociceptive effect. Our data suggest that cannabinoid CB2 receptors may be important therapeutic targets for the treatment of chemotherapy-evoked neuropathy. PMID:18664590
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Rahn, Elizabeth J; Zvonok, Alexander M; Thakur, Ganesh A; Khanolkar, Atmaram D; Makriyannis, Alexandros; Hohmann, Andrea G
2008-11-01
Activation of cannabinoid CB(2) receptors suppresses neuropathic pain induced by traumatic nerve injury. The present studies were conducted to evaluate the efficacy of cannabinoid CB(2) receptor activation in suppressing painful peripheral neuropathy evoked by chemotherapeutic treatment with the antitumor agent paclitaxel. Rats received paclitaxel (2 mg/kg i.p./day) on 4 alternate days to induce mechanical hypersensitivity (mechanical allodynia). Mechanical allodynia was defined as a lowering of the threshold for paw withdrawal to stimulation of the plantar hind paw surface with an electronic von Frey stimulator. Mechanical allodynia developed in paclitaxel-treated animals relative to groups receiving the Cremophor EL/ethanol/saline vehicle at the same times. Two structurally distinct cannabinoid CB(2) agonists, the aminoalkylindole (R,S)-AM1241 [(R,S)-(2-iodo-5-nitrophenyl)-[1-((1-methyl-piperidin-2-yl)methyl)-1H-indol-3-yl]-methanone] and the cannabilactone AM1714 (1,9-dihydroxy-3-(1',1'-dimethylheptyl)-6H-benzo[c]chromene-6-one), produced a dose-related suppression of established paclitaxel-evoked mechanical allodynia after systemic administration. Pretreatment with the CB(2) antagonist SR144528 [5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-N-(1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl)-1H-pyrazole-3-carboxamide], but not the CB(1) antagonist SR141716 [5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide], blocked the antiallodynic effects of both (R,S)-AM1241 and AM1714. Moreover, (R)-AM1241, but not (S)-AM1241, suppressed paclitaxel-evoked mechanical allodynia relative to either vehicle treatment or preinjection thresholds, consistent with mediation by CB(2). Administration of either the CB(1) or CB(2) antagonist alone failed to alter paclitaxel-evoked mechanical allodynia. Moreover, (R,S)-AM1241 did not alter paw withdrawal thresholds in rats that received the Cremophor EL vehicle in lieu of paclitaxel, whereas AM1714 induced a modest antinociceptive effect. Our data suggest that cannabinoid CB(2) receptors may be important therapeutic targets for the treatment of chemotherapy-evoked neuropathy.
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High-resolution mapping reveals topologically distinct cellular pools of phosphatidylserine
Fairn, Gregory D.; Schieber, Nicole L.; Ariotti, Nicholas; Murphy, Samantha; Kuerschner, Lars; Webb, Richard I.; Grinstein, Sergio
2011-01-01
Phosphatidylserine (PS) plays a central role in cell signaling and in the biosynthesis of other lipids. To date, however, the subcellular distribution and transmembrane topology of this crucial phospholipid remain ill-defined. We transfected cells with a GFP-tagged C2 domain of lactadherin to detect by light and electron microscopy PS exposed on the cytosolic leaflet of the plasmalemma and organellar membranes. Cytoplasmically exposed PS was found to be clustered on the plasma membrane, and to be associated with caveolae, the trans-Golgi network, and endocytic organelles including intraluminal vesicles of multivesicular endosomes. This labeling pattern was compared with the total cellular distribution of PS as visualized using a novel on-section technique. These complementary methods revealed PS in the interior of the ER, Golgi complex, and mitochondria. These results indicate that PS in the lumenal monolayer of the ER and Golgi complex becomes exposed cytosolically at the trans-Golgi network. Transmembrane flipping of PS may contribute to the exit of cargo from the Golgi complex. PMID:21788369
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Sadagopan, Shankar N; Veldtman, Gruschen R; Sivaprakasam, Muthukumaran C; Keeton, Barry R; Gnanapragasam, James P; Salmon, Anthony P; Haw, Marcus P; Vettukattil, Joseph J
2006-10-01
To define the anatomic characteristics of the congenitally malformed and severely stenotic aortic valve using trans-thoracic real time three-dimensional echocardiography, and to compare and contrast this with the valvar morphology as seen at surgery. Prospective cross-sectional observational study. Tertiary centre for paediatric cardiology. All patients requiring aortic valvotomy between December 2003 and July 2004 were evaluated prior to surgery with three-dimensional echocardiography. Full volume loop images were acquired using the Phillips Sonos 7500 system. A single observer analysed the images using "Q lab 4.1" software. The details were then compared with operative findings. We identified 8 consecutive patients, with a median age of 16 weeks, ranging from 1 day to 11 years, with median weight of 7.22 kilograms, ranging from 2.78 to 22 kilograms. The measured diameter of the valvar orifice, and the number of leaflets identified, corresponded closely with surgical assessment. The sites of fusion of the leaflets were correctly identified by the echocardiographic imaging in all cases. Fusion between the right and non-coronary leaflets was identified in half the patients. Dysplasia was observed in 3 patients, with 1 patient having nodules and 2 shown to have excrescences. At surgery, nodules were excised, and excrescences were trimmed. The dysplastic changes correlated well with operative findings, though statistically not significant. We recommend trans-thoracic real time three-dimensional echocardiography for the assessment of the congenitally malformed aortic valve, particularly to identify sites of fusion between leaflets and to measure the orificial diameter. The definition of nodularity, and the prognosis of nodules based on the mode of intervention, will need a comparative study of patients submitted to balloon dilation as well as those undergoing surgical valvotomy.
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Patients in need of medicine information.
Kazaryan, I; Sevikyan, A
2015-01-01
Reliable medicine information is important not only for physicians and pharmacists, but also for patients [6]. However, the results of studies implemented in some countries show that patients may have slightly different needs and preferences in using sources of information [1, 4, 5, 7]. The main objective of patient medicines information is assisting consumers to achieve safe and effective use of pharmaceuticals [2, 3]. To identify patients' needs in medicine information and sources they use to receive it. We interviewed 1059 people who had visited community pharmacies in 10 regions of Armenia and Yerevan. Previously developed questionnaire was used for interviewing patients. Statistical analysis was conducted using SPSS program. We found that consumers need medicine information. 68.9% of respondents often use pharmaceuticals only if necessary medicines information is available. The majority of them believe that it is important to have information about therapeutic indications of pharmaceuticals to be used (91.8%), their dosage and method of administration (91.1%), contraindications (82.4%), adverse reactions (81.9%) and the simultaneous use of multiple medicines (76.5%). 58.9% of consumers value information about medicine's price. More than 70% of patients often seek information from health professionals and use medicines package information leaflets (PIL), and more than 75% of respondents mainly trust the same sources. 71.5% of respondents read package leaflets, while 42.0% of consumers do this several times. Only 36.7% of respondents completely understand information in a leaflet. Patients in Armenia need medicine information. They prefer to receive information from sources they trust.Many patients do not understand the content of package information leaflets (PILs) due to barriers, which can be removed by introducing appropriate regulatory provisions for their content and readability.
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Patient-specific pediatric silicone heart valve models based on 3D ultrasound
NASA Astrophysics Data System (ADS)
Ilina, Anna; Lasso, Andras; Jolley, Matthew A.; Wohler, Brittany; Nguyen, Alex; Scanlan, Adam; Baum, Zachary; McGowan, Frank; Fichtinger, Gabor
2017-03-01
PURPOSE: Patient-specific heart and valve models have shown promise as training and planning tools for heart surgery, but physically realistic valve models remain elusive. Available proprietary, simulation-focused heart valve models are generic adult mitral valves and do not allow for patient-specific modeling as may be needed for rare diseases such as congenitally abnormal valves. We propose creating silicone valve models from a 3D-printed plastic mold as a solution that can be adapted to any individual patient and heart valve at a fraction of the cost of direct 3D-printing using soft materials. METHODS: Leaflets of a pediatric mitral valve, a tricuspid valve in a patient with hypoplastic left heart syndrome, and a complete atrioventricular canal valve were segmented from ultrasound images. A custom software was developed to automatically generate molds for each valve based on the segmentation. These molds were 3D-printed and used to make silicone valve models. The models were designed with cylindrical rims of different sizes surrounding the leaflets, to show the outline of the valve and add rigidity. Pediatric cardiac surgeons practiced suturing on the models and evaluated them for use as surgical planning and training tools. RESULTS: Five out of six surgeons reported that the valve models would be very useful as training tools for cardiac surgery. In this first iteration of valve models, leaflets were felt to be unrealistically thick or stiff compared to real pediatric leaflets. A thin tube rim was preferred for valve flexibility. CONCLUSION: The valve models were well received and considered to be valuable and accessible tools for heart valve surgery training. Further improvements will be made based on surgeons' feedback.
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Takewa, Yoshiaki; Yamanami, Masashi; Kishimoto, Yuichiro; Arakawa, Mamoru; Kanda, Keiichi; Matsui, Yuichi; Oie, Tomonori; Ishibashi-Ueda, Hatsue; Tajikawa, Tsutomu; Ohba, Kenkichi; Yaku, Hitoshi; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Nakayama, Yasuhide
2013-06-01
Using simple, safe, and economical in-body tissue engineering, autologous valved conduits (biovalves) with the sinus of Valsalva and without any artificial support materials were developed in animal recipients' bodies. In this study, the feasibility of the biovalve as an aortic valve was evaluated in a goat model. Biovalves were prepared by 2-month embedding of the molds, assembled using two types of specially designed plastic rods, in the dorsal subcutaneous spaces of goats. One rod had three projections, resembling the protrusions of the sinus of Valsalva. Completely autologous connective tissue biovalves (type VI) with three leaflets in the inner side of the conduit with the sinus of Valsalva were obtained after removing the molds from both terminals of the harvested implants with complete encapsulation. The biovalve leaflets had appropriate strength and elastic characteristics similar to those of native aortic valves; thus, a robust conduit was formed. Tight valvular coaptation and a sufficient open orifice area were observed in vitro. Biovalves (n = 3) were implanted in the specially designed apico-aortic bypass for 2 months as a pilot study. Postoperative echocardiography showed smooth movement of the leaflets with little regurgitation under systemic circulation (2.6 ± 1.1 l/min). α-SMA-positive cells appeared significantly with rich angiogenesis in the conduit and expanded toward the leaflet tip. At the sinus portions, marked elastic fibers were formed. The luminal surface was covered with thin pseudointima without thrombus formation. Completely autologous biovalves with robust and elastic characteristics satisfied the higher requirements of the systemic circulation in goats for 2 months with the potential for valvular tissue regeneration.
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Ovarian and cervical cancer awareness: development of two validated measurement tools.
Simon, Alice E; Wardle, Jane; Grimmett, Chloe; Power, Emily; Corker, Elizabeth; Menon, Usha; Matheson, Lauren; Waller, Jo
2012-07-01
The aim of the study was to develop and validate measures of awareness of symptoms and risk factors for ovarian and cervical cancer (Ovarian and Cervical Cancer Awareness Measures). Potentially relevant items were extracted from the literature and generated by experts. Four validation studies were carried out to establish reliability and validity. Women aged 21-67 years (n=146) and ovarian and cervical cancer experts (n=32) were included in the studies. Internal reliability was assessed psychometrically. Test-retest reliability was assessed over a 1-week interval. To establish construct validity, Cancer Awareness Measure (CAM) scores of cancer experts were compared with equally well-educated comparison groups. Sensitivity to change was tested by randomly assigning participants to read either a leaflet giving information about ovarian/cervical cancer or a leaflet with control information, and then completing the ovarian/cervical CAM. Internal reliability (Cronbach's α=0.88 for the ovarian CAM and α=0.84 for the cervical CAM) and test-retest reliability (r=0.84 and r=0.77 for the ovarian and cervical CAMs, respectively) were both high. Validity was demonstrated with cancer experts achieving higher scores than controls [ovarian CAM: t(36)= -5.6, p<0.001; cervical CAM: t(38)= -3.7, p=0.001], and volunteers who were randomised to read a cancer leaflet scored higher than those who received a control leaflet [ovarian CAM: t(49)=7.5, p<0.001; cervical CAM: t(48)= -5.5, p<0.001]. This study demonstrates the psychometric properties of the ovarian and cervical CAMs and supports their utility in assessing ovarian and cervical cancer awareness in the general population.
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Ovarian and cervical cancer awareness: development of two validated measurement tools
Simon, Alice E; Wardle, Jane; Grimmett, Chloe; Power, Emily; Corker, Elizabeth; Menon, Usha; Matheson, Lauren; Waller, Jo
2012-01-01
Background The aim of the study was to develop and validate measures of awareness of symptoms and risk factors for ovarian and cervical cancer (Ovarian and Cervical Cancer Awareness Measures). Methods Potentially relevant items were extracted from the literature and generated by experts. Four validation studies were carried out to establish reliability and validity. Women aged 21–67 years (n=146) and ovarian and cervical cancer experts (n=32) were included in the studies. Internal reliability was assessed psychometrically. Test-retest reliability was assessed over a 1-week interval. To establish construct validity, Cancer Awareness Measure (CAM) scores of cancer experts were compared with equally well-educated comparison groups. Sensitivity to change was tested by randomly assigning participants to read either a leaflet giving information about ovarian/cervical cancer or a leaflet with control information, and then completing the ovarian/cervical CAM. Results Internal reliability (Cronbach's α=0.88 for the ovarian CAM and α=0.84 for the cervical CAM) and test-retest reliability (r=0.84 and r=0.77 for the ovarian and cervical CAMs, respectively) were both high. Validity was demonstrated with cancer experts achieving higher scores than controls [ovarian CAM: t(36)= –5.6, p<0.001; cervical CAM: t(38)= –3.7, p=0.001], and volunteers who were randomised to read a cancer leaflet scored higher than those who received a control leaflet [ovarian CAM: t(49)=7.5, p<0.001; cervical CAM: t(48)= –5.5, p<0.001]. Conclusions This study demonstrates the psychometric properties of the ovarian and cervical CAMs and supports their utility in assessing ovarian and cervical cancer awareness in the general population. PMID:21933805
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Menciotti, G; Borgarelli, M; Aherne, M; Wesselowski, S; Häggström, J; Ljungvall, I; Lahmers, S M; Abbott, J A
2017-04-01
To assess differences in morphology of the mitral valve (MV) between healthy dogs and dogs affected by myxomatous mitral valve disease (MMVD) using real-time transthoracic three-dimensional echocardiography (RT3DE). Thirty-four were normal dogs and 79 dogs were affected by MMVD. Real-time transthoracic three-dimensional echocardiography mitral datasets were digitally recorded and analyzed using dedicated software. The following variables were obtained and compared between healthy dogs and dogs with MMVD at different stages: antero-posterior annulus diameter, anterolateral-posteromedial annulus diameter, commissural diameter, annulus height, annulus circumference, annulus area, anterior leaflet length, anterior leaflet area, posterior leaflet length, posterior leaflet area, non-planar angle, annulus sphericity index, tenting height, tenting area, tenting volume, the ratio of annulus height and commissural diameter. Dogs with MMVD had a more circular MV annulus compared to healthy dogs as demonstrated by an increased annulus sphericity index (p=0.0179). Affected dogs had a less saddle-shaped MV manifest as a decreased annulus height to commissural width ratio (p=0.0004). Tenting height (p<0.0001), area (p<0.0001), and volume (p<0.0001) were less in affected dogs. Real-time transthoracic three-dimensional echocardiography analysis demonstrated that dogs affected by MMVD had a more circular and less saddle-shaped MV annulus, as well as reduced tenting height area and volume, compared to healthy dogs. Multiple variables differed between dogs at different stages of MMVD. Diagnostic and prognostic utility of these variables, and the significance of these changes in the pathogenesis and natural history of MMVD, require further attention. Copyright © 2017 Elsevier B.V. All rights reserved.
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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.
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Shrestha, Anmol; Rajesh, V; Dessai, Sneha Shamrao; Stanly, Sharon Mary; Mateti, Uday Venkat
2018-05-25
Patient education is of paramount importance with regard to the condition of the disease and the treatment given besides lifestyle remodelling in order to get the desired therapeutic outcome. When verbal information is provided to the patients, they often tend to forget it. Pictorial aids or pictograms, as they are commonly known, are tools that are widely used for imparting knowledge to the patients. The aim of the study is to prepare and validate a Pictogram-based Patient Information Leaflet (P-PILs) on Tuberculosis (TB). P-PILs have been prepared from tertiary, secondary and primary sources. The knowledge-based questions are prepared with respect to the P-PILs. The baseline knowledge of the volunteers and patients have been analyzed before administering the P-PILs by using the validated questionnaire. The post-knowledge of the volunteers and patients has been analyzed after administering the P-PILs (20 min) by using the same questionnaire and the user-opinion has also been obtained at the end. The study results show that the mean scores of the overall user-testing knowledge assessment are found to have improved significantly from the pre-P-PILs administration score of 62.67 to the post-P-PILs administration score of 91. The overall user-opinion about the P-PILs has been found to be good (75%) followed by average (25%). The present study shows that there is significant improvement in the knowledge levels of the patients and volunteers after reading the validated leaflets. The Pictogram-based Patient Information Leaflets are found to be an effective educational tool for TB patients. Copyright © 2018. Published by Elsevier Ltd.
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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.
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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
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Phosphatidylserine directly and positively regulates fusion of myoblasts into myotubes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jeong, Jaemin, E-mail: jmj1103@kirams.re.kr; Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul; Conboy, Irina M., E-mail: iconboy@berkeley.edu
2011-10-14
Highlights: {yields} PS broadly and persistently trans-locates to the outer leaflet of plasma membrane during myoblast fusion into myotubes. {yields} Robust myotubes are formed when PS liposomes are added exogenously. {yields} PS increases the width of de novo myotubes and the numbers of myonuclei, but not the myotube length. {yields} Annexin V or PS antibody inhibits myotube formation by masking exposed PS. -- Abstract: Cell membrane consists of various lipids such as phosphatidylserine (PS), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). Among them, PS is a molecular marker of apoptosis, because it is located to the inner leaflet of plasma membrane generallymore » but it is moved to the outer leaflet during programmed cell death. The process of apoptosis has been implicated in the fusion of muscle progenitor cells, myoblasts, into myotubes. However, it remained unclear whether PS regulates muscle cell differentiation directly. In this paper, localization of PS to the outer leaflet of plasma membrane in proliferating primary myoblasts and during fusion of these myoblasts into myotubes is validated using Annexin V. Moreover, we show the presence of PS clusters at the cell-cell contact points, suggesting the importance of membrane ruffling and PS exposure for the myogenic cell fusion. Confirming this conclusion, experimentally constructed PS, but not PC liposomes dramatically enhance the formation of myotubes from myoblasts, thus demonstrating a direct positive effect of PS on the muscle cell fusion. In contrast, myoblasts exposed to PC liposomes produce long myotubes with low numbers of myonuclei. Moreover, pharmacological masking of PS on the myoblast surface inhibits fusion of these cells into myotubes in a dose-dependent manner.« less
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Morphometric features of the right atrioventricular orifice in adult human hearts.
Skwarek, M; Hreczecha, J; Dudziak, M; Jerzemowski, J; Szpinda, M; Grzybiak, M
2008-02-01
The normal data of the tricuspid valve complex is of great clinical importance in the light of progress in cardiosurgery and the development of novel operating techniques. A range of measurements for the right atrioventricular orifice in 96 human adult hearts was examined by means of anatomical dissection, inspection, examination, and statistical analyses. The length of the attachment of the anterior leaflet increased significantly between group I (aged 18-40 years) and group II (aged 41-64 years) in women only. In men there were no significant differences in this parameter between any of the three age groups. In addition, the attachment length of the posterior leaflet in women increased statistically in the second age group. In men, in contrast, the attachment length of the posterior leaflet did not increase significantly between the first and second age groups and became significantly larger only in oldest age group, consisting of men aged over 65. No statistically significant differences between the three age groups were found for the attachment length of the septal leaflet (p>0.05). In female hearts significant increases in the frontal and sagittal dimensions of the tricuspid valve orifice were observed between the second age group and the group aged over 65. In male hearts both the frontal and sagittal dimensions increased significantly with advanced age. The right atrioventricular orifice expressed as the ellipse area was statistically greater than the triangular area (p<0.01) in each age group. It should be noticed that both areas increased significantly during ageing. This study has demonstrated that the shape of the right atrioventricular orifice evolves during life, from a triangular shape to a more elliptical shape.
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Merle, Véronique; Marini, Hélène; Rongère, Julie; Tavolacci, Marie-Pierre; Scotté, Michel; Czernichow, Pierre
2011-06-01
A previous study suggested that most surgical patients do not remember having received information about surgical site infection (SSI). In other fields, written information has been suggested to improve patient satisfaction and recollection of information. Our objective was to assess if providing patients with written information about SSI, in addition to oral information, could influence patient satisfaction, recall of information, and opinion regarding SSI. A total of 207 patients scheduled for digestive surgery at a university hospital were randomized between usual oral information about SSI, plus an information leaflet about SSI (group O/L), or usual oral information alone (group O). Patients were interviewed 5 weeks after surgery to assess their recall and satisfaction regarding information, opinion regarding SSI, and declared intention of seeking legal action in case of SSI. Surgeons and interviewer were blinded to patients' group allocation. Recruitment occurred between October 2005 and August 2006. Of the original 207 patients, 161 patients (O/L=87, O=74) underwent operation and were interviewed as scheduled. Satisfaction was higher in group O/L (67% vs. O: 43%; P=0.003). The recall of having received information (O/L: 39% vs. O: 31%; P=0.29), was similar between the two groups. Judging SSI as always preventable was more frequent in group O/L (28% vs. O: 9%; P=0.004) with a trend toward a more frequent intention of seeking legal action (O/L: 10% vs. O: 3%; P=0.055). The leaflet did not improve patient recall of information about SSI, but it was associated with an increased level of satisfaction. The association between the leaflet and judging SSI as always preventable was unexpected.
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Kagiyama, Nobuyuki; Hayashida, Akihiro; Toki, Misako; Fukuda, Shota; Ohara, Minako; Hirohata, Atsushi; Yamamoto, Keizo; Isobe, Mitsuaki; Yoshida, Kiyoshi
2017-03-01
The relationship between annular dilatation caused by atrial fibrillation (AF) and mitral regurgitation (MR) remains controversial. We hypothesized that the small ratio of total leaflet area/annulus area (TLA/AA), reflecting insufficient leaflet remodeling to annular dilatation, is a main component of MR in patients with AF. Three-dimensional transesophageal echocardiographic data of the mitral valve were analyzed in 28 AF patients with moderate or severe MR (MR group), age- and sex-matched 56 AF patients with mild or less MR (non-MR group), and 16 control subjects. AA was significantly greater in both the MR (645±126 mm 2 /m 2 , P <0.001) and non-MR groups (568±121 mm 2 /m 2 , P =0.001) compared with control subjects (444±108 mm 2 /m 2 ). However, TLA/AA was significantly smaller in the MR (1.29±0.10, P <0.001), but not in the non-MR group (1.65±0.24, P >0.99), compared with control subjects (1.70±0.29). In linear regression analysis, TLA/AA was inversely associated with the effective regurgitant orifice ( r =-0.73, P <0.001). The area under the receiver-operating-characteristics curve of TLA/AA was significantly greater than that of AA (0.95 versus 0.72, P <0.001). Multivariable analysis revealed that small TLA/AA ( P <0.001) was independently associated with significant MR, while AA was not ( P =0.26). In patients with AF, insufficient leaflet remodeling to annular dilatation, rather than crude annular dilatation, was strongly associated with the severity of MR. © 2017 American Heart Association, Inc.
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Castelhano, João; Tavares, Paula; Mouga, Susana; Oliveira, Guiomar; Castelo-Branco, Miguel
2018-05-01
Electroencephalographic biomarkers have been widely investigated in autism, in the search for diagnostic, prognostic and therapeutic outcome measures. Here we took advantage of the information available in temporal oscillatory patterns evoked by simple perceptual decisions to investigate whether stimulus dependent oscillatory signatures can be used as potential biomarkers in autism spectrum disorder (ASD). We studied an extensive set of stimuli (9 categories of faces) and performed data driven classification (Support vector machine, SVM) of ASD vs. Controls with features based on the EEG power responses. We carried out an extensive time-frequency and synchrony analysis of distinct face categories requiring different processing mechanisms in terms of non-holistic vs. holistic processing. We found that the neuronal oscillatory responses of low gamma frequency band, locked to photographic and abstract two-tone (Mooney) face stimulus presentation are decreased in ASD vs. the control group. We also found decreased time-frequency (TF) responses in the beta band in ASD after 350 ms, possibly related to motor preparation. On the other hand, synchrony in the 30-45 Hz band showed a distinct spatial pattern in ASD. These power changes enabled accurate classification of ASD with an SVM approach. SVM accuracy was approximately 85%. ROC curves showed about 94% AUC (area under the curve). Combination of Mooney and Photographic face stimuli evoked features enabled a better separation between groups, reaching an AUC of 98.6%. We identified a relative decrease in EEG responses to face stimuli in ASD in the beta (15-30 Hz; >350 ms) and gamma (30-45 Hz; 55-80 Hz; 50-350 ms) frequency ranges. These can be used as input of a machine learning approach to separate between groups with high accuracy. Future studies can use EEG time-frequency patterns evoked by particular types of faces as a diagnostic biomarker and potentially as outcome measures in therapeutic trials. Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.
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Adaptive Acceleration of Visually Evoked Smooth Eye Movements in Mice
2016-01-01
The optokinetic response (OKR) consists of smooth eye movements following global motion of the visual surround, which suppress image slip on the retina for visual acuity. The effective performance of the OKR is limited to rather slow and low-frequency visual stimuli, although it can be adaptably improved by cerebellum-dependent mechanisms. To better understand circuit mechanisms constraining OKR performance, we monitored how distinct kinematic features of the OKR change over the course of OKR adaptation, and found that eye acceleration at stimulus onset primarily limited OKR performance but could be dramatically potentiated by visual experience. Eye acceleration in the temporal-to-nasal direction depended more on the ipsilateral floccular complex of the cerebellum than did that in the nasal-to-temporal direction. Gaze-holding following the OKR was also modified in parallel with eye-acceleration potentiation. Optogenetic manipulation revealed that synchronous excitation and inhibition of floccular complex Purkinje cells could effectively accelerate eye movements in the nasotemporal and temporonasal directions, respectively. These results collectively delineate multiple motor pathways subserving distinct aspects of the OKR in mice and constrain hypotheses regarding cellular mechanisms of the cerebellum-dependent tuning of movement acceleration. SIGNIFICANCE STATEMENT Although visually evoked smooth eye movements, known as the optokinetic response (OKR), have been studied in various species for decades, circuit mechanisms of oculomotor control and adaptation remain elusive. In the present study, we assessed kinematics of the mouse OKR through the course of adaptation training. Our analyses revealed that eye acceleration at visual-stimulus onset primarily limited working velocity and frequency range of the OKR, yet could be dramatically potentiated during OKR adaptation. Potentiation of eye acceleration exhibited different properties between the nasotemporal and temporonasal OKRs, indicating distinct visuomotor circuits underlying the two. Lesions and optogenetic manipulation of the cerebellum provide constraints on neural circuits mediating visually driven eye acceleration and its adaptation. PMID:27335412
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In Vivo Imaging of Diacylglycerol at the Cytoplasmic Leaflet of Plant Membranes.
Vermeer, Joop E M; van Wijk, Ringo; Goedhart, Joachim; Geldner, Niko; Chory, Joanne; Gadella, Theodorus W J; Munnik, Teun
2017-07-01
Diacylglycerol (DAG) is an important intermediate in lipid biosynthesis and plays key roles in cell signaling, either as a second messenger itself or as a precursor of phosphatidic acid. Methods to identify distinct DAG pools have proven difficult because biochemical fractionation affects the pools, and concentrations are limiting. Here, we validate the use of a genetically encoded DAG biosensor in living plant cells. The sensor is composed of a fusion between yellow fluorescent protein and the C1a domain of protein kinase C (YFP-C1aPKC) that specifically binds DAG, and was stably expressed in suspension-cultured tobacco BY-2 cells and whole Arabidopsis thaliana plants. Confocal imaging revealed that the majority of the YFP-C1aPKC fluorescence did not locate to membranes but was present in the cytosol and nucleus. Treatment with short-chain DAG or PMA (phorbol-12-myristate-13-acetate), a phorbol ester that binds the C1a domain of PKC, caused the recruitment of the biosensor to the plasma membrane. These results indicate that the biosensor works and that the basal DAG concentration in the cytoplasmic leaflet of membranes (i.e. accessible to the biosensor) is in general too low, and confirms that the known pools in plastids, the endoplasmic reticulum and mitochondria are located at the luminal face of these compartments (i.e. inaccessible to the biosensor). Nevertheless, detailed further analysis of different cells and tissues discovered four novel DAG pools, namely at: (i) the trans-Golgi network; (ii) the cell plate during cytokinesis; (iii) the plasma membrane of root epidermal cells in the transition zone, and (iv) the apex of growing root hairs. The results provide new insights into the spatiotemporal dynamics of DAG in plants and offer a new tool to monitor this in vivo. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.
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Sotuyo, Solange; Contreras-Jiménez, José Luis; Lewis, Gwilym P
2017-01-01
A new legume species from a seasonally dry forest of the Western Río Balsas Depression, in the states of Guerrero and Michoacán, Mexico, Erythrostemon guevarafeferii , is herein described and illustrated. The new species shows morphological affinities with Erythrostemon hintonii , from which it is distinguished in having fewer leaflets per pinna, mature leaflets disposed toward the upper half of the pinnae rachises, long inflorescences on curved slender peduncles, abundant red glands on its flowers and inflorescences, and its fruit glabrous with red stipitate glands at maturity. A taxonomic key to the Río Balsas Depression species of Erythrostemon is included.
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Malformation of the canine mitral valve complex.
Litu, S K; Tilley, L P
1975-09-15
Twenty-nine dogs, including 13 Great Danes and 5 German Shepherd Dogs and averaging 7.3 months age, were diagnosed clinically and radiographically as having mitral regurgitation. Alterations of the mitral valve complex included enlarged anulus; short thick leaflets, with an occasional cleft; short and stout or long and thin chordae tendineae; upward malposition of atrophic or hypertrophic papillary muscles; insertion of one papillary muscle directly into one or both leaflets; and diffuse endocardial fibrosis, occasionally with jet lesions in te left atrium. Other cardiac anomalies included dysplasia of the tricuspid valve (5 dogs), patent ductus afteriosus (2 dogs), aortic stenosis (2 dogs), and ventricular septal defect (1 dog).
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Ukpe, Idongesit Sunday
2008-01-01
Leprosy is still occurring in the Republic of South Africa, but it has been eliminated as a public health problem. The country's leprosy care and control program is being provided as a primary health-care program within the general health-care services. Maintaining health workers' leprosy knowledge and awareness at the primary health-care level is one of the program's goals. In one of the country's rural areas, the availability of good-quality leprosy poster and leaflets at primary health-care facilities has been shown to contribute significantly to maintaining health workers' leprosy knowledge and awareness.
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Durrant, Lisa A; Taylor, James; Thompson, Helen; Usher, Kim; Jackson, Debra
2018-05-17
The present study, drawn from a larger mixed-methods case study, provides insights into the health literacy of community-based patients with pressure injuries, and their carers, and critically analyzes the patient information resources available; crucial because health literacy is associated with patient care and outcomes for patients. Two datasets were used to better understand patient literacy in relation to pressure injury: (i) narratives from patients and carers; and (ii) analysis of patient education resources. Narratives were subject to content analysis and patient education resources available to the patients were analyzed drawing on the Simplified Measure of Gobbledygook, the National Health Service Toolkit for Producing Patient Resources, and compared to an internationally-advocated pressure injury leaflet. The study findings indicated that despite leaflets broadly meeting required production and content guidelines, patients appeared to poorly engage with these materials and demonstrated limited health literacy in relation to pressure injury. Although improvements in leaflet production and readability might be advantageous, emphasis should remain on quality patient-health-care professional relationships to enable tailored patient education that can enhance awareness and engagement with treatment and prevention interventions. © 2018 John Wiley & Sons Australia, Ltd.
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Whittaker, P J; Gollins, H J; Roaf, E J
2014-03-01
Infant male circumcision is practised by many groups for religious and cultural reasons. Prompted by a desire to minimize the complication rate and to help parents identify good quality providers, a quality assurance (QA) process for infant male circumcision providers has been developed in Greater Manchester. Local stakeholders agreed a set of minimum standards, and providers were invited to submit evidence of their practice in relation to these standards. In participation with parents, community groups, faith groups, healthcare staff and safeguarding partners, an information leaflet for parents was produced. Engagement work with local community groups, faith groups, providers and healthcare staff was vital to ensure that the resources are accessible to parents and that providers continue to engage in the process. Providers that met the QA standards have been listed on a local website. Details of the website are included in the information leaflet distributed by maternity services, health visitors, primary care and community and faith groups. The leaflet is available in seven languages. Local QA processes can be used to encourage and identify good practice and to support parents who need to access services outside the remit of the National Health Service.
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Cardiolipin Prevents Membrane Translocation and Permeabilization by Daptomycin*
Zhang, TianHua; Muraih, Jawad K.; Tishbi, Nasim; Herskowitz, Jennifer; Victor, Rachel L.; Silverman, Jared; Uwumarenogie, Stephanie; Taylor, Scott D.; Palmer, Michael; Mintzer, Evan
2014-01-01
Daptomycin is an acidic lipopeptide antibiotic that, in the presence of calcium, forms oligomeric pores on membranes containing phosphatidylglycerol. It is clinically used against various Gram-positive bacteria such as Staphylococcus aureus and Enterococcus species. Genetic studies have indicated that an increased content of cardiolipin in the bacterial membrane may contribute to bacterial resistance against the drug. Here, we used a liposome model to demonstrate that cardiolipin directly inhibits membrane permeabilization by daptomycin. When cardiolipin is added at molar fractions of 10 or 20% to membranes containing phosphatidylglycerol, daptomycin no longer forms pores or translocates to the inner membrane leaflet. Under the same conditions, daptomycin continues to form oligomers; however, these oligomers contain only close to four subunits, which is approximately half as many as observed on membranes without cardiolipin. The collective findings lead us to propose that a daptomycin pore consists of two aligned tetramers in opposite leaflets and that cardiolipin prevents the translocation of tetramers to the inner leaflet, thereby forestalling the formation of complete, octameric pores. Our findings suggest a possible mechanism by which cardiolipin may mediate resistance to daptomycin, and they provide new insights into the action mode of this important antibiotic. PMID:24616102
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Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes
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
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Messersmith, Reid E; Nusz, Greg J; Reed, Scott M
2013-12-19
Gold nanoparticles provide a template for preparing supported lipid layers with well-defined curvature. Here, we utilize the localized surface plasmon resonance (LSPR) of gold nanoparticles as a sensor for monitoring the preparation of lipid layers on nanoparticles. The LSPR is very sensitive to the immediate surroundings of the nanoparticle surface and it is used to monitor the coating of lipids and subsequent conversion of a supported bilayer to a hybrid membrane with an outer lipid leaflet and an inner leaflet containing hydrophobic alkanethiol. We demonstrate that both decanethiol and propanethiol are able to form hybrid membranes and that the membrane created over the shorter thiol can be stripped from the gold along with the lipid leaflet using β-mercaptoethanol. The sensitivity of the nanoparticle LSPR to the refractive index (RI) of its surroundings is greater when the shorter thiol is used (37.8 ± 1.5 nm per RI unit) than when the longer thiol is used (27.5 ± 0.5 nm per RI unit). Finally, C-reactive protein binding to the membrane is measured using this sensor allowing observation of both protein-membrane and nanoparticle-nanoparticle interactions without chemical labeling of protein or lipids.
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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
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Real-time 3D visualization of cellular rearrangements during cardiac valve formation
Pestel, Jenny; Ramadass, Radhan; Gauvrit, Sebastien; Helker, Christian; Herzog, Wiebke
2016-01-01
During cardiac valve development, the single-layered endocardial sheet at the atrioventricular canal (AVC) is remodeled into multilayered immature valve leaflets. Most of our knowledge about this process comes from examining fixed samples that do not allow a real-time appreciation of the intricacies of valve formation. Here, we exploit non-invasive in vivo imaging techniques to identify the dynamic cell behaviors that lead to the formation of the immature valve leaflets. We find that in zebrafish, the valve leaflets consist of two sets of endocardial cells at the luminal and abluminal side, which we refer to as luminal cells (LCs) and abluminal cells (ALCs), respectively. By analyzing cellular rearrangements during valve formation, we observed that the LCs and ALCs originate from the atrium and ventricle, respectively. Furthermore, we utilized Wnt/β-catenin and Notch signaling reporter lines to distinguish between the LCs and ALCs, and also found that cardiac contractility and/or blood flow is necessary for the endocardial expression of these signaling reporters. Thus, our 3D analyses of cardiac valve formation in zebrafish provide fundamental insights into the cellular rearrangements underlying this process. PMID:27302398
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Xu, Jia-Yi; Han, Yong-He; Chen, Yanshan; Zhu, Ling-Jia; Ma, Lena Q
2016-02-01
The ability of As-resistant endophytic bacteria in As transformation and plant growth promotion was determined. The endophytes were isolated from As-hyperaccumulator Pteris vittata (PV) after growing for 60 d in a soil containing 200 mg kg(-1) arsenate (AsV). They were isolated in presence of 10 mM AsV from PV roots, stems, and leaflets, representing 4 phyla and 17 genera. All endophytes showed at least one plant growth promoting characteristics including IAA synthesis, siderophore production and P solubilization. The root endophytes had higher P solubilization ability than the leaflet (60.0 vs. 18.3 mg L(-1)). In presence of 10 mM AsV, 6 endophytes had greater growth than the control, suggesting As-stimulated growth. Furthermore, root endophytes were more resistant to AsV while the leaflet endophytes were more tolerant to arsenite (AsIII), which corresponded to the dominant As species in PV tissues. Bacterial As resistance was positively correlated to their ability in AsV reduction but not AsIII oxidation. The roles of those endophytes in promoting plant growth and As resistance in P. vittata warrant further investigation. Published by Elsevier Ltd.
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Delaunay, Jean-Louis; Breton, Michelyne; Trugnan, Germain; Maurice, Michèle
2008-01-01
A commonly-used method for analysing raft membrane domains is based on their resistance to extraction by non-ionic detergents at 4 degrees C. However, the selectivity of different detergents in defining raft membrane domains has been questioned. We have compared the lipid composition of detergent-resistant membranes (DRMs) obtained after Triton X-100 or Lubrol WX extraction in MDCK cells in order to understand the differential effect of these detergents on membranes and their selectivity in solubilizing or not proteins. Both Lubrol and Triton DRMs were enriched with cholesterol over the lysate, thus exhibiting characteristics consistent with the properties of membrane rafts. However, the two DRM fractions differed considerably in the ratio between lipids of the inner and outer membrane leaflets. Lubrol DRMs were especially enriched with phosphatidylethanolamine, including polyunsaturated species with long fatty acyl chains. Lubrol and Triton DRMs also differed in the amount of raft transmembrane proteins and raft proteins anchored to the cytoplasmic leaflet. Our results suggest that the inner side of rafts is enriched with phosphatidylethanolamine and cholesterol, and is more solubilized by Triton X-100 than by Lubrol WX.
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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.
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Murdock, Kyle; Martin, Caitlin; Sun, Wei
2018-01-01
Flexure is an important mode of deformation for native and bioprosthetic heart valves. However, mechanical characterization of bioprosthetic leaflet materials has been done primarily through planar tensile testing. In this study, an integrated experimental and computational cantilever beam bending test was performed to characterize the flexural properties of glutaraldehyde-treated bovine and porcine pericardium of different thicknesses. A strain-invariant based structural constitutive model was used to model the pericardial mechanical behavior quantified through the bending tests of this study and the planar biaxial tests previously performed. The model parameters were optimized through an inverse finite element (FE) procedure in order to describe both sets of experimental data. The optimized material properties were implemented in FE simulations of transcatheter aortic valve (TAV) deformation. It was observed that porcine pericardium TAV leaflets experienced significantly more flexure than bovine when subjected to opening pressurization, and that the flexure may be overestimated using a constitutive model derived from purely planar tensile experimental data. Thus, modeling of a combination of flexural and biaxial tensile testing data may be necessary to more accurately describe the mechanical properties of pericardium, and to computationally investigate bioprosthetic leaflet function and design. Copyright © 2017 Elsevier Ltd. All rights reserved.
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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.
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Real-time 3D visualization of cellular rearrangements during cardiac valve formation.
Pestel, Jenny; Ramadass, Radhan; Gauvrit, Sebastien; Helker, Christian; Herzog, Wiebke; Stainier, Didier Y R
2016-06-15
During cardiac valve development, the single-layered endocardial sheet at the atrioventricular canal (AVC) is remodeled into multilayered immature valve leaflets. Most of our knowledge about this process comes from examining fixed samples that do not allow a real-time appreciation of the intricacies of valve formation. Here, we exploit non-invasive in vivo imaging techniques to identify the dynamic cell behaviors that lead to the formation of the immature valve leaflets. We find that in zebrafish, the valve leaflets consist of two sets of endocardial cells at the luminal and abluminal side, which we refer to as luminal cells (LCs) and abluminal cells (ALCs), respectively. By analyzing cellular rearrangements during valve formation, we observed that the LCs and ALCs originate from the atrium and ventricle, respectively. Furthermore, we utilized Wnt/β-catenin and Notch signaling reporter lines to distinguish between the LCs and ALCs, and also found that cardiac contractility and/or blood flow is necessary for the endocardial expression of these signaling reporters. Thus, our 3D analyses of cardiac valve formation in zebrafish provide fundamental insights into the cellular rearrangements underlying this process. © 2016. Published by The Company of Biologists Ltd.
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The closing behavior of mechanical aortic heart valve prostheses.
Lu, Po-Chien; Liu, Jia-Shing; Huang, Ren-Hong; Lo, Chi-Wen; Lai, Ho-Cheng; Hwang, Ned H C
2004-01-01
Mechanical artificial heart valves rely on reverse flow to close their leaflets. This mechanism creates regurgitation and water hammer effects that may form cavitations, damage blood cells, and cause thromboembolism. This study analyzes closing mechanisms of monoleaflet (Medtronic Hall 27), bileaflet (Carbo-Medics 27; St. Jude Medical 27; Duromedics 29), and trileaflet valves in a circulatory mock loop, including an aortic root with three sinuses. Downstream flow field velocity was measured via digital particle image velocimetry (DPIV). A high speed camera (PIVCAM 10-30 CCD video camera) tracked leaflet movement at 1000 frames/s. All valves open in 40-50 msec, but monoleaflet and bileaflet valves close in much less time (< 35 msec) than the trileaflet valve (>75 msec). During acceleration phase of systole, the monoleaflet forms a major and minor flow, the bileaflet has three jet flows, and the trileaflet produces a single central flow like physiologic valves. In deceleration phase, the aortic sinus vortices hinder monoleaflet and bileaflet valve closure until reverse flows and high negative transvalvular pressure push the leaflets rapidly for a hard closure. Conversely, the vortices help close the trileaflet valve more softly, probably causing less damage, lessening back flow, and providing a washing effect that may prevent thrombosis formation.
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Zhong, Qi; Zeng, Wenhua; Huang, Xiaoyang; Zhao, Xiaojia
2014-01-01
Systolic anterior motion of the mitral valve is an uncommon complication of mitral valve repair, which requires immediate supplementary surgical action. Edge-to-edge suture is considered as an effective technique to treat post-mitral valve repair systolic anterior motion by clinical researchers. However, the fundamentals and quantitative analysis are vacant to validate the effectiveness of the additional edge-to-edge surgery to repair systolic anterior motion. In the present work, finite element models were developed to simulate a specific clinical surgery for patients with posterior leaflet prolapse, so as to analyze the edge-to-edge technique quantificationally. The simulated surgery procedure concluded several actions such as quadrangular resection, mitral annuloplasty and edge-to-edge suture. And the simulated results were compared with echocardiography and measurement data of the patients under the mitral valve surgery, which shows good agreement. The leaflets model with additional edge-to-edge suture has a shorter mismatch length than that of the model merely under quadrangular resection and mitral annuloplasty actions at systole, which assures a better coaptation status. The stress on the leaflets after edge-to-edge suture is lessened as well.
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The Fluid Mechanics of Transcatheter Heart Valve Leaflet Thrombosis in the Neosinus.
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
2017-10-24
Transcatheter heart valve (THV) thrombosis has been increasingly reported. In these studies, thrombus quantification has been based on a 2-dimensional assessment of a 3-dimensional phenomenon. Postprocedural, 4-dimensional, volume-rendered CT data of patients with CoreValve, Evolut R, and SAPIEN 3 transcatheter aortic valve replacement enrolled in the RESOLVE study (Assessment of Transcatheter and Surgical Aortic Bioprosthetic Valve Dysfunction With Multimodality Imaging and Its Treatment with Anticoagulation) were included in this analysis. Patients on anticoagulation were excluded. SAPIEN 3 and CoreValve/Evolut R patients with and without hypoattenuated leaflet thickening were included to study differences between groups. Patients were classified as having THV thrombosis if there was any evidence of hypoattenuated leaflet thickening. Anatomic and THV deployment geometries were analyzed, and thrombus volumes were computed through manual 3-dimensional 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 (neosinus). SAPIEN 3 valves with leaflet thrombosis were on average 10% further expanded (by diameter) than those without (95.5±5.2% versus 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 finding was not seen in the SAPIEN 3. The in vitro analysis showed that a supraannular THV deployment resulted in a nearly 7-fold decrease in stagnation zone size (velocities <0.1 m/s) when compared with an intraannular deployment. In addition, the in vitro model indicated that the size of the stagnation zone increased as cardiac output decreased. Although transcatheter aortic valve replacement thrombosis is a multifactorial process involving foreign materials, patient-specific blood chemistry, and complex flow patterns, our study indicates that deployed THV geometry may have implications on the occurrence of thrombosis. In addition, a supraannular neosinus may reduce thrombosis risk because of reduced flow stasis. Although additional prospective studies are needed to further develop strategies for minimizing thrombus burden, these results may help identify patients at higher thrombosis risk and aid in the development of next-generation devices with reduced thrombosis risk. © 2017 American Heart Association, Inc.
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Oesch, Peter; Kool, Jan; Fernandez-Luque, Luis; Brox, Ellen; Evertsen, Gunn; Civit, Anton; Hilfiker, Roger; Bachmann, Stefan
2017-03-23
Improving mobility in elderly persons is a primary goal in geriatric rehabilitation. Self-regulated exercises with instruction leaflets are used to increase training volume but adherence is often low. Exergames may improve adherence. This study therefore compared exergames with self-regulated exercise using instruction leaflets. The primary outcome was adherence. Secondary outcomes were enjoyment, motivation and balance during walking. Design: single center parallel group non-blinded randomized controlled trial with central stratified randomization. center for geriatric inpatient rehabilitation. Included were patients over 65 with mobility restrictions who were able to perform self-regulated exercise. Patients were assigned to self-regulated exercise using a) exergames on Windows Kinect® (exergame group EG) or b) instruction leaflets (conventional group CG). During two 30 min sessions physical therapists instructed self-regulated exercise to be conducted twice daily during thirty minutes during ten working days. Patients reported adherence (primary outcome), enjoyment and motivation daily. Balance during walking was measured blind before and after the treatment phase with an accelerometer. Analysis was by intention to treat. Repeated measures mixed models and Cohen's d effect sizes (ES, moderate if >0.5, large if > 0.8) with 95% CIs were used to evaluate between-group effects over time. Alpha was set at 0.05. From June 2014 to December 2015 217 patients were evaluated and 54 included, 26 in the EG and 28 in the CG. Adverse effects were observed in two patients in the EG who stopped because of pain during exercising. Adherence was comparable at day one (38 min. in the EG and 42 min. in the CG) and significantly higher in the CG at day 10 (54 min. in the CG while decreasing to 28 min. in the EG, p = 0.007, ES 0.94, 0.39-0.151). Benefits favoring the CG were also observed for enjoyment (p = 0.001, ES 0.88, 0.32 - 1.44) and motivation (p = 0.046, ES 0.59, 0.05-1.14)). There was no between-group effect in balance during walking. Self-regulated exercise using instruction leaflets is superior to exergames regarding adherence, enjoyment and motivation in a geriatric inpatient rehabilitation setting. Effects were moderate to large. There was no between group difference in balance during walking. ClinicalTrials.gov, NCT02077049 , 6 February 2014.
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Ghanouni, Alex; Renzi, Cristina; Waller, Jo
2017-04-18
There is broad agreement that cancer screening invitees should know the risks and benefits of testing before deciding whether to participate. In organised screening programmes, a primary method of relaying this information is via leaflets provided at the time of invitation. Little is known about why individuals do not engage with this information. This study assessed factors associated with reading information leaflets provided by the three cancer screening programmes in England. A cross-sectional survey asked screening-eligible members of the general population in England about the following predictor variables: uptake of previous screening invitations, demographic characteristics, and 'decision-making styles' (i.e. the extent to which participants tended to make decisions in a way that was avoidant, rational, intuitive, spontaneous, or dependent). The primary outcome measures were the amount of the leaflet that participants reported having read at their most recent invitation, for any of the three programmes for which they were eligible. Associations between these outcomes and predictor variables were assessed using binary or ordinal logistic regression. After exclusions, data from 275, 309, and 556 participants were analysed in relation to the breast, cervical, and bowel screening programmes, respectively. Notable relationships included associations between regularity of screening uptake and reading (more of) the information leaflets for all programmes (e.g. odds ratio: 0.16 for participants who never/very rarely attended breast screening vs. those who always attended previously; p = .009). Higher rational decision-making scores were associated with reading more of the cervical and bowel screening leaflets (OR: 1.13, p < .0005 and OR: 1.11, p = .045, respectively). Information engagement was also higher for White British participants compared with other ethnic groups for breast (OR: 3.28, p = .008) and bowel (OR: 2.58, p = .015) information; an opposite relationship was observed for older participants (OR: 0.96, p = .048; OR: 0.92, p = .029). Interventions that increase screening uptake may also increase subsequent engagement with information. Future research could investigate how to improve engagement at initial invitations. There may also be scope to reduce barriers to accessing non-English information and alternative communication strategies may benefit participants who are less inclined to weigh up advantages and disadvantages as part of their decision-making.
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2012-01-01
Background Better use of e-health services by patients could improve outcomes and reduce costs but there are concerns about inequalities of access. Previous research in outpatients suggested that anonymous personal email support may help patients with long term conditions to use e-health, but recruiting earlier in their 'journey' may benefit patients more. This pilot study explored the feasibility and cost of recruiting patients for an e-health intervention in one primary care trust. Methods The sample comprised 46 practices with total patient population of 250,000. We approached all practices using various methods, seeking collaboration to recruit patients via methods agreed with each practice. A detailed research diary was kept of time spent recruiting practices and patients. Researcher time was used to estimate costs. Patients who consented to participate were offered email support for their use of the Internet for health. Results Eighteen practices agreed to take part; we recruited 27 patients, most (23/27) from five practices. Practices agreed to recruit patients for an e-health intervention via waiting room leaflets (16), posters (16), practice nurses (15), doctors giving patients leaflets (5), a study website link (7), inclusion in planned mailshots (2), and a special mailshot to patients selected from practice computers (1). After low recruitment response we also recruited directly in five practices through research assistants giving leaflets to patients in waiting rooms. Ten practices recruited no patients. Those practices that were more difficult to recruit were less likely to recruit patients. Leaving leaflets for practice staff to distribute and placing posters in the practice were not effective in recruiting patients. Leaflets handed out by practice nurses and website links were more successful. The practice with lowest costs per patient recruited (£70) used a special mailshot to selected patients. Conclusion Recruitment via general practice was not successful and was therefore expensive. Direct to consumer methods and recruitment of patients in outpatients to offer email support may be more cost effective. If recruitment in general practice is required, contacting practices by letter and email, not following up non-responding practices, and recruiting patients with selected conditions by special mailshot may be the most cost-effective approach. PMID:22458706