Compared efficacy of preservation solutions on the outcome of liver transplantation: Meta-analysis

PubMed Central

Szilágyi, Ágnes Lilla; Mátrai, Péter; Hegyi, Péter; Tuboly, Eszter; Pécz, Daniella; Garami, András; Solymár, Margit; Pétervári, Erika; Balaskó, Márta; Veres, Gábor; Czopf, László; Wobbe, Bastian; Szabó, Dorottya; Wagner, Juliane; Hartmann, Petra

2018-01-01

AIM To compare the effects of the four most commonly used preservation solutions on the outcome of liver transplantations. METHODS A systematic literature search was performed using MEDLINE, Scopus, EMBASE and the Cochrane Library databases up to January 31st, 2017. The inclusion criteria were comparative, randomized controlled trials (RCTs) for deceased donor liver (DDL) allografts with adult and pediatric donors using the gold standard University of Wisconsin (UW) solution or histidine-tryptophan-ketoglutarate (HTK), Celsior (CS) and Institut Georges Lopez (IGL-1) solutions. Fifteen RCTs (1830 livers) were included; the primary outcomes were primary non-function (PNF) and one-year post-transplant graft survival (OGS-1). RESULTS All trials were homogenous with respect to donor and recipient characteristics. There was no statistical difference in the incidence of PNF with the use of UW, HTK, CS and IGL-1 (RR = 0.02, 95%CI: 0.01-0.03, P = 0.356). Comparing OGS-1 also failed to reveal any difference between UW, HTK, CS and IGL-1 (RR = 0.80, 95%CI: 0.80-0.80, P = 0.369). Two trials demonstrated higher PNF levels for UW in comparison with the HTK group, and individual studies described higher rates of biliary complications where HTK and CS were used compared to the UW and IGL-1 solutions. However, the meta-analysis of the data did not prove a statistically significant difference: the UW, CS, HTK and IGL-1 solutions were associated with nearly equivalent outcomes. CONCLUSION Alternative solutions for UW yield the same degree of safety and effectiveness for the preservation of DDLs, but further well-designed clinical trials are warranted. PMID:29713134

A Comprehensive Analysis of the Phylogeny, Genomic Organization and Expression of Immunoglobulin Light Chain Genes in Alligator sinensis, an Endangered Reptile Species

PubMed Central

Lu, Yan; Zhang, Chenglin; Wu, Xiaobing; Han, Haitang; Zhao, Yaofeng; Ren, Liming

2016-01-01

Crocodilians are evolutionarily distinct reptiles that are distantly related to lizards and are thought to be the closest relatives of birds. Compared with birds and mammals, few studies have investigated the Ig light chain of crocodilians. Here, employing an Alligator sinensis genomic bacterial artificial chromosome (BAC) library and available genome data, we characterized the genomic organization of the Alligator sinensis IgL gene loci. The Alligator sinensis has two IgL isotypes, λ and κ, the same as Anolis carolinensis. The Igλ locus contains 6 Cλ genes, each preceded by a Jλ gene, and 86 potentially functional Vλ genes upstream of (Jλ-Cλ)n. The Igκ locus contains a single Cκ gene, 6 Jκs and 62 functional Vκs. All VL genes are classified into a total of 31 families: 19 Vλ families and 12 Vκ families. Based on an analysis of the chromosomal location of the light chain genes among mammals, birds, lizards and frogs, the data further confirm that there are two IgL isotypes in the Alligator sinensis: Igλ and Igκ. By analyzing the cloned Igλ/κ cDNA, we identified a biased usage pattern of V families in the expressed Vλ and Vκ. An analysis of the junctions of the recombined VJ revealed the presence of N and P nucleotides in both expressed λ and κ sequences. Phylogenetic analysis of the V genes revealed V families shared by mammals, birds, reptiles and Xenopus, suggesting that these conserved V families are orthologous and have been retained during the evolution of IgL. Our data suggest that the Alligator sinensis IgL gene repertoire is highly diverse and complex and provide insight into immunoglobulin gene evolution in vertebrates. PMID:26901135

Pituitary adenylate cyclase-activating peptide in the rat central nervous system: an immunohistochemical and in situ hybridization study.

PubMed

Hannibal, Jens

2002-11-25

In the present study the localization of pituitary adenylate cyclase-activating peptide (PACAP)-expressing cell bodies and PACAP projections were mapped in the adult rat brain and spinal cord by using immunohistochemistry and in situ hybridization histochemistry. A widespread occurrence of PACAP-containing cell bodies was found, with the greatest accumulation in several hypothalamic nuclei and in several brainstem nuclei, especially the habenular nuclei, the pontine nucleus, the lateral parabrachial nucleus (LPB), and the vagal complex. PACAP was also present in cell bodies in the olfactory areas, in neocortical areas, in the hippocampus, in the vestibulo- and cochlear nuclei, in cell bodies of the intermediolateral cell column of the spinal cord and in Purkinje cells of the cerebellum, in the subfornical organ, and in the organum vasculosum of the lamina terminalis. An intense accumulation of PACAP-immunoreactive (-IR) nerve fibers was observed throughout the hypothalamus, in the amydaloid and extended amygdaloid complex, in the anterior and paraventricular thalamic nuclei, in the intergeniculate leaflet, in the pretectum, and in several brainstem nuclei, such as the parabrachial nucleus, the sensory trigeminal nucleus, and the nucleus of the solitary tract. PACAP-IR nerve fibers were also found in the area postrema, the posterior pituitary and the choroid plexus, and the dorsal and ventral horn of the spinal cord. The widespread distribution of PACAP in the brain and spinal cord suggests that PACAP is involved in the control of many autonomic and sensory functions as well as higher cortical processes. Copyright 2002 Wiley-Liss, Inc.

Vesicular glutamate transporter 2 (VGLUT2) is co-stored with PACAP in projections from the rat melanopsin-containing retinal ganglion cells.

PubMed

Engelund, Anna; Fahrenkrug, Jan; Harrison, Adrian; Hannibal, Jens

2010-05-01

The retinal ganglion cell layer of the eye comprises a subtype of cells characterized by their intrinsic photosensitivity and expression of melanopsin (ipRGCs). These cells regulate a variety of non-image-forming (NIF) functions such as light entrainment of circadian rhythms, acute suppression of locomotor activity (masking), and pupillary light reflex. Two neurotransmitters have been identified in ipRGCs, glutamate and pituitary adenylate cyclase-activating polypeptide (PACAP). To date, little is known about their release and interplay. Here, we describe the presence and co-localization of vesicular glutamate transporter 2 (VGLUT2; a marker of glutamate signaling) and PACAP in ipRGCs and their projections in the brain. Nine adult male Wistar rats were assigned to one of three groups; anterograde tracing (n = 3), eye enucleation (n = 3), and untreated (n = 3). Under anaesthesia, rats were transcardially perfusion-fixated, after which the brains and eyes were removed for double immunohistochemical staining using a polyclonal anti-VGLUT2 antibody and a mouse monoclonal anti-PACAP antibody. Results revealed that VGLUT2- and PACAP-immunoreactivity (-ir) were present in ipRGCs and co-localized in their projections in the suprachiasmatic nucleus, the intergeniculate leaflet, and the olivary pretectal nucleus. We conclude that there is evidence to support the use of glutamate and PACAP as neurotransmitters in NIF photoperception by rat ipRGCs, and that these neurotransmitters are co-stored and probably released from the same nerve terminals. Furthermore, we conclude that VGLUT2 is the preferred subtype of vesicular transporter used by these cells.

A simple method for constructing the inhomogeneous quantum group IGLq(n) and its universal enveloping algebra Uq(igl(n))

NASA Astrophysics Data System (ADS)

Shariati, A.; Aghamohammadi, A.

1995-12-01

We propose a simple and concise method to construct the inhomogeneous quantum group IGLq(n) and its universal enveloping algebra Uq(igl(n)). Our technique is based on embedding an n-dimensional quantum space in an n+1-dimensional one as the set xn+1=1. This is possible only if one considers the multiparametric quantum space whose parameters are fixed in a specific way. The quantum group IGLq(n) is then the subset of GLq(n+1), which leaves the xn+1=1 subset invariant. For the deformed universal enveloping algebra Uq(igl(n)), we will show that it can also be embedded in Uq(gl(n+1)), provided one uses the multiparametric deformation of U(gl(n+1)) with a specific choice of its parameters.

Direct numerical simulations of temporally developing hydrocarbon shear flames at elevated pressure: effects of the equation of state and the unity Lewis number assumption

NASA Astrophysics Data System (ADS)

Korucu, Ayse; Miller, Richard

2016-11-01

Direct numerical simulations (DNS) of temporally developing shear flames are used to investigate both equation of state (EOS) and unity-Lewis (Le) number assumption effects in hydrocarbon flames at elevated pressure. A reduced Kerosene / Air mechanism including a semi-global soot formation/oxidation model is used to study soot formation/oxidation processes in a temporarlly developing hydrocarbon shear flame operating at both atmospheric and elevated pressures for the cubic Peng-Robinson real fluid EOS. Results are compared to simulations using the ideal gas law (IGL). The results show that while the unity-Le number assumption with the IGL EOS under-predicts the flame temperature for all pressures, with the real fluid EOS it under-predicts the flame temperature for 1 and 35 atm and over-predicts the rest. The soot mass fraction, Ys, is only under-predicted for the 1 atm flame for both IGL and real gas fluid EOS models. While Ys is over-predicted for elevated pressures with IGL EOS, for the real gas EOS Ys's predictions are similar to results using a non-unity Le model derived from non-equilibrium thermodynamics and real diffusivities. Adopting the unity Le assumption is shown to cause misprediction of Ys, the flame temperature, and the mass fractions of CO, H and OH.

GSK3β and VDAC Involvement in ER Stress and Apoptosis Modulation during Orthotopic Liver Transplantation

PubMed Central

Zaouali, Mohamed Amine; Panisello, Arnau; Lopez, Alexandre; Castro, Carlos; Folch, Emma; Carbonell, Teresa; Rolo, Anabela; Palmeira, Carlos Marques; Garcia-Gil, Agustin; Adam, René; Roselló-Catafau, Joan

2017-01-01

We investigated the involvement of glycogen synthase kinase-3β (GSK3β) and the voltage-dependent anion channel (VDAC) in livers subjected to cold ischemia–reperfusion injury (I/R) associated with orthotopic liver transplantation (OLT). Rat livers were preserved in University of Wisconsin (UW) and Institute Georges Lopez (IGL-1) solution, the latter enriched or not with trimetazidine, and then subjected to OLT. Transaminase (ALT) and HMGB1 protein levels, glutamate dehydrogenase (GLDH), and oxidative stress (MDA) were measured. The AKT protein kinase and its direct substrates, GSK3β and VDAC, as well as caspases 3, 9, and cytochrome C and reticulum endoplasmic stress-related proteins (GRP78, pPERK, ATF4, and CHOP), were determined by Western blot. IGL-1+TMZ significantly reduced liver injury. We also observed a significant phosphorylation of AKT, which in turn induced the phosphorylation and inhibition of GSK3β. In addition, TMZ protected the mitochondria since, in comparison with IGL-1 alone, we found reductions in VDAC phosphorylation, apoptosis, and GLDH release. All these results were correlated with decreased ER stress. Addition of TMZ to IGL-1 solution increased the tolerance of the liver graft to I/R injury through inhibition of GSK3β and VDAC, contributing to ER stress reduction and cell death prevention. PMID:28282906

Triple Immunoglobulin Gene Knockout Transchromosomic Cattle: Bovine Lambda Cluster Deletion and Its Effect on Fully Human Polyclonal Antibody Production

PubMed Central

Matsushita, Hiroaki; Sano, Akiko; Wu, Hua; Jiao, Jin-an; Kasinathan, Poothappillai; Sullivan, Eddie J.; Wang, Zhongde; Kuroiwa, Yoshimi

2014-01-01

Towards the goal of producing fully human polyclonal antibodies (hpAbs or hIgGs) in transchromosomic (Tc) cattle, we previously reported that Tc cattle carrying a human artificial chromosome (HAC) comprising the entire unrearranged human immunoglobulin (Ig) heavy-chain (hIGH), kappa-chain (hIGK), and lambda-chain (hIGL) germline loci produced physiological levels of hIgGs when both of the bovine immunoglobulin mu heavy-chains, bIGHM and bIGHML1, were homozygously inactivated (bIGHM−/−, bIGHML1−/−; double knockouts or DKO). However, because endogenous bovine immunoglobulin light chain loci are still intact, the light chains are produced both from the hIGK and hIGL genomic loci on the HAC and from the endogenous bovine kappa-chain (bIGK) and lambda-chain (bIGL) genomic loci, resulting in the production of fully hIgGs (both Ig heavy-chains and light-chains are of human origin: hIgG/hIgκ or hIgG/hIgλ) and chimeric hIgGs (Ig heavy-chains are of human origin while the Ig light-chains are of bovine origin: hIgG/bIgκ or hIgG/bIgλ). To improve fully hIgG production in Tc cattle, we here report the deletion of the entire bIGL joining (J) and constant (C) gene cluster (bIGLJ1-IGLC1 to bIGLJ5-IGLC5) by employing Cre/loxP mediated site-specific chromosome recombination and the production of triple knockout (bIGHM−/−, bIGHML1−/− and bIGL−/−; TKO) Tc cattle. We further demonstrate that bIGL cluster deletion greatly improves fully hIgGs production in the sera of TKO Tc cattle, with 51.3% fully hIgGs (hIgG/hIgκ plus hIgG/hIgλ). PMID:24603704

Retinal projections in the short-tailed fruit bat, Carollia perspicillata, as studied using the axonal transport of cholera toxin B subunit: Comparison with mouse.

PubMed

Scalia, Frank; Rasweiler, John J; Danias, John

2015-08-15

To provide a modern description of the Chiropteran visual system, the subcortical retinal projections were studied in the short-tailed fruit bat, Carollia perspicillata, using the anterograde transport of eye-injected cholera toxin B subunit, supplemented by the silver-impregnation of anterograde degeneration following eye removal, and compared with the retinal projections of the mouse. The retinal projections were heavily labeled by the transported toxin in both species. Almost all components of the murine retinal projection are present in Carollia in varying degrees of prominence and laterality. The projections: to the superior colliculus, accessory optic nuclei, and nucleus of the optic tract are predominantly or exclusively contralateral; to the dorsal lateral geniculate nucleus and posterior pretectal nucleus are predominantly contralateral; to the ventral lateral geniculate nucleus, intergeniculate leaflet, and olivary pretectal nucleus have a substantial ipsilateral component; and to the suprachiasmatic nucleus are symmetrically bilateral. The retinal projection in Carollia is surprisingly reduced at the anterior end of the dorsal lateral geniculate and superior colliculus, suggestive of a paucity of the relevant ganglion cells in the ventrotemporal retina. In the superior colliculus, in which the superficial gray layer is very thin, the projection is patchy in places where the layer is locally absent. Except for a posteriorly located lateral terminal nucleus, the other accessory optic nuclei are diminutive in Carollia, as is the nucleus of the optic tract. In both species the cholera toxin labeled sparse groups of apparently terminating axons in numerous regions not listed above. A question of their significance is discussed. © 2015 Wiley Periodicals, Inc.

Responses of the circadian system of rats to conditioned and unconditioned stimuli.

PubMed

de Groot, M H; Rusak, B

2000-08-01

The circadian systems of rodents respond to light pulses presented during the subjective night with phase shifts and altered cellular activity in the suprachiasmatic nuclei (SCN), including expression of immediate-early genes (IEGs) such as c-fos. A recent study showed that a nonphotic stimulus (an air disturbance generated by a fan) that does not normally induce the expression of c-fos-like immunoreactivity in the SCN of rats can be made to do so after being paired repeatedly with a light pulse in a Pavlovian conditioning paradigm. Furthermore, after conditioning (but not after noncontingent exposure to these stimuli), the fan also induced phase shifts in activity and body temperature rhythms comparable to those produced by light. The authors performed three experiments designed to replicate and extend these findings in rats. In experiment 1, rats were tested for conditioning effects of repeated pairings of a light pulse with a neutral air disturbance under a full photoperiod. In experiment 2, a modified conditioning paradigm was used in which a skeleton photoperiod served as both the entraining zeitgeber and the unconditioned stimulus. Animals in the paired and unpaired training conditions were exposed to both the light pulse and the air disturbance, but the air disturbance signaled the onset of light in the paired condition only. Phase shifts of wheel-running activity rhythms and gene expression in the SCN, intergeniculate leaflet, and paraventricular nucleus of the thalamus were assessed in animals following either of the training conditions or the control procedures. Experiment 3 assessed whether the air disturbance could entrain the circadian activity rhythms of rats with or without previous pairing with light in a classical conditioning paradigm. No evidence for classical conditioning, nor for unconditioned effects of the air disturbance on the circadian system, was found in these studies.

Comparison of insulin intensification strategies with insulin lispro low mixture twice daily versus basal insulin glargine and prandial insulin lispro once daily in East Asian and Caucasian patients with type 2 diabetes mellitus.

PubMed

Jeong, In-Kyung; Chung, Choon Hee; Zhou, Zhiguang; Han, Jeong Hee; Duan, Ran; Edralin, Diana M; Rodriguez, Angel

2017-04-01

This analysis evaluated efficacy and safety of insulin lispro low mixture (LM25) twice daily (breakfast and dinner) versus basal insulin glargine (bedtime) plus prandial insulin lispro (IGL) once daily before the largest meal in East Asian (EA) and Caucasian patients with type 2 diabetes mellitus who failed to reach glycemic targets on basal insulin glargine with metformin and/or pioglitazone. Included patients had an HbA1c ≥7.5% and ≤10.5% and fasting plasma glucose ≤6.7 mmol/L. Primary outcome was HbA1c change at 24 weeks. Baseline mean HbA1c was numerically similar between groups in EA (n = 79) and Caucasian (n = 278) patients. Mean (± SD) HbA1c decreased significantly from baseline to 24 weeks for LM25 and IGL in both subpopulations (EA: -1.32 ± 0.96% and -0.89 ± 0.96%; Caucasian: -1.24 ± 0.98% and -1.04 ± 0.97; all P < 0.0001). The respective proportions reaching HbA1c ≤7.0% at Week 24 in the LM25 and IGL groups were 33.3% and 22.9% (EA) and 37.2% and 34.1% (Caucasian). Mean (± SD) rates of hypoglycemia per 30 days in the LM25 and IGL groups were 0.74 ± 1.16 and 1.22 ± 1.36 (EA) and 1.38 ± 2.04 and 1.65 ± 2.43 (Caucasian). Mean (± SD) weight gain changes in the LM25 and IGL groups were 0.62 ± 2.78 and 0.51 ± 2.63 kg (EA) and 1.77 ± 2.91 and 0.67 ± 3.09 kg (Caucasian). Both strategies improved glycemic control in a small group of EA and Caucasian patients not adequately controlled on insulin glargine plus metformin and/or pioglitazone. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

On the nature of data collection for soft-tissue image-to-physical organ registration: a noise characterization study

NASA Astrophysics Data System (ADS)

Collins, Jarrod A.; Heiselman, Jon S.; Weis, Jared A.; Clements, Logan W.; Simpson, Amber L.; Jarnagin, William R.; Miga, Michael I.

2017-03-01

In image-guided liver surgery (IGLS), sparse representations of the anterior organ surface may be collected intraoperatively to drive image-to-physical space registration. Soft tissue deformation represents a significant source of error for IGLS techniques. This work investigates the impact of surface data quality on current surface based IGLS registration methods. In this work, we characterize the robustness of our IGLS registration methods to noise in organ surface digitization. We study this within a novel human-to-phantom data framework that allows a rapid evaluation of clinically realistic data and noise patterns on a fully characterized hepatic deformation phantom. Additionally, we implement a surface data resampling strategy that is designed to decrease the impact of differences in surface acquisition. For this analysis, n=5 cases of clinical intraoperative data consisting of organ surface and salient feature digitizations from open liver resection were collected and analyzed within our human-to-phantom validation framework. As expected, results indicate that increasing levels of noise in surface acquisition cause registration fidelity to deteriorate. With respect to rigid registration using the raw and resampled data at clinically realistic levels of noise (i.e. a magnitude of 1.5 mm), resampling improved TRE by 21%. In terms of nonrigid registration, registrations using resampled data outperformed the raw data result by 14% at clinically realistic levels and were less susceptible to noise across the range of noise investigated. These results demonstrate the types of analyses our novel human-to-phantom validation framework can provide and indicate the considerable benefits of resampling strategies.

Emulation of the laparoscopic environment for image-guided liver surgery via an abdominal phantom system with anatomical ligamenture

NASA Astrophysics Data System (ADS)

Heiselman, Jon S.; Collins, Jarrod A.; Clements, Logan W.; Weis, Jared A.; Simpson, Amber L.; Geevarghese, Sunil K.; Jarnagin, William R.; Miga, Michael I.

2017-03-01

In order to rigorously validate techniques for image-guided liver surgery (IGLS), an accurate mock representation of the intraoperative surgical scene with quantifiable localization of subsurface targets would be highly desirable. However, many attempts to reproduce the laparoscopic environment have encountered limited success due to neglect of several crucial design aspects. The laparoscopic setting is complicated by factors such as gas insufflation of the abdomen, changes in patient orientation, incomplete organ mobilization from ligaments, and limited access to organ surface data. The ability to accurately represent the influences of anatomical changes and procedural limitations is critical for appropriate evaluation of IGLS methodologies such as registration and deformation correction. However, these influences have not yet been comprehensively integrated into a platform usable for assessment of methods in laparoscopic IGLS. In this work, a mock laparoscopic liver simulator was created with realistic ligamenture to emulate the complexities of this constrained surgical environment for the realization of laparoscopic IGLS. The mock surgical system reproduces an insufflated abdominal cavity with dissectible ligaments, variable levels of incline matching intraoperative patient positioning, and port locations in accordance with surgical protocol. True positions of targets embedded in a tissue-mimicking phantom are measured from CT images. Using this setup, image-to-physical registration accuracy was evaluated for simulations of laparoscopic right and left lobe mobilization to assess rigid registration performance under more realistic laparoscopic conditions. Preliminary results suggest that non-rigid organ deformations and the region of organ surface data collected affect the ability to attain highly accurate registrations in laparoscopic applications.

Interaction of Francisella noatunensis subsp. orientalis with Oreochromis mossambicus bulbus arteriosus cell line

USGS Publications Warehouse

Soto, Esteban; Yun, Susan; Lewis, J.; Kearney, Michael T.; Hansen, John D.

2017-01-01

Francisella noatunensis subsp. orientalis (Fno) (syn. F. asiatica) is an emergent warmwater fish pathogen and the causative agent of piscine francisellosis. Although Fno causes septicemia and can live extracellularly in infected tilapia (Oreochromis spp.), the early interaction of Fno with vasculature endothelium is unknown. In the present study, we examined the interaction of wild-type Fno (WT) and two Fno knockout [intracellular growth loci C (ΔiglC) and pathogenicity determinant protein A (ΔpdpA)] strains with the endothelial O. mossambicus bulbus arteriosus cell line (TmB) at 25 °C and 30 °C. Similar amounts of WT, ΔiglC, and ΔpdpA attached and were detected intracellularly after 5 h of incubation at both temperatures; however temperature affected attachment and uptake. While significantly greater amounts of Fno (WT, ΔiglC, and ΔpdpA) were detected intracellularly when TmB cells were incubated at 30 °C, bacteria attached to TmBs at greater levels at 25 °C. Only WT Fno was able to replicate intracellularly at 25 °C, which resulted in Fno mediated cytotoxicity and apoptosis at 24 and 72 h post-infection. WT Fno incubated at 30 °C as well as ΔiglC,and ΔpdpA incubated at 25 °C and 30 °C were all defective for survival, replication, and the ability to cause cytotoxicity in TmB. Taken together, these results demonstrate that temperature plays a vital role for Fno intracellular survival, persistence and cytotoxicity.

Structural basis for human PECAM-1-mediated trans-homophilic cell adhesion

DOE PAGES

Hu, Menglong; Zhang, Hongmin; Liu, Qun; ...

2016-12-13

Cell adhesion involved in signal transduction, tissue integrity and pathogen infection is mainly mediated by cell adhesion molecules (CAM). One CAM member, platelet–endothelial-cell adhesion molecule-1 (PECAM-1), plays an important role in tight junction among endothelia cells, leukocyte trafficking, and immune response through its homophilic and heterophilic binding patterns. Both kinds of interactions, which lead to endogenous and exogenous signal transmission, are derived from extracellular immunoglobulin-like (IgL) domains and cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) of PECAM-1. To date, the mechanism of trans-homophilic interaction of PECAM-1 remains unclear. Here, we present the crystal structure of PECAM-1 IgL1-2 trans-homo dimer. Both IgLmore » 1 and 2 adopt the classical Ig domain conformation comprised of two layers of β-sheets possessing antiparallel β-strands with each being anchored by a pair of cysteines forming a disulfide bond. The dimer interface includes hydrophobic and hydrophilic interactions. The Small-Angle X-ray Scattering (SAXS) envelope of PECAM-1 IgL1-6 supported such a dimer formation in solution. As a result, cell adhesion assays on wildtype and mutant PECAM-1 further characterized the structural determinants in cell junction and communication.« less

Performance Audit of the U.S. Geological Survey, Energy Resource Program Inorganic Geochemistry Laboratory

USGS Publications Warehouse

Luppens, James A.; Janke, Louis G.; McCord, Jamey D.; Bullock, John H.; Brazeau, Lisa; Affronter, Ronald H.

2007-01-01

A performance audit of the U.S. Geological Survey (USGS), Energy Resource Program (ERP) Inorganic Geochemistry Laboratory (IGL) was conducted between August, 2003 and October, 2005. The goals were to ensure that a high level of analytical performance was maintained and identify any areas that could be enhanced. The audit was subdivided into three phases. Phase 1 was a preliminary assessment of current performance based on recent performance on CANSPEX samples. IGL performance was also compared to laboratories world-wide with similar scope. Phase 2 consisted of the implementation of the recommended changes made in Phase 1. Phase 3 of the audit consisted of a reassessment effort to evaluate the effectiveness of the recommendations made in the Phase 1 and an on-site audit of the laboratory facilities. Phases 1 and 3 required summary reports that are included in Appendices A and B of this report. The audit found that the IGL was one of the top two laboratories compared for trace element analyses. Several recommendations to enhance performance on major and minor elemental parameters were made and implemented. Demonstrated performance improvements as a result of the recommended changes were documented. Several initiatives to sustain the performance improvements gained from the audit have been implemented.

Le Conte's sparrows breeding in Conservation Reserve Program fields: precipitation and patterns of population change

USGS Publications Warehouse

Igl, Lawrence D.; Johnson, Douglas H.

1999-01-01

The climate of the North American Great Plains is highly dynamic, with great year-to-year variability in precipitation and periodic, often extreme, wet and dry cycles (Bragg 1995). Drought is a major force of ecological disturbance on the Great Plains and has played a key role in directing the evolution of the grassland biota of this region (Knopf and Samson 1997). Although grassland birds may differ in their responses to enviromenental variations (Rotenberry and Wiens 1991), climatic variability and concomitant unpredictability of resources strongly influence populations of grassland birds across space and time (Wiens 1974, 1986; Cody 1985). Not surprisingly, breeding bird populations on the Great Plains are highly dynamic, exhibiting considerable annual variation in composition, abundance, and distribution (Johnson and Grier 1988, George et al. 1992, Zimmerman 1992, Igl and Johnson 1997). Recently, interest in grassland birds has increased with the recognition that many species are declining both continentally (Droege and Sauer 1994) and globally (Goriup 1988). Identification of the specific factors associated with grassland bird declines in North America, however, remains largely enigmatic (Herkert 1997), and it is complicated by the considerable annual fluctuations in grassland bird distribution and abundance (Igl and Johnson 1997). Although there is evidence that land-use changes on the breeding grounds may have contributed to grassland bird declines (e.g., Igl and Johnson 1997), there also is an indication that long-term drought conditions may have influenced recent population changes of some breeding birds on the Great Plains (Droege and Sauer 1989, Peterjohn and Sauer 1993, Bethke and Nudds 1995, Igl and Johnson 1997). Le Conte's Sparrow (Ammodramus leconteii) is a secretive grassland bird that breeds in central and southern Canada and the northcentral United States (Murray 1969). It winters primarily in the southern United States (Peterson 1980, 1990). Like populations of many grassland breeding birds in North America (Fretwell 1986, Igl and Johnson 1997), Le Conte's Sparrow populations exhibit numerical highs and lows depending on local moisture conditions (Peabody 1901, Stewart 1975, Knapton 1979, Zimmer 1979, Madden 1996). This observation, however, is based largely on anecdotal evidence or short-term observations. Long-term studies of Le Conte's Sparrow populations are limited. Le Conte's Sparrow is poorly represented on the North American Breeding Bird Survey (BBS) because of small sample sizes, poor coverage in the northern portion of its breeding range, and the species' furtive behavior (Sauer et al. 1995). Moreover, dramatic fluctuations in Le Conte's Sparrow abundance tend to obscure the species' long-term population trends on the BBS (Sauer et al. 1995). In this paper we examine long-term population changes of Le Conte's Sparrows breeding in perennial grassland fields enrolled in the Conservation Reserve Program (CRP) on the northern Great Plains. We discuss patterns of population change of Le Conte's Sparrows associated with changes in precipitation and moisture conditions.

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

PubMed Central

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

2013-01-01

BACKGROUND Surgical reconstruction of a flail posterior leaflet is a routine mitral valve repair, the techniques for which have evolved from leaflet resection to leaflet preservation. Artificial ePTFE neochordae are frequently used to stabilize the flail leaflet, and seldom translocation of the native secondary chordae of the valve to the leaflet free edge is used. In this study, we sought to investigate the efficacy of the two techniques to correct posterior leaflet prolapse and reduce mitral regurgitation, and quantify the acute post-repair leaflet kinematics. METHODS Adult porcine mitral valves (N =7) were studied in a pulsatile left heart experimental model in which isolated P2 flail was mimicked by marginal chordal transection. Baseline conditions were established in each valve under normal conditions (control), and followed by induction of isolated P2 flail by transecting the two marginal chordae on the posterior leaflet free edge (disease). The flail posterior leaflet was reconstructed using artificial neochordae (repair 1) and then native chordal translocation (repair 2). Reduction in leaflet flail, changes in mitral regurgitation fraction, leaflet coaptation length, and posterior leaflet mobility were measured using B-mode echocardiography or color doppler. RESULTS At baseline, all the valves were competent with no mitral regurgitation. After transection of the marginal chordae on the posterior leaflet, isolated P2 flail was evident with 13.7±13% regurgitation. Reconstruction with artificial neochordae eliminated leaflet flail and reduced mitral regurgitation to 3.2± 2.8%, and with chordal translocation leaflet flail was corrected and mitral regurgitation was measured at 2.3±2.6%. Using either repair techniques, leaflet coaptation and mobility of the repaired leaflets were adequate and comparable to the baseline measurements. CONCLUSIONS Comparable reduction leaflet flail and regurgitation, and restoration of physiological leaflet coaptation with the two techniques indicates that under acute conditions, use of artificial neochordae or native chordal translocations have similar benefits. PMID:23291143

Doctors and pharmacists provision and opinions of medicines information leaflets in New Zealand.

PubMed

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.

Medicine information leaflets for non-steroidal anti-inflammatory drugs in Thailand.

PubMed

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.

Impact of Clinically Relevant Elliptical Deformations on the Damage Patterns of Sagging and Stretched Leaflets in a Bioprosthetic Heart Valve.

PubMed

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.

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

PubMed

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

2015-01-01

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

A new self-expandable aortic valved stent deployed above native leaflets for aortic insufficiency: an in vitro study.

PubMed

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.

Highly sensitive and unbiased approach for elucidating antibody repertoires

PubMed Central

Lin, Sherry G.; Ba, Zhaoqing; Du, Zhou; Zhang, Yu; Hu, Jiazhi; Alt, Frederick W.

2016-01-01

Developing B lymphocytes undergo V(D)J recombination to assemble germ-line V, D, and J gene segments into exons that encode the antigen-binding variable region of Ig heavy (H) and light (L) chains. IgH and IgL chains associate to form the B-cell receptor (BCR), which, upon antigen binding, activates B cells to secrete BCR as an antibody. Each of the huge number of clonally independent B cells expresses a unique set of IgH and IgL variable regions. The ability of V(D)J recombination to generate vast primary B-cell repertoires results from a combinatorial assortment of large numbers of different V, D, and J segments, coupled with diversification of the junctions between them to generate the complementary determining region 3 (CDR3) for antigen contact. Approaches to evaluate in depth the content of primary antibody repertoires and, ultimately, to study how they are further molded by secondary mutation and affinity maturation processes are of great importance to the B-cell development, vaccine, and antibody fields. We now describe an unbiased, sensitive, and readily accessible assay, referred to as high-throughput genome-wide translocation sequencing-adapted repertoire sequencing (HTGTS-Rep-seq), to quantify antibody repertoires. HTGTS-Rep-seq quantitatively identifies the vast majority of IgH and IgL V(D)J exons, including their unique CDR3 sequences, from progenitor and mature mouse B lineage cells via the use of specific J primers. HTGTS-Rep-seq also accurately quantifies DJH intermediates and V(D)J exons in either productive or nonproductive configurations. HTGTS-Rep-seq should be useful for studies of human samples, including clonal B-cell expansions, and also for following antibody affinity maturation processes. PMID:27354528

Cloning and characterization of indole synthase (INS) and a putative tryptophan synthase α-subunit (TSA) genes from Polygonum tinctorium.

PubMed

Jin, Zhehao; Kim, Jin-Hee; Park, Sang Un; Kim, Soo-Un

2016-12-01

Two cDNAs for indole-3-glycerol phosphate lyase homolog were cloned from Polygonum tinctorium. One encoded cytosolic indole synthase possibly in indigoid synthesis, whereas the other encoded a putative tryptophan synthase α-subunit. Indigo is an old natural blue dye produced by plants such as Polygonum tinctorium. Key step in plant indigoid biosynthesis is production of indole by indole-3-glycerol phosphate lyase (IGL). Two tryptophan synthase α-subunit (TSA) homologs, PtIGL-short and -long, were isolated by RACE PCR from P. tinctorium. The genome of the plant contained two genes coding for IGL. The short and the long forms, respectively, encoded 273 and 316 amino acid residue-long proteins. The short form complemented E. coli ΔtnaA ΔtrpA mutant on tryptophan-depleted agar plate signifying production of free indole, and thus was named indole synthase gene (PtINS). The long form, either intact or without the transit peptide sequence, did not complement the mutant and was tentatively named PtTSA. PtTSA was delivered into chloroplast as predicted by 42-residue-long targeting sequence, whereas PtINS was localized in cytosol. Genomic structure analysis suggested that a TSA duplicate acquired splicing sites during the course of evolution toward PtINS so that the targeting sequence-containing pre-mRNA segment was deleted as an intron. PtINS had about two to fivefolds higher transcript level than that of PtTSA, and treatment of 2,1,3-benzothiadiazole caused the relative transcript level of PtINS over PtTSA was significantly enhanced in the plant. The results indicate participation of PtINS in indigoid production.

Identification of genetic aberrations on chromosome 22 outside the NF2 locus in schwannomatosis and neurofibromatosis type 2.

PubMed

Buckley, Patrick G; Mantripragada, Kiran K; Díaz de Ståhl, Teresita; Piotrowski, Arkadiusz; Hansson, Caisa M; Kiss, Hajnalka; Vetrie, David; Ernberg, Ingemar T; Nordenskjöld, Magnus; Bolund, Lars; Sainio, Markku; Rouleau, Guy A; Niimura, Michihito; Wallace, Andrew J; Evans, D Gareth R; Grigelionis, Gintautas; Menzel, Uwe; Dumanski, Jan P

2005-12-01

Schwannomatosis is characterized by multiple peripheral and cranial nerve schwannomas that occur in the absence of bilateral 8th cranial nerve schwannomas. The latter is the main diagnostic criterion of neurofibromatosis type 2 (NF2), which is a related but distinct disorder. The genetic factors underlying the differences between schwannomatosis and NF2 are poorly understood, although available evidence implicates chromosome 22 as the primary location of the gene(s) of interest. To investigate this, we comprehensively profiled the DNA copy number in samples from sporadic and familial schwannomatosis, NF2, and a large cohort of normal controls. Using a tiling-path chromosome 22 genomic array, we identified two candidate regions of copy number variation, which were further characterized by a PCR-based array with higher resolution. The latter approach allows the detection of minute alterations in total genomic DNA, with as little as 1.5 kb per measurement point of nonredundant sequence on the array. In DNA derived from peripheral blood from a schwannomatosis patient and a sporadic schwannoma sample, we detected rearrangements of the immunoglobulin lambda (IGL) locus, which is unlikely to be due to a B-cell specific somatic recombination of IGL. Analysis of normal controls indicated that these IGL rearrangements were restricted to schwannomatosis/schwannoma samples. In the second candidate region spanning GSTT1 and CABIN1 genes, we observed a frequent copy number polymorphism at the GSTT1 locus. We further describe missense mutations in the CABIN1 gene that are specific to samples from schwannomatosis and NF2 and make this gene a plausible candidate for contributing to the pathogenesis of these disorders. Copyright 2005 Wiley-Liss, Inc.

The readability and suitability of sexual health promotion leaflets.

PubMed

Corcoran, Nova; Ahmad, Fatuma

2016-02-01

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

Mitral leaflet geometry perturbations with papillary muscle displacement and annular dilatation: an in-vitro study of ischemic mitral regurgitation.

PubMed

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.

Simulation of long-term fatigue damage in bioprosthetic heart valves: effects of leaflet and stent elastic properties

PubMed Central

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

Content analysis of nutritional information in paediatric oral health education leaflets.

PubMed

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.

Crutches, confetti or useful tools? Professionals' views on and use of health education leaflets.

PubMed

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.

Advertising, expectations and informed consent: the contents and functions of acupuncture leaflets.

PubMed

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.

Stent and leaflet stresses in a 26-mm first-generation balloon-expandable transcatheter aortic valve.

PubMed

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.

The halo of M 49 and its environment as traced by planetary nebulae populations

NASA Astrophysics Data System (ADS)

Hartke, J.; Arnaboldi, M.; Longobardi, A.; Gerhard, O.; Freeman, K. C.; Okamura, S.; Nakata, F.

2017-07-01

Context. The galaxy M 49 (NGC 4472) is the brightest early-type galaxy in the Virgo Cluster. It is located in subcluster B and has an unusually blue, metal-poor outer halo. Planetary nebulae (PNe) are excellent tracers of diffuse galaxy and intragroup light (IGL). Aims: We aim to present a photometric survey of PNe in the galaxy's extended halo to characterise its PN population, as well as the surrounding IGL of the subcluster B. Methods: PNe were identified based on their bright [OIII]5007 Å emission and absence of a broad-band continuum through automated detection techniques. Results: We identify 738 PNe out to a radius of 155 kpc from M 49's centre from which we define a complete sample of 624 PNe within a limiting magnitude of m5007,lim = 28.8. Comparing the PN number density to the broad-band stellar surface brightness profile, we find a variation of the PN-specific frequency (α-parameter) with radius. The outer halo beyond 60kpc has a 3.2 times higher α-parameter compared to the main galaxy halo (α2.5,innerM 49 = (3.20 ± 0.43) × 10-9 PN L-1⊙,bol), which is likely due to contribution from the surrounding blue IGL. We use the planetary nebulae luminosity function (PNLF) as an indicator of distance and stellar population. Its slope, which correlates empirically with galaxy type, varies within the inner halo. In the eastern quadrant of M 49, the PNLF slope is shallower, indicating an additional localised, bright PN population following an accretion event, likely that of the dwarf irregular galaxy VCC1249. We also determined a distance modulus of μPNLF = 31.29+ 0.07-0.08 for M 49, corresponding to a physical distance of 18.1 ± 0.6 Mpc, which agrees with a recent surface-brightness fluctuations distance. Conclusions: The PN populations in the outer halo of M 49 are consistent with the presence of a main Sérsic galaxy halo with a slight (B - V) colour gradient of 10-4 mag arcsec-1 surrounded by IGL with a very blue colour of (B - V) = 0.25 and a constant surface brightness μV = 28.0 mag arcsec-2. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan under programme S14A-006.

'What do patients want?' Tailoring medicines information to meet patients' needs.

PubMed

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.

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

PubMed Central

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

Adaptation of child oral health education leaflets for Arabic migrants in Australia: a qualitative study.

PubMed

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.

Simulated transcatheter aortic valve deformation: A parametric study on the impact of leaflet geometry on valve peak stress.

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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

2012-06-01

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

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

PubMed

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

2016-12-01

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

Congenital uni-leaflet mitral valve with severe stenosis: A case report with literature review.

PubMed

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.

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

PubMed Central

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

2015-01-01

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

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

DOE PAGES

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

2016-04-27

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

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

PubMed

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

2015-11-01

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

LMS Projects: A Platform for Intergenerational E-Learning Collaboration

ERIC Educational Resources Information Center

Lyashenko, Maria Sergeyevna; Frolova, Natalja Hidarovna

2014-01-01

Intergenerational learning (IGL) is the process of bringing seniors and juniors together in a collaborative space. Universities have been known to create a stimulating context for generations to share and acquire skills. The purpose of this paper is to present the results of research in the field of intergenerational learning and skills sharing.…

Lessons Learned: The McMaster Inquiry Story from Innovation to Institutionalization

ERIC Educational Resources Information Center

Cuneo, Carl; Harnish, Del; Roy, Dale; Vajoczki, Susan

2012-01-01

There are unique moments in curriculum development when an opportunity for a fresh start or a major turn in design fleetingly presents itself. These moments opened up in different locations across McMaster University at different times and eventually led to several quite different initiatives in inquiry-guided learning (IGL). Well-travelled…

Intergenerational Learning among Teachers: Overt and Covert Forms of Continuing Professional Development

ERIC Educational Resources Information Center

Brücknerová, Karla; Novotný, Petr

2017-01-01

This article interprets data from qualitative research into intergenerational learning (IGL) among teachers at Czech primary and secondary schools. The objective of the text is to answer the question: "What are teachers of different generations learning from one another in schools and in what ways does this learning take place?" Drawing…

Stress Analysis of Transcatheter Aortic Valve Leaflets Under Dynamic Loading: Effect of Reduced Tissue Thickness.

PubMed

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.

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…

Insulin lispro low mixture twice daily versus basal insulin glargine once daily and prandial insulin lispro once daily in patients with type 2 diabetes requiring insulin intensification: a randomized phase IV trial.

PubMed

Tinahones, F J; Gross, J L; Onaca, A; Cleall, S; Rodríguez, A

2014-10-01

To compare the efficacy and safety of two insulin intensification strategies in patients with type 2 diabetes inadequately controlled on basal insulin glargine with metformin and/or pioglitazone. A multinational, randomized, open-label trial that compared insulin lispro low mixture (LM25; n = 236) twice daily with a basal-prandial regimen of insulin glargine once daily and insulin lispro once daily (IGL; n = 240) over 24 weeks in patients with HbA1c 7.5-10.5% and fasting plasma glucose ≤ 6.7 mmol/l. The primary objective was to assess non-inferiority [per-protocol (PP) population], and then superiority [intention-to-treat (ITT) population], of LM25 versus IGL according to change in HbA1c after 24 weeks (non-inferiority margin 0.4%, two-sided significance level 0.05). Estimated change [least squares (LS) mean (95% CI)] in HbA1c after 24 weeks: -1.30 (-1.44, -1.16)% with LM25 and -1.08 (-1.22, -0.94)% with IGL. Non-inferiority was shown [LS mean (95% CI) HbA1c treatment difference -0.21 (-0.38, -0.04) (PP population)]; gated superiority assessment showed a statistically significant advantage for LM25 (p = 0.010; ITT population). Mean blood glucose, glycaemic variability, overall tolerability and hypoglycaemic episodes per patient-year did not show significant differences between treatments during the study. In patients with type 2 diabetes inadequately controlled on once-daily basal insulin glargine and metformin and/or pioglitazone, intensification with LM25 was superior to a basal-prandial approach in terms of reduction in HbA1c after 24 weeks and did not increase hypoglycaemia episodes. © 2014 The Authors. Diabetes, Obesity and Metabolism published by JohnWiley & Sons Ltd.

Promotion of family planning services in practice leaflets.

PubMed

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.

[Evaluation of a self-care leaflet].

PubMed

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".

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

Randomised trial of mitral valve repair with leaflet resection versus leaflet preservation on functional mitral stenosis (The CAMRA CardioLink-2 Trial).

PubMed

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.

Colposcopy information leaflets: what women want to know and when they want to receive this information.

PubMed

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.

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

Overcoming the knowledge-behavior gap: The effect of evidence-based HPV vaccination leaflets on understanding, intention, and actual vaccination decision.

PubMed

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.

A scanning electron microscopy study of the invasion of leaflets of a bloat-safe and a bloat-causing legume by rumen microorganisms.

PubMed

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.

[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)…

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.

Primary School Teachers' Views on Intergenerational Learning

ERIC Educational Resources Information Center

Polat, Soner; Kazak, Ender

2015-01-01

The purpose of this study is to determine the views of primary school teachers on intergenerational learning (IGL). The study group consists of eight primary schools in the central district of Düzce during the 2013-2014 academic year and 13 teachers who teach in these schools. Participants were selected among teachers working in Düzce's city…

Are Serious Video Games Something More than a Game? A Review on the Effectiveness of Serious Games to Facilitate Intergenerational Learning

ERIC Educational Resources Information Center

Ypsilanti, Antonia; Vivas, Ana B.; Räisänen, Teppo; Viitala, Matti; Ijäs, Tuula; Ropes, Donald

2014-01-01

Aging diversity in organizations creates potential challenges, particularly for knowledge management, skills update and skills obsolescence. Intergenerational learning (IGL) involves knowledge building, innovation and knowledge transfer between generations within an organization (Ropes 2011). Serious games refer to the use of computer games in…

Pregnancy-induced remodeling of heart valves.

PubMed

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.

The contents of dental implant patient information leaflets available within the UK.

PubMed

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.

The development and testing of a brief ('gist-based') supplementary colorectal cancer screening information leaflet.

PubMed

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.

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

PubMed

Pires, Carla; Vigário, Marina; Cavaco, Afonso

2015-01-01

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

Provision of tricuspid valve leaflets by septal papillary muscles in the right ventricle of human and other mammal hearts.

PubMed

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.

Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles

DOE PAGES

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

Patient assessment of medication information leaflets and validation of the Evaluative Linguistic Framework (ELF).

PubMed

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.

Optimal Elastomeric Scaffold Leaflet Shape for Pulmonary Heart Valve Leaflet Replacement

PubMed Central

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

2012-01-01

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

Meningioma of the superior leaflet of the velum interpositum: A case report

PubMed Central

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

Curved butterfly bileaflet prosthetic cardiac valve

DOEpatents

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.

Anaesthesia information--what patients want to know.

PubMed

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.

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

PubMed

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

2015-10-01

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

Further insights into normal aortic valve function: role of a compliant aortic root on leaflet opening and valve orifice area.

PubMed

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.

Transcatheter valve underexpansion limits leaflet durability: implications for valve-in-valve procedures

PubMed Central

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

Kangaroo versus porcine aortic valve tissue--valve geometry morphology, tensile strength and calcification potential.

PubMed

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.

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

PubMed

Clerehan, Rosemary; Hirsh, Di; Buchbinder, Rachelle

2009-01-01

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

Theory of Laser-Stimulated Surface Processes.

DTIC Science & Technology

1983-05-01

variables9 4 via the Fourier expansion of AW. The correlation function can be written in terms of specific collective properties of the phonons by...9 -Eg/g 2 T - 11 IgL Ik odK 6(Udk-\\) (2.338)13 dk 1 \\f2k/ d(zk Using the selection rule, Eq. (2.334), along with Eq. (2.323), this can be

The Effects of Online Interactive Games on High School Students' Achievement and Motivation in History Learning

ERIC Educational Resources Information Center

Lin, Kuan-Cheng; Wei, Yu Che; Hung, Jason C.

2012-01-01

Many studies demonstrate that Digital Game Based Learning (DGBL) can foster learning effect. The purpose of this study is to survey whether the online game in junior high school students can encourage learning effect in Taiwan's History. So, the research applied Interactive Game-based Learning System (IGLS) to junior high history teaching as an…

Combination cancer chemotherapy with one compound: pluripotent bradykinin antagonists.

PubMed

Stewart, John M; Gera, Lajos; Chan, Daniel C; York, Eunice J; Simkeviciene, Vitalija; Bunn, Paul A; Taraseviciene-Stewart, Laimute

2005-08-01

Lung and prostate cancers are major health problems worldwide. Treatments with standard chemotherapy agents are relatively ineffective. Combination chemotherapy gives better treatment than a single agent because the drugs can inhibit the cancer in different pathways, but new therapeutic agents are needed for the treatment of both tumor types. Bradykinin (BK) antagonists offer advantages of combination therapy in one compound. These promising multitargeted anti-cancer compounds selectively stimulate apoptosis in cancers and also inhibit both angiogenesis and matrix metalloprotease (MMP) action in treated lung and prostate tumors in nude mice. The highly potent, metabolism-resistant bradykinin antagonist peptide dimer, B-9870 [SUIM-(DArg-Arg-Pro-Hyp-Gly-Igl-Ser-DIgl-Oic-Arg)2] (SUIM=suberimidyl; Hyp=4-hydroxyproline; Igl=alpha-(2-indanyl)glycine; Oic=octahydroindole-2-carboxylic acid) and its non-peptide mimetic, BKM-570 [2,3,4,5,6-pentafluorocinnamoyl-(o-2,6-dichlorobenzyl)-L-tyrosine-N-(4-amino-2,2,6,6-tetramethylpiperidyl)amide] are superior to the widely used but toxic chemotherapeutic drugs cisplatin and taxotere. In certain combinations, they act synergistically with standard anti-cancer drugs. Due to its structure and biological activity, BKM-570 is an attractive lead compound for derivatization and evaluation for lung and prostate cancer drugs.

Rapid pannus formation after few months of obstructing aortic mechanical prosthesis.

PubMed

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.

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.

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

PubMed

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

2016-12-29

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

Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets

PubMed Central

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

2016-01-01

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

Tricuspid leaflet resection in an open beating heart for the creation of a canine tricuspid regurgitation model.

PubMed

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.

Subnanometer structure of an asymmetric model membrane: Interleaflet coupling influences domain properties

DOE PAGES

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

An assessment of nutritional information in oral health education leaflets.

PubMed

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.

Consent information leaflets – readable or unreadable?

PubMed Central

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

Characterizing the Collagen Fiber Orientation in Pericardial Leaflets Under Mechanical Loading Conditions

PubMed Central

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

Iatrogenic Aortic Valve Perforation after Ventricular Septal Defect Repair

PubMed Central

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

Development of Prescription Drug Information Leaflets: Impact of Cognitive Effort and Patient Involvement on Prescription Medication Information Processing.

PubMed

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.

Acute Mitral Valve Dysfunction Due to Escape of Prosthetic Mechanical Leaflet and Peripheral Leaftlet Embolization.

PubMed

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.

Readability Analysis of the Package Leaflets for Biological Medicines Available on the Internet Between 2007 and 2013: An Analytical Longitudinal Study

PubMed Central

2016-01-01

Background The package leaflet included in the packaging of all medicinal products plays an important role in the transmission of medicine-related information to patients. Therefore, in 2009, the European Commission published readability guidelines to try to ensure that the information contained in the package leaflet is understood by patients. Objective The main objective of this study was to calculate and compare the readability levels and length (number of words) of the package leaflets for biological medicines in 2007, 2010, and 2013. Methods The sample of this study included 36 biological medicine package leaflets that were downloaded from the European Medicines Agency website in three different years: 2007, 2010, and 2013. The readability of the selected package leaflets was obtained using the following readability formulas: SMOG grade, Flesch-Kincaid grade level, and Szigriszt’s perspicuity index. The length (number of words) of the package leaflets was also measured. Afterwards, the relationship between these quantitative variables (three readability indexes and length) and categorical (or qualitative) variables were analyzed. The categorical variables were the year when the package leaflet was downloaded, the package leaflet section, type of medicine, year of authorization of biological medicine, and marketing authorization holder. Results The readability values of all the package leaflets exceeded the sixth-grade reading level, which is the recommended value for health-related written materials. No statistically significant differences were found between the three years of study in the readability indexes, although differences were observed in the case of the length (P=.002), which increased over the study period. When the relationship between readability indexes and length and the other variables was analyzed, statistically significant differences were found between package leaflet sections (P<.001) and between the groups of medicine only with regard 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

Readability Analysis of the Package Leaflets for Biological Medicines Available on the Internet Between 2007 and 2013: An Analytical Longitudinal Study.

PubMed

Piñero-López, María Ángeles; Modamio, Pilar; Lastra, Cecilia F; Mariño, Eduardo L

2016-05-25

The package leaflet included in the packaging of all medicinal products plays an important role in the transmission of medicine-related information to patients. Therefore, in 2009, the European Commission published readability guidelines to try to ensure that the information contained in the package leaflet is understood by patients. The main objective of this study was to calculate and compare the readability levels and length (number of words) of the package leaflets for biological medicines in 2007, 2010, and 2013. The sample of this study included 36 biological medicine package leaflets that were downloaded from the European Medicines Agency website in three different years: 2007, 2010, and 2013. The readability of the selected package leaflets was obtained using the following readability formulas: SMOG grade, Flesch-Kincaid grade level, and Szigriszt's perspicuity index. The length (number of words) of the package leaflets was also measured. Afterwards, the relationship between these quantitative variables (three readability indexes and length) and categorical (or qualitative) variables were analyzed. The categorical variables were the year when the package leaflet was downloaded, the package leaflet section, type of medicine, year of authorization of biological medicine, and marketing authorization holder. The readability values of all the package leaflets exceeded the sixth-grade reading level, which is the recommended value for health-related written materials. No statistically significant differences were found between the three years of study in the readability indexes, although differences were observed in the case of the length (P=.002), which increased over the study period. When the relationship between readability indexes and length and the other variables was analyzed, statistically significant differences were found between package leaflet sections (P<.001) and between the groups of medicine only with regard to the length over the three studied 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.

Melanocyte pigmentation stiffens murine cardiac tricuspid valve leaflet

PubMed Central

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

Phototropic leaf movements and photosynthetic performance in an amphibious fern, Marsilea quadrifolia.

PubMed

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.

Late leaflet fracture and embolization of a Duromedics mitral prosthesis.

PubMed

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.

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

PubMed

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

2014-08-01

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

Evaluation of written prescription information provided in community pharmacies: a study in eight states.

PubMed

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.

Prosthetic Mitral Valve Leaflet Escape

PubMed Central

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

Aberrant tendinous chords with tethering of the tricuspid leaflets: a congenital anomaly causing severe tricuspid regurgitation.

PubMed

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.

Promoting chlamydia screening with posters and leaflets in general practice--a qualitative study.

PubMed

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.

Promoting chlamydia screening with posters and leaflets in general practice - a qualitative study

PubMed Central

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

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

PubMed

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

2016-12-01

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

PN FOR CHILDREN - INFORMATION LEAFLET.

PubMed

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/

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

PubMed

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

2006-12-01

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

[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:…

Diffusion in phospholipid bilayer membranes: dual-leaflet dynamics and the roles of tracer–leaflet and inter-leaflet coupling

PubMed Central

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

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

PubMed Central

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

[TECHNIQUES IN MITRAL VALVE REPAIR VIA A MINIMALLY INVASIVE APPROACH].

PubMed

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.

Related Mechanisms of Antibody Somatic Hypermutation and Class Switch Recombination

PubMed Central

HWANG, JOYCE K.; ALT, FREDERICK W.; YEAP, LENG-SIEW

2015-01-01

The primary antibody repertoire is generated by mechanisms involving the assembly of the exons that encode the antigen-binding variable regions of immunoglobulin heavy (IgH) and light (IgL) chains during the early development of B lymphocytes. After antigen-dependent activation, mature B lymphocytes can further alter their IgH and IgL variable region exons by the process of somatic hypermutation (SHM), which allows the selection of B cells in which SHMs resulted in the production of antibodies with increased antigen affinity. In addition, during antigen-dependent activation, B cells can also change the constant region of their IgH chain through a DNA double-strand-break (DSB) dependent process referred to as IgH class switch recombination (CSR), which generates B cell progeny that produce antibodies with different IgH constant region effector functions that are best suited for a elimination of a particular pathogen or in a particular setting. Both the mutations that underlie SHM and the DSBs that underlie CSR are initiated in target genes by activation-induced cytidine deaminase (AID). This review describes in depth the processes of SHM and CSR with a focus on mechanisms that direct AID cytidine deamination in activated B cells and mechanisms that promote the differential outcomes of such cytidine deamination. PMID:26104555

Pannus overgrowth after mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis.

PubMed

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.

Maximally asymmetric transbilayer distribution of anionic lipids alters the structure and interaction with lipids of an amyloidogenic protein dimer bound to the membrane surface

PubMed Central

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

Key facts. Leaflets.

PubMed

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.

Partial hammock valve: surgical repair in adulthood.

PubMed

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.

Aberrant tendinous chords with tethering of the tricuspid leaflets: a congenital anomaly causing severe tricuspid regurgitation

PubMed Central

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

Bilayer registry in a multicomponent asymmetric membrane: Dependence on lipid composition and chain length

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

Efficiency of printed materials in worksite health promotion.

PubMed

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.

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…

E-learning or educational leaflet: does it make a difference in oral health promotion? A clustered randomized trial.

PubMed

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.

Restoration of Tricuspid Valve Mechanism at the Level of Displaced Septal and Posterior Leaflets in Ebstein's Anomaly.

PubMed

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.

Practitioner and lay perspectives of the service provision of nutrition information leaflets in primary care.

PubMed

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.

The usefulness and scientific accuracy of private sector Arabic language patient drug information leaflets.

PubMed

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.

Occluder closing behavior: a key factor in mechanical heart valve cavitation.

PubMed

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.

A novel arthroscopic all-inside suture technique using the Fast-Fix 360 system for repairing horizontal meniscal tears in young athletes

PubMed Central

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

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.

Creation New Patient Information Leaflets with Diabetes by Pharmacists and Assesment Conducted by Patients.

PubMed

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.

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

PubMed Central

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

2016-01-01

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

Automated segmentation and geometrical modeling of the tricuspid aortic valve in 3D echocardiographic images.

PubMed

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.

Retrieval of a leaflet escaped in a Tri-technologies bileaflet mechanical prosthetic valve.

PubMed

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.

Structural basis for maintenance of bacterial outer membrane lipid asymmetry.

PubMed

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.

Evaluating the application of research-based guidance to the design of an emergency preparedness leaflet.

PubMed

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.

Isolated effect of geometry on mitral valve function for in silico model development.

PubMed

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.

Blistering of langmuir-blodgett bilayers containing anionic phospholipids as observed by atomic force microscopy.

PubMed Central

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

Systolic Anterior Motion of the Mitral Valve after Mitral Valve Repair

PubMed Central

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

Outlet strut fracture and leaflet escape of Bjork-Shiley convexo-concave valve.

PubMed

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.

Maximally asymmetric transbilayer distribution of anionic lipids alters the structure and interaction with lipids of an amyloidogenic protein dimer bound to the membrane surface.

PubMed

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.

Computational fluid dynamics simulation of transcatheter aortic valve degeneration.

PubMed

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.

Three patients with signs of acute flail mitral leaflet seen on emergency department echo: a critical constellation within the focused cardiac exam

PubMed Central

Stephenson, George; Wallace, Craig; Mao, Pras; Moore, Chris

2015-01-01

Abstract Acute flail mitral leaflet is a time‐sensitive, reversible cause of cardiogenic shock. Transthoracic echocardiography (echo) is increasingly becoming a vital tool for non‐cardiologist physicians who treat patients with undifferentiated chest pain and dyspnoea. The sonographic abnormalities seen in acute flail mitral leaflet are within the boundaries of a focused echo. Individually, these findings are non‐specific. As a constellation, however, they are highly suggestive of this disease process. We present a case series of three patients with acute flail mitral leaflet seen on emergency department echo along with a discussion of the findings and the disease itself. PMID:28191212

Double, Double Toil and Trouble: The Melt Inclusion Bubble

NASA Astrophysics Data System (ADS)

Rasmussen, D. J.; Plank, T. A.

2017-12-01

Melt inclusions provide a powerful means for probing the depth of magmatic processes and volatile budgets of magmas. Both objectives require that the inclusions accurately record the volatile content of the entrapped melt. However, post-entrapment cooling and diffusive loss of water lead to a decrease in internal pressure, resulting in volatile exsolution (importantly CO2) and vapor bubble growth in inclusions. Several methods have been developed recently that attempt to reconstruct the entrapped CO2 contents, but the methods yield inconsistent results. Here we report on new homogenization experiments and attempt to reconcile inconsistencies in CO2 reconstruction methods. Experiments were conducted on olivine-hosted melt inclusions from Seguam volcano using a piston cylinder apparatus at 500 MPa, 1150-1170 °C, hydrous conditions, and a run duration of 1-2 hours. FTIR analyses of the homogenized inclusions show some diffusive water gain (≤1 wt% excess) relative to unheated inclusions (most 4 wt%). Inclusions from this same sample were previously reconstructed using Raman addition (RA; Moore et al., 2015), and we have constituted the CO2 with two different computational approaches: the ideal gas law (IGL; Shaw et al., 2010) and a bubble growth model (BG; Riker, 2005). CO2 and S contents of heated inclusions are correlated, defining a S-CO2 degassing path. Relative to this empirical degassing path, IGL results are offset to higher CO2 (100s-1000s of ppm) or lower S (100s of ppm), while RA and BG results overlap and are offset to lower CO2 (≤100s of ppm) or higher S (≤100s of ppm). Because S contents of heated and unheated inclusions have similar ranges, we attribute the discrepancy to CO2. High values of CO2 from the IGL correction may be because CO2 diffusion cannot keep pace with bubble growth during rapid cooling upon eruption. Mass balance calculations indicate that a minute amount of carbonate, which could escape detection by Raman, would affect CO2 content, providing an explanation for low values of CO2 determined by RA. The discrepancy in the BG results might relate to diffusive loss of H+ and uncertainties (e.g., temperature) involved with the calculation. Thus, homogenization via heating has advantages over other techniques in constituting the CO2 of inclusions, and may lead to a more accurate computational method.

Intrauterine Growth Restriction Affects Cerebellar Granule Cells in the Developing Guinea Pig Brain.

PubMed

Tolcos, Mary; McDougall, Annie; Shields, Amy; Chung, Yoonyoung; O'Dowd, Rachael; Turnley, Ann; Wallace, Megan; Rees, Sandra

2018-01-01

Intrauterine growth restriction (IUGR) can lead to adverse neurodevelopmental sequelae in postnatal life. However, the effects of IUGR on the cerebellum are still to be fully elucidated. A major determinant of growth and development of the cerebellum is proliferation and subsequent migration of cerebellar granule cells. Our objective was to determine whether IUGR, induced by chronic placental insufficiency (CPI) in guinea pigs, results in abnormal cerebellar development due to deficits suggestive of impaired granule cell proliferation and/or migration. CPI was induced by unilateral ligation of the uterine artery at mid-gestation, producing growth-restricted (GR) foetuses at 52 and 60 days of gestation (dg), and neonates at 1 week postnatal age (term approx. 67 dg). Controls were from sham-operated animals. In GR foetuses compared with controls at 52 dg, the external granular layer (EGL) width and internal granular layer (IGL) area were similar. In GR foetuses compared with controls at 60 dg: (a) the EGL width was greater (p < 0.005); (b) the IGL area was smaller (p < 0.005); (c) the density of Ki67-negative (postmitotic) granule cells in the EGL was greater (p < 0.01); (d) the somal area of Purkinje cells was reduced (p < 0.005), and (e) the linear density of Bergmann glia was similar. The EGL width in GR foetuses at 60 dg was comparable to that of 52 dg control and GR foetuses. The pattern of p27-immunoreactivity in the EGL was the inverse of Ki67-immunoreactivity at both foetal ages; there was no difference between control and GR foetuses at either age in the width of p27-immunoreactivity, or in the percentage of the EGL width that it occupied. In the molecular layer of GR neonates compared with controls there was an increase in the areal density of granule cells (p < 0.05) and in the percentage of migrating to total number of granule cells (p < 0.01) at 1 week but not at 60 dg (p > 0.05). Thus, we found no specific evidence that IUGR affects granule cell proliferation, but it alters the normal program of migration to the IGL and, in addition, the development of Purkinje cells. Such alterations will likely affect the development of appropriate circuitry and have implications for cerebellar function. © 2018 S. Karger AG, Basel.

Mechanism of valvular regurgitation.

PubMed

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.

Flail anterior tricuspid valve leaflet in a neonate: association with maternal antiphospholipid syndrome.

PubMed

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.

Effect of a leaflet given to parents on knowledge of tooth avulsion.

PubMed

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.

Comparison of transcatheter aortic valve and surgical bioprosthetic valve durability: a fatigue simulation study

PubMed Central

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

Opening and closing characteristics of the aortic valve after valve-sparing procedures using a new aortic root conduit.

PubMed

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.

Determination of the structures of small gold clusters on stepped magnesia by density functional calculations.

PubMed

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

Morphologic-echocardiographic correlates of Ebstein's malformation.

PubMed

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.

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

PubMed

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.

INTERLAYER MICROMECHANICS OF THE AORTIC HEART VALVE LEAFLET

PubMed Central

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

Neoseiulus californicus (Acari: Phytoseiidae) as a potential control agent of Tetranychus urticae (Acari: Tetranychidae): effect of pest/predator ratio on pest abundance on strawberry.

PubMed

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.

Manipulation of valve composition to elucidate the role of collagen in aortic valve calcification

PubMed Central

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

Comprehensive 4-stage categorization of bicuspid aortic valve leaflet morphology by cardiac MRI in 386 patients.

PubMed

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.

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

PubMed

Takeuchi, Shoko; Horiuchi, Shigeko

2016-10-01

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

Isolated Effect of Geometry on Mitral Valve Function for In-Silico Model Development

PubMed Central

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

Fluid-structure interaction study of transcatheter aortic valve dynamics using smoothed particle hydrodynamics

PubMed Central

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

Fluid-Structure Interaction Study of Transcatheter Aortic Valve Dynamics Using Smoothed Particle Hydrodynamics.

PubMed

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.

Light-dependent changes in the leaflet movement rhythm of the plant Desmodium gyrans.

PubMed

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.

Prediction of oxygen distribution in aortic valve leaflet considering diffusion and convection.

PubMed

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.

Measurement and reconstruction of the leaflet geometry for a pericardial artificial heart valve.

PubMed

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.

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

PubMed

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

2010-12-01

Hundreds of thousands of volunteers take part in medical research, but many will never hear from researchers about what the study revealed. There is a growing demand for the results of randomised trials to be fed back to research participants both for ethical research practice and for ensuring their co-operation in a trial. This study aims to determine participants' preferences for type of leaflet (short versus long) used to summarise the findings of a randomised trial; and to test whether certain characteristics explained participants' preferences. 553 participants in a randomised trial about General Practitioners' access to Magnetic Resonance Imaging for patients presenting with suspected internal derangement of the knee were asked in the final follow-up questionnaire whether they would like to be fed back the results of the trial. Participants who agreed to this were included in a postal questionnaire survey asking about their preference, if any, between a short and a long leaflet and what it was about the leaflet that they preferred. Multinomial logistic regression was used to test whether certain demographics of responding participants along with treatment group explained whether a participant had a preference for type of leaflet or no preference. Of the participants who returned the final follow-up questionnaire, 416 (88%) agreed to receive the results of the trial. Subsequently 132 (32%) participants responded to the survey. Most participants preferred the longer leaflet (55%) and the main reasons for this were the use of technical information (94%) and diagrams (89%). There was weak evidence to suggest that gender might explain whether participants have a preference for type of leaflet or not (P = 0.084). Trial participants want to receive feed back about the results and appear to prefer a longer leaflet. Males and females might require information to be communicated to them differently and should be the focus of further research. The trial is registered with http://www.isrctn.org/ and ID is ISRCTN76616358.

Distribution of vesicular glutamate transporter 1 (VGLUT1) in the mouse esophagus.

PubMed

Kraus, T; Neuhuber, W L; Raab, M

2007-08-01

In rat and mouse esophagus, vesicular glutamate transporter 2 (VGLUT2) has been demonstrated to identify vagal intraganglionic laminar endings (IGLEs); this has recently also been shown for VGLUT1 in rat esophagus. In this study, we have investigated the distribution of VGLUT1 in the mouse esophagus and compared these results with the recently published data from the rat esophagus. Unexpectedly, we have discovered that VGLUT1 mostly fails to identify IGLEs in the mouse esophagus. This is surprising, since the distribution of VGLUT2 shows comparable results in both species. Confocal imaging has revealed substantial colocalization of VGLUT1 immunoreactivity (-ir) with cholinergic and nitrergic/peptidergic markers within the myenteric neuropil and in both cholinergic and nitrergic myenteric neuronal cell bodies. VGLUT1 and cholinergic markers have also been colocalized in fibers of the muscularis mucosae, whereas VGLUT1 and nitrergic markers have never been colocalized in fibers of the muscularis mucosae, although this does occur in fibers of the muscularis running to motor endplates. Thus, VGLUT1 is contained in the nitrergic innervation of mouse esophageal motor endplates, another difference from the rat esophagus. VGLUT1-ir is therefore present in extrinsic and intrinsic innervation of the mouse esophagus, but the significant differences from the rat indicate species variations concerning the distribution of VGLUTs in the peripheral nervous system.

Planar biaxial testing of heart valve cusp replacement biomaterials: Experiments, theory and material constants.

PubMed

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.

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

PubMed

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

2009-04-01

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

Model of an asymmetric DPPC/DPPS membrane: effect of asymmetry on the lipid properties. A molecular dynamics simulation study.

PubMed

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.

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

PubMed Central

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

2013-01-01

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

Evolving Techniques for Mitral Valve Reconstruction

PubMed Central

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

Biomechanical and ultrastructural comparison of cryopreservation and a novel cellular extraction of porcine aortic valve leaflets.

PubMed

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.

Microstructured Nickel-Titanium Thin Film Leaflets for Hybrid Tissue Engineered Heart Valves Fabricated by Magnetron Sputter Deposition.

PubMed

Loger, K; Engel, A; Haupt, J; Lima de Miranda, R; Lutter, G; Quandt, E

2016-03-01

Heart valves are constantly exposed to high dynamic loading and are prone to degeneration. Therefore, it is a challenge to develop a durable heart valve substitute. A promising approach in heart valve engineering is the development of hybrid scaffolds which are composed of a mechanically strong inorganic mesh enclosed by valvular tissue. In order to engineer an efficient, durable and very thin heart valve for transcatheter implantations, we developed a fabrication process for microstructured heart valve leaflets made from a nickel-titanium (NiTi) thin film shape memory alloy. To examine the capability of microstructured NiTi thin film as a matrix scaffold for tissue engineered hybrid heart valves, leaflets were successfully seeded with smooth muscle cells (SMCs). In vitro pulsatile hydrodynamic testing of the NiTi thin film valve leaflets demonstrated that the SMC layer significantly improved the diastolic sufficiency of the microstructured leaflets, without affecting the systolic efficiency. Compared to an established porcine reference valve model, magnetron sputtered NiTi thin film material demonstrated its suitability for hybrid tissue engineered heart valves.

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.

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

PubMed Central

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

2016-01-01

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

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

PubMed

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

2016-12-06

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

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

Design and ergonomics of package inserts of drugs in Brazil: a reality in construction.

PubMed

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.

Final Remedial Investigation Sampling Plan Addendum. Milan Army Ammunition Plant Remedial Investigation Southern Study Area (Operable Unit No. 5)

DTIC Science & Technology

1997-09-01

91-D-0012 Task Order No. 0007 2.4.7 Milan Army Ammunition Plant, Phytoremediation Pilot Study, USAEC, 1996 .. .............................. 2-28 2.5...indicated that heavy metal contamination (lead, chromium, and mercury ) was present at relatively low levels, and explosive contamination was limited to...and MI172 where lead was found at 22.9 j.g/1 and 18.4 Ig/l, respectively. 2.4.7 Milan Army Ammunition Plant, Phytoremediation Pilot Study, USAEC, 1996

Quantification and comparison of the mechanical properties of four human cardiac valves.

PubMed

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.

3D echocardiographic location of implantable device leads and mechanism of associated tricuspid regurgitation.

PubMed

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.

Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation.

PubMed

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.

Juvenile Rhus glabra leaves have higher temperatures and lower gas exchange rates than mature leaves when compared in the field during periods of high irradiance.

PubMed

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.

Leaflet escape in a new bileaflet mechanical valve: TRI technologies.

PubMed

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.

Robotic Posterior Mitral Leaflet Repair: Neochordal versus Resectional Techniques

PubMed Central

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

Assessment of the quality of medication information for patients in Spain.

PubMed

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.

Absence of posterior tricuspid valve leaflet and valve reconstruction

PubMed Central

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

Multi-physics 3D computational study of leaflet thrombus formation following surgical and transcatheter aortic valve replacement

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.

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

Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review.

PubMed

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.

Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review

PubMed Central

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

Mitral valve repair using ePTFE sutures for ruptured mitral chordae tendineae: a computational simulation study.

PubMed

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.

Cross sectional echocardiographic feature in carcinoid heart disease. A mechanism for tricuspid regurgitation in this syndrome.

PubMed

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.

Catheter Entrapment During Posterior Mitral Leaflet Pushing Maneuver for MitraClip Implantation.

PubMed

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.

Impact of Implantable Transvenous Device Lead Location on Severity of Tricuspid Regurgitation

PubMed Central

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

Crimping and deployment of balloon-expandable valved stents are responsible for the increase in the hydraulic conductance of leaflets.

PubMed

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.

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

PubMed Central

Ratcliffe, Mark B.; Guccione, Julius M.

2012-01-01

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

Severe mitral regurgitation due to mitral leaflet aneurysm diagnosed by three-dimensional transesophageal echocardiography: a case report.

PubMed

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.

Mitral valve coaptation and its relationship to late diastolic flow: A color Doppler and vector flow map echocardiographic study in normal subjects.

PubMed

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.

An inverse modeling approach for semilunar heart valve leaflet mechanics: exploitation of tissue structure.

PubMed

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.

Transapical endovascular implantation of neochordae using a suction and suture device.

PubMed

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.

Physiotherapy Post Lumbar Discectomy: Prospective Feasibility and Pilot Randomised Controlled Trial

PubMed Central

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

The inner side of T cell lipid rafts.

PubMed

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.

Mitral valve stenosis caused by abnormal pannus extension over the prosthetic ring and leaflets after Duran ring mitral annuloplasty.

PubMed

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.

Premeasured Chordal Loops for Mitral Valve Repair.

PubMed

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.

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.

A descriptive study of the readability of patient information leaflets designed by nurses.

PubMed

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.

How to improve the readability of the patient package leaflet: a survey on the use of colour, print size and layout.

PubMed

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.

Control of dissected leaf morphology by a Cys(2)His(2) zinc finger transcription factor in the model legume Medicago truncatula

PubMed Central

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

Mitral Valve Repair Using ePTFE Sutures for Ruptured Mitral Chordae Tendineae: A Computational Simulation Study

PubMed Central

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

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...

Hypoplasia or Absence of Posterior Leaflet: A Rare Congenital Anomaly of The Mitral Valve in Adulthood - Case Series.

PubMed

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.

The complex leaves of the monkey's comb (Amphilophium crucigerum, Bignoniaceae): a climbing strategy without glue.

PubMed

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.

Reproducibility of a novel echocardiographic 3D automated software for the assessment of mitral valve anatomy.

PubMed

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.

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

PubMed

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

2014-12-01

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

Readability of medicinal package leaflets: a systematic review.

PubMed

Pires, Carla; Vigário, Marina; Cavaco, Afonso

2015-01-01

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

Fluid-Structure Interaction and Structural Analyses using a Comprehensive Mitral Valve Model with 3D Chordal Structure

PubMed Central

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

Fluid-structure interaction and structural analyses using a comprehensive mitral valve model with 3D chordal structure.

PubMed

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.

Annular dilatation and loss of sino-tubular junction in aneurysmatic aorta: implications on leaflet quality at the time of surgery. A finite element study†

PubMed Central

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

Epicardially-derived Fibroblasts Preferentially Contribute to the Parietal Leaflets of the Atrioventricular Valves in the Murine Heart

PubMed Central

Wessels, Andy; van den Hoff, Maurice J. B.; Adamo, Richard F.; Phelps, Aimee L.; Lockhart, Marie M.; Sauls, Kimberly; Briggs, Laura E.; Norris, Russell A.; van Wijk, Bram; Perez-Pomares, Jose M.; Dettman, Robert W.; Burch, John B. E.

2012-01-01

The importance of the epicardium for myocardial and valvuloseptal development has been well established; perturbation of epicardial development results in cardiac abnormalities, including thinning of the ventricular myocardial wall and malformations of the atrioventricular valvuloseptal complex. To determine the spatiotemporal contribution of epicardially derived cells to the developing fibroblast population in the heart we have used a mWt1/IRES/GFP-Cre mouse to trace the fate of EPDCs from embryonic day (ED)10 until birth. EPDCs begin to populate the compact ventricular myocardium around ED12. The migration of epicardially-derived fibroblasts toward the interface between compact and trabecular myocardium is completed around ED14. Remarkably, epicardially-derived fibroblasts do not migrate into the trabecular myocardium until after ED17. Migration of EPDCs into the atrioventricular cushion mesenchyme commences around ED12. As development progresses, the number of EPDCs increases significantly, specifically in the leaflets which derive from the lateral atrioventricular cushions. In these developing leaflets the epicardially-derived fibroblasts eventually largely replace the endocardially-derived cells. Importantly, the contribution of EPDCs to the leaflets derived from the major AV cushions is very limited. The differential contribution of EPDCs to the various leaflets of the atrioventricular valves provides a new paradigm in valve development and could lead to new insights into the pathogenesis of abnormalities that preferentially affect individual components of this region of the heart. The notion that there is a significant difference in the contribution of epicardially and endocardially derived cells to the individual leaflets of the atrioventricular valves has also important pragmatic consequences for the use of endocardial and epicardial cre-mouse models in studies of heart development. PMID:22546693

Posterior leaflet preservation during mitral valve replacement for rheumatic mitral stenosis.

PubMed

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.

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.

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.

[A philosophical information leaflet to accompany a DSM classification].

PubMed

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.

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.

Correlation of two-dimensional echocardiography and pathologic findings in porcine valve dysfunction.

PubMed

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.

Treatment of severe mitral regurgitation caused by lesions in both leaflets using multiple mitral valve plasty techniques in a small dog

PubMed Central

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

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

NASA Astrophysics Data System (ADS)

Masoumi, Nafiseh

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

Surgical repair of tricuspid valve leaflet tear following percutaneous closure of perimembranous ventricular septal defect using Amplatzer duct occluder I: Report of two cases

PubMed Central

Kuwelker, Saatchi Mahesh; Shetty, Devi Prasad; Dalvi, Bharat

2017-01-01

Tricuspid valve (TV) injury following transcatheter closure of perimembranous ventricular septal defect (PMVSD) with Amplatzer ductal occluder I (ADO I), requiring surgical repair, is rare. We report two cases of TV tear involving the anterior and septal leaflets following PMVSD closure using ADO I. In both the patients, the subvalvular apparatus remained unaffected. The patients presented with severe tricuspid regurgitation (TR) 6 weeks and 3 months following the device closure. They underwent surgical repair with patch augmentation of the TV leaflets. Postoperatively, both are asymptomatic with a mild residual TR. PMID:28163430

Mapping of four distinct BCR-related loci to chromosome region 22q11: order of BCR loci relative to chronic myelogenous leukemia and acute lymphoblastic leukemia breakpoints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croce, C.M.; Huebner, K.; Isobe, M.

1987-10-01

A probe derived from the 3' region of the BCR gene (breakpoint cluster region gene) detects four distinct loci in the human genome. One of the loci corresponds to the complete BCR gene, whereas the other contain a 3' segment of the gene. After HindIII cleavage of human DNA, these four loci are detected as 23-, 19-, 13-, and 9-kikobase-pair fragments, designated BCR4, BCR3, BCR2, and BCR1, respectively, with BCR1 deriving from the original complete BCR gene. All four BCR loci segregate 100% concordantly with human chromosome 22 in a rodent-human somatic cell hybrid panel and are located at chromosomemore » region 22q11.2 by chromosomal in situ hybridization. The BCR2 and BCR4 loci are amplified in leukemia cell line K562 cells, indicating that they fall within the amplification unit that includes immunoglobulin lambda light chain locus (IGL) and ABL locus on the K562 Philadelphia chromosome (Ph/sup 1/). Similarly, in mouse-human hybrids retaining a Ph/sup 1/ chromosome derived from an acute lymphoblastic leukemia-in the absence of the 9q/sup +/ and 22, only BCR2 and BCR4 loci are retained. Thus, the order of loci on chromosome 22 is centromere ..-->.. BCR2, BCR4, and IGL ..-->.. BCR1 ..-->.. BCR3 ..-->.. SIS, possibly eliminating BCR2 and BCR4 loci as candidate targets for juxtaposition to the ABL gene in the acute lymphoblastic leukemia Ph/sup 1/ chromosome.« less

Hypoplasia or Absence of Posterior Leaflet: A Rare Congenital Anomaly of The Mitral Valve in Adulthood – Case Series

PubMed Central

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

Characterization of three-dimensional anisotropic heart valve tissue mechanical properties using inverse finite element analysis.

PubMed

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.

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…

[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…

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,"…

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

ERIC Educational Resources Information Center

Gal, Iddo; Prigat, Ayelet

2005-01-01

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

Transmembrane protein diffusion in gel-supported dual-leaflet membranes.

PubMed

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.

Enhancement of Phloem Exudation from Fraxinus uhdei Wenz. (Evergreen Ash) using Ethylenediaminetetraacetic Acid 1

PubMed Central

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

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

Impact of written information on control and adherence in type 2 diabetes.

PubMed

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.

Architecture of an in vivo-tissue engineered autologous conduit "Biovalve".

PubMed

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.

Echocardiographic assessment of mitral valve morphology and performance after triangular resection of the prolapsing posterior leaflet for degenerative myxomatous disease.

PubMed

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.

Mitral stenosis and hypertrophic obstructive cardiomyopathy: An unusual combination.

PubMed

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.

Tricuspid valve repair for severe tricuspid regurgitation due to pacemaker leads.

PubMed

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.

The clover technique for the treatment of complex tricuspid valve insufficiency: midterm clinical and echocardiographic results in 66 patients.

PubMed

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.

Virtual reality 3D echocardiography in the assessment of tricuspid valve function after surgical closure of ventricular septal defect.

PubMed

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.

Functional mitral stenosis after surgical annuloplasty for ischemic mitral regurgitation: Importance of subvalvular tethering in the mechanism and dynamic deterioration during exertion

PubMed Central

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

Quantity and location of aortic valve complex calcification predicts severity and location of paravalvular regurgitation and frequency of post-dilation after balloon-expandable transcatheter aortic valve replacement.

PubMed

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.

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

PubMed

Hirano, S S; Upper, C D

1989-03-01

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

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…

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…

Obstructed bi-leaflet prosthetic mitral valve imaging with real-time three-dimensional transesophageal echocardiography.

PubMed

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.

Spatiotemporal expression of MANF in the developing rat brain.

PubMed

Wang, Haiping; Ke, Zunji; Alimov, Alexander; Xu, Mei; Frank, Jacqueline A; Fang, Shengyun; Luo, Jia

2014-01-01

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an evolutionarily conserved neurotrophic factor which exhibited neuroprotective properties. Recent studies suggested that MANF may play a role in the neural development of Drosophila and zebra fishes. In this study, we investigated the spatiotemporal expression of MANF in the brain of postnatal and adult rats. MANF expression appeared wide spread and mainly localized in neurons. In the cerebral cortex, neurons in layer IV and VI displayed particularly strong MANF immunoreactivity. In the hippocampus, intensive MANF expression was observed throughout the subfields of Cornu Amonis (CA1, CA2, and CA3) and the granular layer of the dentate gyrus (DG). In the substantia nigra, high MANF expression was shown in the substantia nigra pars compacta (SNpc). In the thalamus, the anterodorsal thalamic nucleus (ADTN) exhibited the highest MANF immunoreactivity. In the hypothalamus, intensive MANF immunoreactivity was shown in the supraoptic nucleus (SON) and tuberomammillary nucleus (TMN). In the cerebellum, MANF was localized in the external germinal layer (EGL), Purkinje cell layer (PCL), internal granule layer (IGL) and the deep cerebellar nuclei (DCN). We examined the developmental expression of MANF on postnatal day (PD) 3, 5, 7, 9, 15, 21, 30 and adulthood. In general, the levels of MANF were high in the early PDs (PD3 and PD5), and declined gradually as the brain matured; MANF expression in the adult brain was the lowest among all time points examined. However, in some structures, such as PCL, IGL, SON, TMN and locus coeruleus (LC), high expression of MANF sustained throughout the postnatal period and persisted into adulthood. Our results indicated that MANF was developmentally regulated and may play a role in the maturation of the central nervous system (CNS).

Spatiotemporal Expression of MANF in the Developing Rat Brain

PubMed Central

Wang, Haiping; Ke, Zunji; Alimov, Alexander; Xu, Mei; Frank, Jacqueline A.; Fang, Shengyun; Luo, Jia

2014-01-01

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an evolutionarily conserved neurotrophic factor which exhibited neuroprotective properties. Recent studies suggested that MANF may play a role in the neural development of Drosophila and zebra fishes. In this study, we investigated the spatiotemporal expression of MANF in the brain of postnatal and adult rats. MANF expression appeared wide spread and mainly localized in neurons. In the cerebral cortex, neurons in layer IV and VI displayed particularly strong MANF immunoreactivity. In the hippocampus, intensive MANF expression was observed throughout the subfields of Cornu Amonis (CA1, CA2, and CA3) and the granular layer of the dentate gyrus (DG). In the substantia nigra, high MANF expression was shown in the substantia nigra pars compacta (SNpc). In the thalamus, the anterodorsal thalamic nucleus (ADTN) exhibited the highest MANF immunoreactivity. In the hypothalamus, intensive MANF immunoreactivity was shown in the supraoptic nucleus (SON) and tuberomammillary nucleus (TMN). In the cerebellum, MANF was localized in the external germinal layer (EGL), Purkinje cell layer (PCL), internal granule layer (IGL) and the deep cerebellar nuclei (DCN). We examined the developmental expression of MANF on postnatal day (PD) 3, 5, 7, 9, 15, 21, 30 and adulthood. In general, the levels of MANF were high in the early PDs (PD3 and PD5), and declined gradually as the brain matured; MANF expression in the adult brain was the lowest among all time points examined. However, in some structures, such as PCL, IGL, SON, TMN and locus coeruleus (LC), high expression of MANF sustained throughout the postnatal period and persisted into adulthood. Our results indicated that MANF was developmentally regulated and may play a role in the maturation of the central nervous system (CNS). PMID:24587361

The effects of polymorphisms in IL-2, IFN-γ, TGF-β2, IgL, TLR-4, MD-2, and iNOS genes on resistance to Salmonella enteritidis in indigenous chickens.

PubMed

Tohidi, Reza; Idris, Ismail Bin; Panandam, Jothi Malar; Bejo, Mohd Hair

2012-12-01

Salmonella Enteritidis is a major cause of food poisoning worldwide, and poultry products are the main source of S. Enteritidis contamination for humans. Among the numerous strategies for disease control, improving genetic resistance to S. Enteritidis has been the most effective approach. We investigated the association between S. Enteritidis burden in the caecum, spleen, and liver of young indigenous chickens and seven candidate genes, selected on the basis of their critical roles in immunological functions. The genes included those encoding interleukin 2 (IL-2), interferon-γ (IFN-γ), transforming growth factor β2 (TGF-β2), immunoglobulin light chain (IgL), toll-like receptor 4 (TLR-4), myeloid differentiation protein 2 (MD-2), and inducible nitric oxide synthase (iNOS). Two Malaysian indigenous chicken breeds were used as sustainable genetic sources of alleles that are resistant to salmonellosis. The polymerase chain reaction restriction fragment-length polymorphism technique was used to genotype the candidate genes. Three different genotypes were observed in all of the candidate genes, except for MD-2. All of the candidate genes showed the Hardy-Weinberg equilibrium for the two populations. The IL-2-MnlI polymorphism was associated with S. Enteritidis burden in the caecum and spleen. The TGF-β2-RsaI, TLR-4-Sau 96I, and iNOS-AluI polymorphisms were associated with the caecum S. Enteritidis load. The other candidate genes were not associated with S. Enteritidis load in any organ. The results indicate that the IL-2, TGF-β2, TLR-4, and iNOS genes are potential candidates for use in selection programmes for increasing genetic resistance against S. Enteritidis in Malaysian indigenous chickens.

Role of Information Anxiety and Information Load on Processing of Prescription Drug Information Leaflets.

PubMed

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.

Role of Information Anxiety and Information Load on Processing of Prescription Drug Information Leaflets

PubMed Central

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

Leaflet Area as a Determinant of Tricuspid Regurgitation Severity in Patients with Pulmonary Hypertension

PubMed Central

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

Sequential hydrophile and lipophile solubilization as an efficient method for decellularization of porcine aortic valve leaflets: Structure, mechanical property and biocompatibility study.

PubMed

Qiao, Wei-Hua; Liu, Peng; Hu, Dan; Al Shirbini, Mahmoud; Zhou, Xian-Ming; Dong, Nian-Guo

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.

Daily bread: a novel vehicle for dissemination and evaluation of psychological first aid for families exposed to armed conflict in Syria.

PubMed

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.

Effects of CO2 Concentration on Rubisco Activity, Amount, and Photosynthesis in Soybean Leaves 1

PubMed Central

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

Adjunctive intracardiac echocardiography imaging from the left ventricle to guide percutaneous mitral valve repair with the MitraClip in patients with failed prior surgical rings.

PubMed

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.

Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves

PubMed Central

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

Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves.

PubMed

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.

How much information about the benefits of medicines is included in patient leaflets in the European Union? - A survey.

PubMed

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.

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

ERIC Educational Resources Information Center

Glover-Smith, Alma

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

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…

Temperature shift experiments suggest that metabolic impairment and enhanced rates of photorespiration decrease organic acid levels in soybean leaflets exposed to supra-optimal growth temperatures

USDA-ARS?s Scientific Manuscript database

Citrate, malate, malonate, fumarate and succinate in soybean leaflets decreased 40 to 80% when plants were grown continuously in controlled environment chambers at 36/28 compared to 28/20 °C. Glycerate was not temperature responsive in this study. Temperature effects on the above mentioned organi...

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,…

How readable are Australian paediatric oral health education materials?

PubMed

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.

Systemic properties of myclobutanil in soybean plants, affecting control of Asian soybean rust (Phakopsora pachyrhizi).

PubMed

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.

Cholesterol asymmetry in synaptic plasma membranes.

PubMed

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.

First fossil evidence of Connaraceae R. Br. from Indian Cenozoic and its phytogeographical significance

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.

The enigmatic fast leaflet rotation in Desmodium motorium

PubMed Central

Lev-Yadun, Simcha

2013-01-01

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

Interaction between bending and tension forces in bilayer membranes.

PubMed Central

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

A Ruptured Mitral Valve Aneurysm as Complication of a Bicuspid Aortic Valve Endocarditis.

PubMed

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.

Repair for mitral stenosis due to pannus formation after Duran ring annuloplasty.

PubMed

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.

The enigmatic fast leaflet rotation in Desmodium motorium: butterfly mimicry for defense?

PubMed

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.

Pathophysiology of Degenerative Mitral Regurgitation: New 3-Dimensional Imaging Insights.

PubMed

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.

Large Direct Repeats Flank Genomic Rearrangements between a New Clinical Isolate of Francisella tularensis subsp. tularensis A1 and Schu S4

DTIC Science & Technology

2010-02-03

occur at locations 1,374,336–1,408,246 ( DRI ) and 1,767,671– 1,801,581 (DRII) in Schu S4. In addition, a 5358 bp segment of Table 2. VNTR markers and...iglABCD operon were found in NE061598. The location of DRI and DRII in both Schu S4 and NE061598 are shown in figures 2A and 2B. In addition, DRIII (III...loss of the first 207 bp in DRI of NE061598 (Figure 2). Similar chromosomal changes mediated by these duplicated regions were also observed between Schu

Eareckson AFS, Alaska (Formerly Shemya AFB, Alaska): 1993 Installation Restoration Program Basewide and Limited Source Investigation, Work Plan

DTIC Science & Technology

1993-12-01

porphyry intrusives that crop out along the northeast and southeast shores and locally inland. Bedrock lithology is only rarely described in the borehole...kg). Groundwater samples contained arsenic (62.8 mg/L to 66.9 mg/L), chromium (19.2 mg/L to 80 mg/L), copper (52.9 mg/L to 255 mg/L), zinc (163 mg/L...0.17 mg/L; nitrate/nitrite ranging from 0.038 mg/L to 1.41 mg/L; copper at 9.6 pg/I; zinc at 13.3 pg/L; and bis (2-ethylhexyl) phthalate at 1 /ig/L

Particle image velocimetry study of pulsatile flow in bi-leaflet mechanical heart valves with image compensation method.

PubMed

Shi, Yubing; Yeo, Tony Joon Hock; Zhao, Yong; Hwang, Ned H C

2006-12-01

Particle Image Velocimetry (PIV) is an important technique in studying blood flow in heart valves. Previous PIV studies of flow around prosthetic heart valves had different research concentrations, and thus never provided the physical flow field pictures in a complete heart cycle, which compromised their pertinence for a better understanding of the valvular mechanism. In this study, a digital PIV (DPIV) investigation was carried out with improved accuracy, to analyse the pulsatile flow field around the bi-leaflet mechanical heart valve (MHV) in a complete heart cycle. For this purpose a pulsatile flow test rig was constructed to provide the necessary in vitro test environment, and the flow field around a St. Jude size 29 bi-leaflet MHV and a similar MHV model were studied under a simulated physiological pressure waveform with flow rate of 5.2 l/min and pulse rate at 72 beats/min. A phase-locking method was applied to gate the dynamic process of valve leaflet motions. A special image-processing program was applied to eliminate optical distortion caused by the difference in refractive indexes between the blood analogue fluid and the test section. Results clearly showed that, due to the presence of the two leaflets, the valvular flow conduit was partitioned into three flow channels. In the opening process, flow in the two side channels was first to develop under the presence of the forward pressure gradient. The flow in the central channel was developed much later at about the mid-stage of the opening process. Forward flows in all three channels were observed at the late stage of the opening process. At the early closing process, a backward flow developed first in the central channel. Under the influence of the reverse pressure gradient, the flow in the central channel first appeared to be disturbed, which was then transformed into backward flow. The backward flow in the central channel was found to be the main driving factor for the leaflet rotation in the valve 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.

Development of an off bypass mitral valve repair.

PubMed

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.

Development and Evaluation of a Leaflet for Concerned Family Members and Friends: "It's Safe to Talk about Suicide"

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…

Education on tick bite and Lyme borreliosis prevention, aimed at schoolchildren in the Netherlands: comparing the effects of an online educational video game versus a leaflet or no intervention.

PubMed

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).

Effect of Losartan on Mitral Valve Changes After Myocardial Infarction.

PubMed

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.

Readability of medicinal package leaflets: a systematic review

PubMed Central

Pires, Carla; Vigário, Marina; Cavaco, Afonso

2015-01-01

OBJECTIVE To review studies on the readability of package leaflets of medicinal products for human use. METHODS We conducted a systematic literature review between 2008 and 2013 using the keywords “Readability and Package Leaflet” and “Readability and Package Insert” in the academic search engine Biblioteca do Conhecimento Online, comprising different bibliographic resources/databases. The preferred reporting items for systematic reviews and meta-analyses criteria were applied to prepare the draft of the report. Quantitative and qualitative original studies were included. Opinion or review studies not written in English, Portuguese, Italian, French, or Spanish were excluded. RESULTS We identified 202 studies, of which 180 were excluded and 22 were enrolled [two enrolling healthcare professionals, 10 enrolling other type of participants (including patients), three focused on adverse reactions, and 7 descriptive studies]. The package leaflets presented various readability problems, such as complex and difficult to understand texts, small font size, or few illustrations. The main methods to assess the readability of the package leaflet were usability tests or legibility formulae. Limitations with these methods included reduced number of participants; lack of readability formulas specifically validated for specific languages (e.g., Portuguese); and absence of an assessment on patients literacy, health knowledge, cognitive skills, levels of satisfaction, and opinions. CONCLUSIONS Overall, the package leaflets presented various readability problems. In this review, some methodological limitations were identified, including the participation of a limited number of patients and healthcare professionals, the absence of prior assessments of participant literacy, humor or sense of satisfaction, or the predominance of studies not based on role-plays about the use of medicines. These limitations should be avoided in future studies and be considered when interpreting the results. PMID:25741660

Increasing girls’ knowledge about human papillomavirus vaccination with a pre-test and a national leaflet: a quasi-experimental study

PubMed Central

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

Calcification of the mitral valve and annulus: systematic evaluation of effects on valve anatomy and function.

PubMed

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.

Fast image-based mitral valve simulation from individualized geometry.

PubMed

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.

Increasing girls' knowledge about human papillomavirus vaccination with a pre-test and a national leaflet: a quasi-experimental study.

PubMed

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.

Early Activation of Growth Pathways in Mitral Leaflets Exposed to Aortic Regurgitation: New Insights from an Animal Model.

PubMed

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.

Contribution of mitral valve leaflet length and septal wall thickness to outflow tract obstruction in patients with hypertrophic cardiomyopathy.

PubMed

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.

Leaflet area as a determinant of tricuspid regurgitation severity in patients with pulmonary hypertension.

PubMed

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.

Correction of anterior mitral prolapse: the parachute technique.

PubMed

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.

Traumatic Tricuspid Regurgitation.

PubMed

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.

Pulmonary artery dissection following balloon valvuloplasty in a dog with pulmonic stenosis.

PubMed

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.

Cooking up Psychological Operations: The Ingredients of Successful PSYOP

DTIC Science & Technology

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

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

PubMed

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

2015-08-01

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

Increasing awareness of gynecological cancer symptoms and reducing barriers to medical help seeking: does health literacy play a role?

PubMed

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.

The Islamic State Battle Plan: Press Release Natural Language Processing

DTIC Science & Technology

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

Clinical, echocardiographic, and Doppler imaging characteristics of mitral valve stenosis in two dogs.

PubMed

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.

[Valvuloplasty with balloon catheter in biologic prosthesis. Reality or illusion].

PubMed

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.

Selective propensity of bovine jugular vein material to bacterial adhesions: An in-vitro study.

PubMed

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.

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

PubMed

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.

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

Anterior Leaflet Augmentation With CorMatrix Porcine Extracellular Matrix in Twenty-Five Patients: Unexpected Patch Failures and Histologic Analysis.

PubMed

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.

Tricuspid regurgitation due to chest trauma: an unusual laceration around the annulus of the anterior leaflet.

PubMed

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.

Inward relocation of exogenous phosphatidylserine triggered by IGF-1 in non-apoptotic C2C12 cells is concentration dependent.

PubMed

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.

Reducing the Social Gradient in Uptake of the NHS Colorectal Cancer Screening Programme Using a Narrative-Based Information Leaflet: A Cluster-Randomised Trial

PubMed Central

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

A review of state-of-the-art numerical methods for simulating flow through mechanical heart valves.

PubMed

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.

P-glycoprotein substrate transport assessed by comparing cellular and vesicular ATPase activity.

PubMed

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.

A review of state-of-the-art numerical methods for simulating flow through mechanical heart valves

PubMed Central

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

Receipt and use of spoken and written over-the-counter medicine information: insights into Australian and UK consumers' experiences.

PubMed

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.

Getting to the Outer Leaflet: Physiology of Phosphatidylserine Exposure at the Plasma Membrane.

PubMed

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.

Mid-term function and remodeling potential of tissue engineered tricuspid valve: Histology and biomechanics.

PubMed

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.

Reconstruction of the right ventricular outflow tract with a bovine jugular vein graft fixed with a naturally occurring crosslinking agent (genipin) in a canine model.

PubMed

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.

Efficacy of chordal cutting in alleviating ischemic mitral regurgitation: insights from 3-dimensional echocardiography

PubMed Central

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

Efficacy of chordal cutting in alleviating ischemic mitral regurgitation: insights from 3-dimensional echocardiography.

PubMed

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.

A new definition for an old entity: improved definition of mitral valve prolapse using three-dimensional echocardiography and color-coded parametric models.

PubMed

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.

Quality assessment of patient leaflets on misoprostol-induced labour: does written information adhere to international standards for patient involvement and informed consent?

PubMed Central

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

Mitral Valve Chordae Tendineae: Topological and Geometrical Characterization.

PubMed

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.

Identification and VIGS-based characterization of Bx1 ortholog in rye (Secale cereale L.)

PubMed Central

Groszyk, Jolanta; Kowalczyk, Mariusz; Yanushevska, Yuliya; Stochmal, Anna; Rakoczy-Trojanowska, Monika

2017-01-01

The first step of the benzoxazinoid (BX) synthesis pathway is catalyzed by an enzyme with indole-3-glycerol phosphate lyase activity encoded by 3 genes, Bx1, TSA and Igl. A gene highly homologous to maize and wheat Bx1 has been identified in rye. The goal of the study was to analyze the gene and to experimentally verify its role in the rye BX biosynthesis pathway as a rye ortholog of the Bx1 gene. Expression of the gene showed peak values 3 days after imbibition (dai) and at 21 dai it was undetectable. Changes of the BX content in leaves were highly correlated with the expression pattern until 21 dai. In plants older than 21 dai despite the undetectable expression of the analyzed gene there was still low accumulation of BXs. Function of the gene was verified by correlating its native expression and virus-induced silencing with BX accumulation. Barley stripe mosaic virus (BSMV)-based vectors were used to induce transcriptional (TGS) and posttranscriptional (PTGS) silencing of the analyzed gene. Both strategies (PTGS and TGS) significantly reduced the transcript level of the analyzed gene, and this was highly correlated with lowered BX content. Inoculation with virus-based vectors specifically induced expression of the analyzed gene, indicating up-regulation by biotic stressors. This is the first report of using the BSMV-based system for functional analysis of rye gene. The findings prove that the analyzed gene is a rye ortholog of the Bx1 gene. Its expression is developmentally regulated and is strongly induced by biotic stress. Stable accumulation of BXs in plants older than 21 dai associated with undetectable expression of ScBx1 indicates that the function of the ScBx1 in the BX biosynthesis is redundant with another gene. We anticipate that the unknown gene is a putative ortholog of the Igl, which still remains to be identified in rye. PMID:28234909

Cerebellum cholinergic muscarinic receptor (subtype-2 and -3) and cytoarchitecture after developmental exposure to methylmercury: an immunohistochemical study in rat.

PubMed

Roda, Elisa; Coccini, Teresa; Acerbi, Davide; Castoldi, Anna; Bernocchi, Graziella; Manzo, Luigi

2008-05-01

The developing central nervous system (CNS) is a target of the environmental toxicant methylmercury (MeHg), and the cerebellum seems the most susceptible tissue in response to this neurotoxicant. The cholinergic system is essential for brain development, acting as a modulator of neuronal proliferation, migration and differentiation processes; its muscarinic receptors (MRs) play pivotal roles in regulating important basic physiologic functions. By immunohistochemistry, we investigated the effects of perinatal (GD7-PD21) MeHg (0.5 mg/kg bw/day in drinking water) administration on cerebellum of mature (PD36) and immature (PD21) rats, evaluating the: (i) M2- and M3-MR expression; (ii) presence of gliosis; (iii) cytoarchitecture alterations. Regarding to M2-MRs, we showed that: at PD21, MeHg-treated animals did not display any differences compared to controls, while, at PD36 there was a significant increase of M2-immunopositive Bergmann cells in the molecular layer (ML), suggesting a MeHg-related cytotoxic effect. Similarly to M2-MRs, at PD21 the M3-MRs were not affected by MeHg, while, at PD36 a lacking immunoreactivity of the granular layer (IGL) was observed after MeHg treatment. In MeHg-treated rats, at both developmental points, we showed reactive gliosis, e.g. a significant increase in Bergmann glia of the ML and astrocytes of the IGL, identified by their expression of glial fibrillar acidic protein. No MeHg-related effects on Purkinje cells were detected neither at weaning nor at puberty. These findings suggest: (i) a delayed MeHg exposure-related effect on M2- and M3-MRs, (ii) an overt MeHg-related cytotoxic effect on cerebellar oligodendroglia, e.g. reactive gliosis, (iii) a selective vulnerability of granule cells and Purkinje neurons to MeHg, with the latter that remain unharmed.

A monoclonal antibody distinguishes between two IgM heavy chain isotypes in Atlantic salmon and brown trout: protein characterization, 3D modeling and epitope mapping.

PubMed

Kamil, Atif; Falk, Knut; Sharma, Animesh; Raae, Arnt; Berven, Frode; Koppang, Erling Olaf; Hordvik, Ivar

2011-09-01

Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) possess two distinct subpopulations of IgM which can be separated by anion exchange chromatography. Accordingly, there are two isotypic μ genes in these species, related to ancestral tetraploidy. In the present work it was verified by mass spectrometry that IgM of peak 1 (subpopulation 1) have heavy chains previously designated as μB type whereas IgM of peak 2 (subpopulation 2) have heavy chains of μA type. Two adjacent cysteine residues are present near the C-terminal part of μB, in contrast to one cysteine residue in μA. Salmon IgM of both peak 1 and peak 2 contain light chains of the two most common isotypes: IgL1 and IgL3. In contrast to salmon and brown trout, IgM of rainbow trout (Oncorhynchus mykiss) is eluted in a single peak when subjected to anion exchange chromatography. Surprisingly, a monoclonal antibody MAb4C10 against rainbow trout IgM, reacted with μA in salmon, whereas in brown trout it reacted with μB. It is plausible to assume that DNA has been exchanged between the paralogous A and B loci during evolution while maintaining the two sub-variants, with and without the extra cysteine. MAb4C10 was conjugated to magnetic beads and used to separate cells, demonstrating that μ transcripts residing from captured cells were primarily of A type in salmon and B type in brown trout. An analysis of amino acid substitutions in μA and μB of salmon and brown trout indicated that the third constant domain is essential for MAb4C10 binding. This was supported by 3D modeling and was finally verified by studies of MAb4C10 reactivity with a series of recombinant μ3 constructs. Copyright © 2011 Elsevier Ltd. All rights reserved.

Identification and VIGS-based characterization of Bx1 ortholog in rye (Secale cereale L.).

PubMed

Groszyk, Jolanta; Kowalczyk, Mariusz; Yanushevska, Yuliya; Stochmal, Anna; Rakoczy-Trojanowska, Monika; Orczyk, Waclaw

2017-01-01

The first step of the benzoxazinoid (BX) synthesis pathway is catalyzed by an enzyme with indole-3-glycerol phosphate lyase activity encoded by 3 genes, Bx1, TSA and Igl. A gene highly homologous to maize and wheat Bx1 has been identified in rye. The goal of the study was to analyze the gene and to experimentally verify its role in the rye BX biosynthesis pathway as a rye ortholog of the Bx1 gene. Expression of the gene showed peak values 3 days after imbibition (dai) and at 21 dai it was undetectable. Changes of the BX content in leaves were highly correlated with the expression pattern until 21 dai. In plants older than 21 dai despite the undetectable expression of the analyzed gene there was still low accumulation of BXs. Function of the gene was verified by correlating its native expression and virus-induced silencing with BX accumulation. Barley stripe mosaic virus (BSMV)-based vectors were used to induce transcriptional (TGS) and posttranscriptional (PTGS) silencing of the analyzed gene. Both strategies (PTGS and TGS) significantly reduced the transcript level of the analyzed gene, and this was highly correlated with lowered BX content. Inoculation with virus-based vectors specifically induced expression of the analyzed gene, indicating up-regulation by biotic stressors. This is the first report of using the BSMV-based system for functional analysis of rye gene. The findings prove that the analyzed gene is a rye ortholog of the Bx1 gene. Its expression is developmentally regulated and is strongly induced by biotic stress. Stable accumulation of BXs in plants older than 21 dai associated with undetectable expression of ScBx1 indicates that the function of the ScBx1 in the BX biosynthesis is redundant with another gene. We anticipate that the unknown gene is a putative ortholog of the Igl, which still remains to be identified in rye.

Basic Mechanisms of Mitral Regurgitation

PubMed Central

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

Effects of suture position on left ventricular fluid mechanics under mitral valve edge-to-edge repair.

PubMed

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.

Dynamic behavior of prosthetic aortic tissue valves as viewed by high-speed cinematography.

PubMed

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.

Tissue Doppler imaging and echo-Doppler findings associated with a mitral valve stenosis with an immobile posterior valve leaflet in a bull terrier.

PubMed

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.

Mitral valve plasty for mitral regurgitation after blunt chest trauma.

PubMed

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.

Design of Bioprosthetic Aortic Valves using biaxial test data.

PubMed

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.

Enzyme structures of the bacterial peptidoglycan and wall teichoic acid biogenesis pathways.

PubMed

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.

Live/real time three-dimensional transthoracic echocardiographic assessment of tricuspid valve pathology: incremental value over the two-dimensional technique.

PubMed

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.

Asymmetric distribution of charged lipids between the leaflets of a vesicle bilayer induced by melittin and alamethicin

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

Assay for the transbilayer distribution of glycolipids. Selective oxidation of glucosylceramide to glucuronylceramide by TEMPO nitroxyl radicals.

PubMed

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.

How are service users instructed to measure home furniture for provision of minor assistive devices?

PubMed

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.

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

PubMed

Yamamoto, Michiko; Doi, Hirohisa; Furukawa, Aya

2015-01-01

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

Modifications in plasma membrane lipid composition and morphological features of AH-130 hepatoma cells by polyenylphosphatidylcholine in vivo treatment.

PubMed

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.

Arthroscopic partial meniscectomy of a posteriorly flipped superior leaflet in a horizontal medial meniscus tear using a posterior transseptal portal.

PubMed

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.

Acquisition and diversification of tendrilled leaves in Bignonieae (Bignoniaceae) involved changes in expression patterns of SHOOTMERISTEMLESS (STM), LEAFY/FLORICAULA (LFY/FLO), and PHANTASTICA (PHAN).

PubMed

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.

Design considerations and quantitative assessment for the development of percutaneous mitral valve stent.

PubMed

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.

A finite element model on effects of impact load and cavitation on fatigue crack propagation in mechanical bileaflet aortic heart valve.

PubMed

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.

Costs and difficulties of recruiting patients to provide e-health support: pilot study in one primary care trust.

PubMed

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.

New graft sizing rings for aortic valve reimplantation procedures.

PubMed

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.

Fluid-structure interaction of a pulsatile flow with an aortic valve model: A combined experimental and numerical study.

PubMed

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.

IFITM3 Restricts Influenza A Virus Entry by Blocking the Formation of Fusion Pores following Virus-Endosome Hemifusion

PubMed Central

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

The evaluation of materials to provide health-related information as a population strategy in the worksite: The high-risk and population strategy for occupational health promotion (HIPOP-OHP) study.

PubMed

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.

Role of phosphatidylserine in phospholipid flippase-mediated vesicle transport in Saccharomyces cerevisiae.

PubMed

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.

Lipid diffusion in the distal and proximal leaflets of supported lipid bilayer membranes studied by single particle tracking

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.

Watchful waiting or induction of labour--a matter of informed choice: identification, analysis and critical appraisal of decision aids and patient information regarding care options for women with uncomplicated singleton late and post term pregnancies: a review.

PubMed

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.

Robotic artificial chordal replacement for repair of mitral valve prolapse.

PubMed

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.

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

PubMed

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

2014-03-01

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

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.

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.

The 'sail sound' and tricuspid regurgitation in Ebstein's anomaly: the value of echocardiography in evaluating their mechanisms.

PubMed

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.

The Free Energy of Small Solute Permeation through the Escherichia coli Outer Membrane Has a Distinctly Asymmetric Profile

DOE PAGES

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

The Free Energy of Small Solute Permeation through the Escherichia coli Outer Membrane Has a Distinctly Asymmetric Profile

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

Modeling the Mitral Valve

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.

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.

Can Low-Cost Strategies Improve Attendance Rates in Brief Psychological Therapy? Double-Blind Randomized Controlled Trial.

PubMed

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.

Novel pathogenetic mechanisms and structural adaptations in ischemic mitral regurgitation.

PubMed

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.

An experimental-computational analysis of MHV cavitation: effects of leaflet squeezing and rebound.

PubMed

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.

[Communication prostheses and behavioral alignment in hospital leaflets].

PubMed

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.

Complementary probes reveal that phosphatidylserine is required for the proper transbilayer distribution of cholesterol.

PubMed

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.

Tricuspid and Mitral Valve Regurgitation with Bi-fascicular Block Following a Horse Kick.

PubMed

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.

Biochemical nature of Russell Bodies

PubMed Central

Francesca Mossuto, Maria; Ami, Diletta; Anelli, Tiziana; Fagioli, Claudio; Maria Doglia, Silvia; Sitia, Roberto

2015-01-01

Professional secretory cells produce and release abundant proteins. Particularly in case of mutations and/or insufficient chaperoning, these can aggregate and become toxic within or amongst cells. Immunoglobulins (Ig) are no exception. In the extracellular space, certain Ig-L chains form fibrils causing systemic amyloidosis. On the other hand, Ig variants lacking the first constant domain condense in dilated cisternae of the early secretory compartment, called Russell Bodies (RB), frequently observed in plasma cell dyscrasias, autoimmune diseases and chronic infections. RB biogenesis can be recapitulated in lymphoid and non-lymphoid cells by expressing mutant Ig-μ, providing powerful models to investigate the pathophysiology of endoplasmic reticulum storage disorders. Here we analyze the aggregation propensity and the biochemical features of the intra- and extra-cellular Ig deposits in human cells, revealing β-aggregated features for RB. PMID:26223695

Biochemical nature of Russell Bodies.

PubMed

Mossuto, Maria Francesca; Ami, Diletta; Anelli, Tiziana; Fagioli, Claudio; Doglia, Silvia Maria; Sitia, Roberto

2015-07-30

Professional secretory cells produce and release abundant proteins. Particularly in case of mutations and/or insufficient chaperoning, these can aggregate and become toxic within or amongst cells. Immunoglobulins (Ig) are no exception. In the extracellular space, certain Ig-L chains form fibrils causing systemic amyloidosis. On the other hand, Ig variants lacking the first constant domain condense in dilated cisternae of the early secretory compartment, called Russell Bodies (RB), frequently observed in plasma cell dyscrasias, autoimmune diseases and chronic infections. RB biogenesis can be recapitulated in lymphoid and non-lymphoid cells by expressing mutant Ig-μ, providing powerful models to investigate the pathophysiology of endoplasmic reticulum storage disorders. Here we analyze the aggregation propensity and the biochemical features of the intra- and extra-cellular Ig deposits in human cells, revealing β-aggregated features for RB.

Correlations with operative anatomy of real time three-dimensional echocardiographic imaging of congenital aortic valvar stenosis.

PubMed

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.

Patients in need of medicine information.

PubMed

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.

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.

In vivo evaluation of an in-body, tissue-engineered, completely autologous valved conduit (biovalve type VI) as an aortic valve in a goat model.

PubMed

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.

Ovarian and cervical cancer awareness: development of two validated measurement tools.

PubMed

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.

Ovarian and cervical cancer awareness: development of two validated measurement tools

PubMed Central

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

Mitral valve morphology assessed by three-dimensional transthoracic echocardiography in healthy dogs and dogs with myxomatous mitral valve disease.

PubMed

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.

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

PubMed

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

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

Preparation, validation and user-testing of pictogram-based patient information leaflets for tuberculosis.

PubMed

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.

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

PubMed

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

2016-07-01

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

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

PubMed Central

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

2016-01-01

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

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

Morphometric features of the right atrioventricular orifice in adult human hearts.

PubMed

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.

Does an information leaflet about surgical site infection (SSI) improve recollection of information and satisfaction of patients? A randomized trial in patients scheduled for digestive surgery.

PubMed

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.

Insufficient Leaflet Remodeling in Patients With Atrial Fibrillation: Association With the Severity of Mitral Regurgitation.

PubMed

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.

Locomotor activity and non-photic influences on circadian clocks.

PubMed

Mrosovsky, N

1996-08-01

Some of the main themes in this review are as follows. 1. The notion that non-photic zeitgebers are weak needs re-examining. Phase-shifts to some non-photic manipulations can be as large as those to light pulses. 2. As well as being able to phase-shift and entrain free-running rhythms, non-photic events have a number of other effects: these include after-effects of entrainment, period changes, and promotion of splitting. 3. The critical variable for non-photic shifting is unknown. Locomotor activity is more likely to be an index of some other necessary state rather than being causal itself. This index may be better when tendencies to move are channelled into easily measured behaviours like wheel-running. 4. Given ignorance about the critical variable, quantification of activity may be the best presently available measure of zeitgeber intensity. Therefore, the behaviour during non-photic manipulations must be examined as carefully as the shifts themselves. When no phase-shifting follows manipulations such as IGL lesions or serotonin depletion, if the animals are inactive, then little can be inferred. 5. Lack of information on the critical variable(s) for non-photic shifting makes it problematic to compare data from studies using different non-photic manipulations. However, the presence of locomotor activity (or its correlate) does appear to be necessary for triazolam to produce shifts. 6. Novelty-induced wheel-running in hamsters depends on the NPY projection from the IGL to SCN. It remains to be determined how important NPY is in other species or in clock-resetting by other manipulations, but methods are now available to study this. 7. Interactions between photic and non-photic zeitgebers remain virtually unexplored, but it is evident that photic and non-photic stimuli can attenuate the phase-shifting effects of each other. Interactions are not purely additive or predictable from PRCs. 8. The circadian system does more than synchronize free-running rhythms to the solar day. Its non-photic functions and their interactions with photic inputs probably account for some of the anatomical complexity of circadian circuitry.

Diversity of the murine antibody response targeting influenza A(H1N1pdm09) hemagglutinin

PubMed Central

Wilson, Jason R.; Tzeng, Wen-Pin; Spesock, April; Music, Nedzad; Guo, Zhu; Barrington, Robert; Stevens, James; Donis, Ruben O.; Katz, Jacqueline M.; York, Ian A.

2016-01-01

We infected mice with the 2009 influenza A pandemic virus (H1N1pdm09), boosted with an inactivated vaccine, and cloned immunoglobulins (Igs) from HA-specific B cells. Based on the redundancy in germline gene utilization, we inferred that between 72–130 unique IgH VDJ and 35 different IgL VJ combinations comprised the anti-HA recall response. The IgH VH1 and IgL VK14 variable gene families were employed most frequently. A representative panel of antibodies were cloned and expressed to confirm reactivity with H1N1pdm09 HA. The majority of the recombinant antibodies were of high avidity and capable of inhibiting H1N1pdm09 hemagglutination. Three of these antibodies were subtype-specific cross-reactive, binding to the HA of A/South Carolina/1/1918(H1N1), and one further reacted with A/swine/Iowa/15/1930(H1N1). These results help define the genetic diversity of the influenza anti-HA antibody repertoire profile induced following infection and vaccination, which may facilitate the development of influenza vaccines that are more protective and broadly neutralizing. Importance Protection against influenza viruses is mediated mainly by antibodies, and in most cases this antibody response is narrow, only providing protection against closely-related viruses. In spite of this limited range of protection, recent findings indicate individuals immune to one influenza virus may contain antibodies (generally a minority of the overall response) that are more broadly reactive. These findings have raised the possibility that influenza vaccines could induce a more broadly protective response, reducing the need for frequent vaccine strain changes. However, interpretation of these observations is hampered by the lack of quantitative characterization of the antibody repertoire. In this study, we used single-cell cloning of influenza HA-specific B cells to assess the diversity and nature of the antibody response to influenza hemagglutinin in mice. Our findings help put bounds on the diversity of the anti-hemagglutinin antibody response, as well as characterizing the cross-reactivity, affinity, and molecular nature of the antibody response. PMID:24928044

Diversity of the murine antibody response targeting influenza A(H1N1pdm09) hemagglutinin.

PubMed

Wilson, Jason R; Tzeng, Wen-Pin; Spesock, April; Music, Nedzad; Guo, Zhu; Barrington, Robert; Stevens, James; Donis, Ruben O; Katz, Jacqueline M; York, Ian A

2014-06-01

We infected mice with the 2009 influenza A pandemic virus (H1N1pdm09), boosted with an inactivated vaccine, and cloned immunoglobulins (Igs) from HA-specific B cells. Based on the redundancy in germline gene utilization, we inferred that between 72-130 unique IgH VDJ and 35 different IgL VJ combinations comprised the anti-HA recall response. The IgH VH1 and IgL VK14 variable gene families were employed most frequently. A representative panel of antibodies were cloned and expressed to confirm reactivity with H1N1pdm09 HA. The majority of the recombinant antibodies were of high avidity and capable of inhibiting H1N1pdm09 hemagglutination. Three of these antibodies were subtype-specific cross-reactive, binding to the HA of A/South Carolina/1/1918(H1N1), and one further reacted with A/swine/Iowa/15/1930(H1N1). These results help to define the genetic diversity of the influenza anti-HA antibody repertoire profile induced following infection and vaccination, which may facilitate the development of influenza vaccines that are more protective and broadly neutralizing. Protection against influenza viruses is mediated mainly by antibodies, and in most cases this antibody response is narrow, only providing protection against closely related viruses. In spite of this limited range of protection, recent findings indicate that individuals immune to one influenza virus may contain antibodies (generally a minority of the overall response) that are more broadly reactive. These findings have raised the possibility that influenza vaccines could induce a more broadly protective response, reducing the need for frequent vaccine strain changes. However, interpretation of these observations is hampered by the lack of quantitative characterization of the antibody repertoire. In this study, we used single-cell cloning of influenza HA-specific B cells to assess the diversity and nature of the antibody response to influenza hemagglutinin in mice. Our findings help to put bounds on the diversity of the anti-hemagglutinin antibody response, as well as characterizing the cross-reactivity, affinity, and molecular nature of the antibody response. Copyright © 2014 Elsevier Inc. All rights reserved.

A new species of Erythrostemon (Leguminosae, Caesalpinioideae) from the western Río Balsas Depression, Mexico.

PubMed

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.

Phylogenetic relationships among morphotypes of Caesalpinia echinata Lam. (Caesalpinioideae: Leguminosae) evidenced by trnL intron sequences

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.

Malformation of the canine mitral valve complex.

PubMed

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).

Educational posters and leaflets on leprosy: raising awareness of leprosy for health-care workers in rural South Africa.

PubMed

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.

Health literacy in pressure injury: Findings from a mixed-methods study of community-based patients and carers.

PubMed

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.

Implementation of a quality assurance process for non-therapeutic infant male circumcision providers in North West England.

PubMed

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.

Cardiolipin Prevents Membrane Translocation and Permeabilization by Daptomycin*

PubMed Central

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

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

DOE PAGES

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

2015-07-29

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

Using the Localized Surface Plasmon Resonance of Gold Nanoparticles to Monitor Lipid Membrane Assembly and Protein Binding.

PubMed

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.

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

PubMed Central

Fujimoto, Toyoshi; Parmryd, Ingela

2017-01-01

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

Krox20 defines a subpopulation of cardiac neural crest cells contributing to arterial valves and bicuspid aortic valve.

PubMed

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.

Real-time 3D visualization of cellular rearrangements during cardiac valve formation

PubMed Central

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

Arsenic transformation and plant growth promotion characteristics of As-resistant endophytic bacteria from As-hyperaccumulator Pteris vittata.

PubMed

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.

Differential solubilization of inner plasma membrane leaflet components by Lubrol WX and Triton X-100.

PubMed

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.

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.

Characterization of mechanical properties of pericardium tissue using planar biaxial tension and flexural deformation.

PubMed

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.

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

PubMed

Fujimoto, Toyoshi; Parmryd, Ingela

2016-01-01

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

Real-time 3D visualization of cellular rearrangements during cardiac valve formation.

PubMed

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.

The closing behavior of mechanical aortic heart valve prostheses.

PubMed

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.

Finite element analysis for edge-to-edge technique to treat post-mitral valve repair systolic anterior motion.

PubMed

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.

The Fluid Mechanics of Transcatheter Heart Valve Leaflet Thrombosis in the Neosinus.

PubMed

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

2017-10-24

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.

Exergames versus self-regulated exercises with instruction leaflets to improve adherence during geriatric rehabilitation: a randomized controlled trial.

PubMed

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.

A cross-sectional survey assessing factors associated with reading cancer screening information: previous screening behaviour, demographics and decision-making style.

PubMed

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.

Costs and difficulties of recruiting patients to provide e-health support: pilot study in one primary care trust

PubMed Central

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

Operation GREENHOUSE. Scientific Director’s Report of Atomic Weapon Tests at Eniwetok, 1951. Annex 1.3. Thermal Radiation Measurements. Part 1. Atmospheric Transmission. Part 2. Total Thermal Radiation. Part 3. Radiant Power as a Function of Time--Photoelectric Measurements. Appendix A and Appendix B

DTIC Science & Technology

1985-09-01

derived in the article by Stewart and Curcio. 1 In this expression, e is the angular diameter (in radians) of the field of view of the detecting...t dt = Ftdt (1) where t is the angular deflection of the galvanometer at time t; Ft is the radiant thermal en- ergy, in watts/cm’, incident n the...tits igl~ *ING ma Z.9 .Io - OEaM, * ’Uv I 82* 16. 6 O~vS v 4.vS I 0.0 vst , SO- L900 6 IS* los - low tows S~ wows; V. ) S .14t; .6;slows -~ ’.3 ’.3

Tricuspid regurgitation in patients with pacemakers and implantable cardiac defibrillators: a comprehensive review.

PubMed

Al-Bawardy, Rasha; Krishnaswamy, Amar; Bhargava, Mandeep; Dunn, Justin; Wazni, Oussama; Tuzcu, E Murat; Stewart, William; Kapadia, Samir R

2013-05-01

Implantable cardiac devices, including defibrillators and pacemakers, may be the cause of tricuspid regurgitation (TR) or may worsen existing TR. This review of the literature suggests that TR usually occurs over time after lead implantation. Diagnosis by clinical exam and 2-dimensional echocardiography may be augmented by 3-dimensional echocardiography and/or computed tomography. The mechanism may be mechanical perforation or laceration of leaflets, scarring and restriction of leaflets, or asynchronized activation of the right ventricle. Pacemaker-related TR might cause severe right-sided heart failure, but data regarding associated mortality are lacking. This comprehensive review summarizes the data regarding incidence, mechanism, and treatment of lead-related TR. © 2013 Wiley Periodicals, Inc.

A new species of Erythrostemon (Leguminosae, Caesalpinioideae) from the western Río Balsas Depression, Mexico

PubMed Central

Sotuyo, Solange; Contreras-Jiménez, José Luis; Lewis, Gwilym P.

2017-01-01

Abstract 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. PMID:28228685

Mitral stenosis due to dynamic clip-leaflet interaction during the MitraClip procedure: Case report and review of current knowledge.

PubMed

Singh, Gagan D; Smith, Thomas W; Rogers, Jason H

2017-06-01

The goal of MitraClip therapy is to achieve mitral regurgitation reduction without iatrogenic creation of clinically significant MS. In some series, up to 35% of patients are left with mild MS. There are many contributors to the final transmitral gradient achieved in patients undergoing MitraClip therapy. Additionally, there are many modalities used for the intraprocedural assessment of MS with no one modality considered to be the benchmark. We herein describe a case which illustrates the dynamic nature of clip-leaflet interaction, and review intraprocedural techniques for invasively and noninvasively assessing MS. Copyright © 2016 Elsevier Inc. All rights reserved.

Phase transition behaviors of the supported DPPC bilayer investigated by sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM).

PubMed

Wu, Heng-Liang; Tong, Yujin; Peng, Qiling; Li, Na; Ye, Shen

2016-01-21

The phase transition behaviors of a supported bilayer of dipalmitoylphosphatidyl-choline (DPPC) have been systematically evaluated by in situ sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM). By using an asymmetric bilayer composed of per-deuterated and per-protonated monolayers, i.e., DPPC-d75/DPPC and a symmetric bilayer of DPPC/DPPC, we were able to probe the molecular structural changes during the phase transition process of the lipid bilayer by SFG spectroscopy. It was found that the DPPC bilayer is sequentially melted from the top (adjacent to the solution) to bottom leaflet (adjacent to the substrate) over a wide temperature range. The conformational ordering of the supported bilayer does not decrease (even slightly increases) during the phase transition process. The conformational defects in the bilayer can be removed after the complete melting process. The phase transition enthalpy for the bottom leaflet was found to be approximately three times greater than that for the top leaflet, indicating a strong interaction of the lipids with the substrate. The present SFG and AFM observations revealed similar temperature dependent profiles. Based on these results, the temperature-induced structural changes in the supported lipid bilayer during its phase transition process are discussed in comparison with previous studies.

Traumatic rupture of the tricuspid valve and multi-modality imaging

PubMed Central

Corneli, Mariana; Conde, Diego; Ronderos, Ricardo

2014-01-01

Introduction Motor vehicle accident (MVA) account for most cases of traumatic rupture of the tricuspid valve. Valve rupture during an MVA is generated by an abrupt deceleration coupled with an increase in right-side cardiac pressures (Valsalva maneuver and thorax compression). Case A 39-year-old asymptomatic man was referred for an echocardiogram due to the presence of a systolic murmur. He had no prior significant medical history, except for a remote MVA 3 years ago. Real-time 3D echocardiography (RT3DE) showed a tear in the body of the anterior leaflet and not at the cord, as was suggested by two-dimensional transthoracic echocardiography (2D-TTE). Based on these findings, the mechanism was considered anterior leaflet rupture of the tricuspid valve, secondary to chest blunt trauma. The anterior leaflet was repaired using two polytetrafluoroethylene sutures, and tricuspid annuloplasty with an Edwards ring was performed. Conclusions Multimodality imaging helps to determine timing of surgery in asymptomatic traumatic tricuspid rupture. The combination of echocardiography and magnetic resonance imaging provide information of volumetric data and contractility of the right ventricle (RV) during follow-up. RT3DE gives information relevant to the morphological and functional characterization of the valve, allowing the planning of appropriate surgical procedure. PMID:25414827

The Lγ Phase of Pulmonary Surfactant.

PubMed

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.

Morphological leaf variability in natural populations of Pistacia atlantica Desf. subsp. atlantica along climatic gradient: new features to update Pistacia atlantica subsp. atlantica key.

PubMed

El Zerey-Belaskri, Asma; Benhassaini, Hachemi

2016-04-01

The effect of bioclimate range on the variation in Pistacia atlantica Desf. subsp. atlantica leaf morphology was studied on 16 sites in Northwest Algeria. The study examined biometrically mature leaves totaling 3520 compound leaves. Fifteen characters (10 quantitative and 5 qualitative) were assessed on each leaf. For each quantitative character, the nested analysis of variance (ANOVA) was used to examine relative magnitude of variation at each level of the nested hierarchy. The correlation between the climatic parameters and the leaf morphology was examined. The statistical analysis applied on the quantitative leaf characters showed highly significant variation at the within-site level and between-site variation. The correlation coefficient (r) showed also an important correlation between climatic parameters and leaf morphology. The results of this study exhibited several values reported for the first time on the species, such as the length and the width of the leaf (reaching up to 24.5 cm/21.9 cm), the number of leaflets (up to 18 leaflets/leaf), and the petiole length of the terminal leaflet (reaching up to 3.4 cm). The original findings of this study are used to update the P. atlantica subsp. atlantica identification key.

Mitral stenosis in 15 dogs.

PubMed

Lehmkuhl, L B; Ware, W A; Bonagura, J D

1994-01-01

Mitral stenosis was diagnosed in 15 young to middle-aged dogs. There were 5 Newfoundlands and 4 bull terriers affected, suggesting a breed predisposition for this disorder. Clinical signs included cough, dyspnea, exercise intolerance, and syncope. Soft left apical diastolic murmurs were heard only in 4 dogs, whereas 8 dogs had systolic murmurs characteristic of mitral regurgitation. Left atrial enlargement was the most prominent radiographic feature. Left-sided congestive heart failure was detected by radiographs in 11 dogs within 1 year of diagnosis. Electrocardiographic abnormalities varied among dogs and included atrial and ventricular enlargement, as well as atrial and ventricular arrhythmias. Abnormalities on M-mode and two-dimensional echocardiograms included abnormal diastolic motion of the mitral valve characterized by decreased leaflet separation, valve doming, concordant motion of the parietal mitral valve leaflet, and a decreased E-to-F slope. Increased mitral valve inflow velocities and prolonged pressure half-times were detected by Doppler echocardiography. Cardiac catheterization, performed in 8 dogs, documented a diastolic pressure gradient between the left atrial, pulmonary capillary wedge, or pulmonary artery diastolic pressures and the left ventricular diastolic pressure. Necropsy showed mitral stenosis caused by thickened, fused mitral valve leaflets in 5 dogs and a supramitral ring in another dog. The outcome in affected dogs was poor; 9 of 15 dogs were euthanatized or died by 2 1/2 years of age.

Evaluation of drug information for cardiology patients.

PubMed Central

Baker, D; Roberts, D E; Newcombe, R G; Fox, K A

1991-01-01

1. Cardiologists and pharmacists at the University Hospital of Wales collaborated to write 20 individual leaflets incorporating guidelines for a range of drugs used in the treatment of cardiology patients. The Plain English Campaign advised on the intelligibility and presentation of the information. 2. One hundred and twenty-five patients from the Regional Cardiology Unit, University Hospital of Wales were randomly allocated to receive usual verbal counselling about their drug treatment with or without an individualised drug information wallet. Two weeks after discharge from hospital patients completed a postal questionnaire to determine their satisfaction with the information about their drug treatment and their understanding of it. Forty-nine questionnaires were returned from the leaflet group and 52 from the control group. 3. The provision of written guidelines resulted in significant improvements in patients' satisfaction with their drug treatment (chi 2 = 33.3, P less than 0.001) and their understanding of it (P less than 0.001, Mann-Whitney test). Overall, patients who received leaflets were more likely to be aware of the potential side effects of their drugs but less likely to be apprehensive about them. Succinct guidelines concerning drug therapy can be assimilated by cardiology patients and provide them with a permanent record for future reference. PMID:1888619

Design and efficacy of a single-use bioreactor for heart valve tissue engineering.

PubMed

Converse, Gabriel L; Buse, Eric E; Neill, Kari R; McFall, Christopher R; Lewis, Holley N; VeDepo, Mitchell C; Quinn, Rachael W; Hopkins, Richard A

2017-02-01

Heart valve tissue engineering offers the promise of improved treatments for congenital heart disorders; however, widespread clinical availability of a tissue engineered heart valve (TEHV) has been hindered by scientific and regulatory concerns, including the lack of a disposable, bioreactor system for nondestructive valve seeding and mechanical conditioning. Here we report the design for manufacture and the production of full scale, functional prototypes of such a system. To evaluate the efficacy of this bioreactor as a tool for seeding, ovine aortic valves were decellularized and subjected to seeding with human mesenchymal stem cells (hMSC). The effects of pulsatile conditioning using cyclic waveforms tuned to various negative and positive chamber pressures were evaluated, with respect to the seeding of cells on the decellularized leaflet and the infiltration of seeded cells into the interstitium of the leaflet. Infiltration of hMSCs into the aortic valve leaflet was observed following 72 h of conditioning under negative chamber pressure. Additional conditioning under positive pressure improved cellular infiltration, while retaining gene expression within the MSC-valve interstitial cell phenotype lineage. This protocol resulted in a subsurface pilot population of cells, not full tissue recellularization. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 249-259, 2017. © 2015 Wiley Periodicals, Inc.

Subvalvular Pannus Overgrowth after Mosaic Bioprosthesis Implantation in the Aortic Position

PubMed Central

Isomura, Tadashi; Yoshida, Minoru; Katsumata, Chieko; Ito, Fusahiko; Watanabe, Masazumi

2015-01-01

Purpose: Although pannus overgrowth by itself was not the pathology of structural valve deterioration (SVD), it might be related to reoperation for SVD of the bioprostheses. Methods: We retrospectively reviewed patients undergoing reoperation for SVD after implantation of the third-generation Mosaic aortic bioprosthesis and macroscopic appearance of the explanted valves was examined to detect the presence of pannus. Results: There were 10 patients and the age for the initial aortic valve replacement was 72 ± 10 years old. The duration of durability was 9.9 ± 2.0 years. Deteriorated valve presented stenosis (valvular area of 0.96 ± 0.20 cm2; pressure gradient of 60 ± 23 mmHg). Coexisting regurgitant flow was detected in two cases. Macroscopically, subvalvular pannus overgrowth was detected in 8 cases (80%). The proportion of overgrowth from the annulus was almost even and pannus overgrowth created subvalvular membrane, which restricted the area especially for each commissure. In contrast, opening and mobility of each leaflet was not severely limited and pannus overgrowth would restrict the area, especially for each commissure. In other two cases with regurgitation, tear of the leaflet on the stent strut was detected and mild calcification of each leaflet restricted opening. Conclusion: In patients with the Mosaic aortic bioprosthesis, pannus overgrowth was the major cause for reoperation. PMID:26633541

Subvalvular Pannus Overgrowth after Mosaic Bioprosthesis Implantation in the Aortic Position.

PubMed

Hirota, Masanori; Isomura, Tadashi; Yoshida, Minoru; Katsumata, Chieko; Ito, Fusahiko; Watanabe, Masazumi

2016-01-01

Although pannus overgrowth by itself was not the pathology of structural valve deterioration (SVD), it might be related to reoperation for SVD of the bioprostheses. We retrospectively reviewed patients undergoing reoperation for SVD after implantation of the third-generation Mosaic aortic bioprosthesis and macroscopic appearance of the explanted valves was examined to detect the presence of pannus. There were 10 patients and the age for the initial aortic valve replacement was 72 ± 10 years old. The duration of durability was 9.9 ± 2.0 years. Deteriorated valve presented stenosis (valvular area of 0.96 ± 0.20 cm(2); pressure gradient of 60 ± 23 mmHg). Coexisting regurgitant flow was detected in two cases. Macroscopically, subvalvular pannus overgrowth was detected in 8 cases (80%). The proportion of overgrowth from the annulus was almost even and pannus overgrowth created subvalvular membrane, which restricted the area especially for each commissure. In contrast, opening and mobility of each leaflet was not severely limited and pannus overgrowth would restrict the area, especially for each commissure. In other two cases with regurgitation, tear of the leaflet on the stent strut was detected and mild calcification of each leaflet restricted opening. In patients with the Mosaic aortic bioprosthesis, pannus overgrowth was the major cause for reoperation.

The Impact of Fluid Inertia on In Vivo Estimation of Mitral Valve Leaflet Constitutive Properties and Mechanics.

PubMed

Bark, David L; Dasi, Lakshmi P

2016-05-01

We examine the influence of the added mass effect (fluid inertia) on mitral valve leaflet stress during isovolumetric phases. To study this effect, oscillating flow is applied to a flexible membrane at various frequencies to control inertia. Resulting membrane strain is calculated through a three-dimensional reconstruction of markers from stereo images. To investigate the effect in vivo, the analysis is repeated on a published dataset for an ovine mitral valve (Journal of Biomechanics 42(16): 2697-2701). The membrane experiment demonstrates that the relationship between pressure and strain must be corrected with a fluid inertia term if the ratio of inertia to pressure differential approaches 1. In the mitral valve, this ratio reaches 0.7 during isovolumetric contraction for an acceleration of 6 m/s(2). Acceleration is reduced by 72% during isovolumetric relaxation. Fluid acceleration also varies along the leaflet during isovolumetric phases, resulting in spatial variations in stress. These results demonstrate that fluid inertia may be the source of the temporally and spatially varying stiffness measurements previously seen through inverse finite element analysis of in vivo data during isovolumetric phases. This study demonstrates that there is a need to account for added mass effects when analyzing in vivo constitutive relationships of heart valves.

Heart valve scaffold fabrication: Bioinspired control of macro-scale morphology, mechanics and micro-structure.

PubMed

D'Amore, Antonio; Luketich, Samuel K; Raffa, Giuseppe M; Olia, Salim; Menallo, Giorgio; Mazzola, Antonino; D'Accardi, Flavio; Grunberg, Tamir; Gu, Xinzhu; Pilato, Michele; Kameneva, Marina V; Badhwar, Vinay; Wagner, William R

2018-01-01

Valvular heart disease is currently treated with mechanical valves, which benefit from longevity, but are burdened by chronic anticoagulation therapy, or with bioprosthetic valves, which have reduced thromboembolic risk, but limited durability. Tissue engineered heart valves have been proposed to resolve these issues by implanting a scaffold that is replaced by endogenous growth, leaving autologous, functional leaflets that would putatively eliminate the need for anticoagulation and avoid calcification. Despite the diversity in fabrication strategies and encouraging results in large animal models, control over engineered valve structure-function remains at best partial. This study aimed to overcome these limitations by introducing double component deposition (DCD), an electrodeposition technique that employs multi-phase electrodes to dictate valve macro and microstructure and resultant function. Results in this report demonstrate the capacity of the DCD method to simultaneously control scaffold macro-scale morphology, mechanics and microstructure while producing fully assembled stent-less multi-leaflet valves composed of microscopic fibers. DCD engineered valve characterization included: leaflet thickness, biaxial properties, bending properties, and quantitative structural analysis of multi-photon and scanning electron micrographs. Quasi-static ex-vivo valve coaptation testing and dynamic organ level functional assessment in a pressure pulse duplicating device demonstrated appropriate acute valve functionality. Copyright © 2017. Published by Elsevier Ltd.

Asymmetric phospholipid: lipopolysaccharide bilayers; a Gram-negative bacterial outer membrane mimic

PubMed Central

Clifton, Luke A.; Skoda, Maximilian W. A.; Daulton, Emma L.; Hughes, Arwel V.; Le Brun, Anton P.; Lakey, Jeremy H.; Holt, Stephen A.

2013-01-01

The Gram-negative bacterial outer membrane (OM) is a complex and highly asymmetric biological barrier but the small size of bacteria has hindered advances in in vivo examination of membrane dynamics. Thus, model OMs, amenable to physical study, are important sources of data. Here, we present data from asymmetric bilayers which emulate the OM and are formed by a simple two-step approach. The bilayers were deposited on an SiO2 surface by Langmuir–Blodgett deposition of phosphatidylcholine as the inner leaflet and, via Langmuir–Schaefer deposition, an outer leaflet of either Lipid A or Escherichia coli rough lipopolysaccharides (LPS). The membranes were examined using neutron reflectometry (NR) to examine the coverage and mixing of lipids between the bilayer leaflets. NR data showed that in all cases, the initial deposition asymmetry was mostly maintained for more than 16 h. This stability enabled the sizes of the headgroups and bilayer roughness of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and Lipid A, Rc-LPS and Ra-LPS to be clearly resolved. The results show that rough LPS can be manipulated like phospholipids and used to fabricate advanced asymmetric bacterial membrane models using well-known bilayer deposition techniques. Such models will enable OM dynamics and interactions to be studied under in vivo-like conditions. PMID:24132206

Palmate-like pentafoliata1 encodes a novel Cys(2)His(2) zinc finger transcription factor essential for compound leaf morphogenesis in Medicago truncatula

PubMed Central

2010-01-01

As the primary site for photosynthetic carbon fixation and the interface between plants and the environment, plant leaves play a key role in plant growth, biomass production and survival, and global carbon and oxygen cycles. Leaves can be simple with a single blade or compound with multiple units of blades known as leaflets. In a palmate-type compound leaf, leaflets are clustered at the tip of the leaf. In a pinnate-type compound leaf, on the other hand, leaflets are placed on a rachis in distance from each other. Higher orders of complexities such as bipinnate compound leaves of the “sensitive” plant, Mimosa pudica, also occur in nature. However, how different leaf morphologies are determined is still poorly understood. Medicago truncatula is a model legume closely related to alfalfa and soybean with trifoliate compound leaves. Recently, we have shown that Palmate-like Pentafoliata1 (PALM1) encodes a putative Cys(2) His(2) zinc finger transcription factor essential for compound leaf morphogenesis in M. truncatula. Here, we present our phylogenetic relationship analysis of PALM1 homologs from different species and demonstrate that PALM1 has transcriptional activity in the transactivation assay in yeast. PMID:20724826

Morphological and molecular identification to secure cultivar maintenance and management of self-sterile Rubus arcticus

PubMed Central

Kostamo, K.; Toljamo, A.; Antonius, K.; Kokko, H.; Kärenlampi, S. O.

2013-01-01

Background and Aims Preservation of cultivar purity creates a particular challenge for plants that are self-incompatible, require insects for cross-pollination, and have easily germinating seeds and vigorously spreading rhizomes. As the fields must be planted with mixed populations, and a balance must be maintained between the cultivars to achieve effective pollination, methods for field monitoring of the relative density of different cultivars must be practical. Furthermore, a DNA-based method is needed for cultivar verification in the collections and outside of the growing season. The aim of this study was to develop both types of methods for Rubus arcticus (arctic bramble). Methods Morphological parameters were measured from six cultivars grown on three farms. Observations from the flowers and fruits included: petal and sepal number, flower diameter, arrangement of petals, size of calyx in relation to corolla, fruit weight, yield and soluble sugars. Observations from the leaves included: width and height of middle leaflet, shape of the base of terminal leaflet, shape of terminal leaflet, leaf margin serration and fingertip touch. The applicability of simple sequence repeat (SSR) or microsatellite DNA markers developed for red raspberry was tested on eight arctic bramble cultivars. Key Results and Conclusions Morphological and molecular identification methods were developed for R. arcticus. The best morphological characteristics were the length-to-width ratio of the middle leaflet and leaf margin serration. A particular characteristic, fingertip touch, was shown by electron microscopy to be related to the density and quality of the leaf hairs. Red raspberry SSR marker no. 126 proved to be applicable for differentiation of the eight arctic bramble cultivars tested. These identification methods are critical to secure the maintenance and management of R. arcticus. However, the challenges faced and approaches taken are equally applicable to other species with similar biology. PMID:23456688

Comparison of 3 Different Teaching Methods for a Behavioral Therapy Program for Female Overactive Bladder: A Randomized Controlled Trial.

PubMed

Gezginci, Elif; Iyigun, Emine; Yilmaz, Sercan

The purpose of this study was to compare the effect of 3 instructional methods for behavioral therapy on lower urinary tract symptom (LUTS) severity and health-related quality of life (HRQOL) in women with overactive bladder. Single-center, parallel-group, randomized, clinical trial. The sample comprised 60 women diagnosed with overactive bladder. The study setting was a university-based female urology clinic in Ankara, Turkey; data were collected from November 2012 to May 2013. Eligible participants were ambulatory women 18 years or older with predominant overactive bladder and urge urinary incontinence (UI) symptoms, with or without stress UI symptoms. Subjects were randomized into 4 groups based on educational intervention; group 1 received structured verbal instruction plus a leaflet, group 2 received structured verbal instruction, group 3 received a leaflet alone, and group 4 received usual care that included unstructured verbal counseling about continence care. The primary outcome measures were Incontinence Impact Questionnaire-7 (IIQ-7) and Urinary Distress Inventory-6 (UDI-6) scores. We also measured changes in UI-specific HRQOL scores via the Urinary Incontinence Quality of Life Instrument (I-QOL). All outcomes were measured before and 6 to 8 weeks after the interventions. The Wilcoxon test was used to identify differences in LUTS severity and HRQOL before and after the educational intervention. The Kruskall-Wallis test was used to compare differences among the groups. The severity of LUTS and UI-specific quality of life assessed by the IIQ-7, UDI-6, and I-QOL scores significantly improved after training in all 4 groups (P < .05). The group that received structured verbal instruction plus an educational leaflet achieved significantly lower LUTS scores and significantly higher UI-specific HRQOL when compared to the other groups (P < .05). Findings suggest that structured verbal instruction plus educational leaflet is the most effective method of bladder training in women with overactive bladder and urge UI.

How plant architecture affects light absorption and photosynthesis in tomato: towards an ideotype for plant architecture using a functional–structural plant model

PubMed Central

Sarlikioti, V.; de Visser, P. H. B.; Buck-Sorlin, G. H.; Marcelis, L. F. M.

2011-01-01

Background and Aims Manipulation of plant structure can strongly affect light distribution in the canopy and photosynthesis. The aim of this paper is to find a plant ideotype for optimization of light absorption and canopy photosynthesis. Using a static functional structural plant model (FSPM), a range of different plant architectural characteristics was tested for two different seasons in order to find the optimal architecture with respect to light absorption and photosynthesis. Methods Simulations were performed with an FSPM of a greenhouse-grown tomato crop. Sensitivity analyses were carried out for leaf elevation angle, leaf phyllotaxis, leaflet angle, leaf shape, leaflet arrangement and internode length. From the results of this analysis two possible ideotypes were proposed. Four different vertical light distributions were also tested, while light absorption cumulated over the whole canopy was kept the same. Key Results Photosynthesis was augmented by 6 % in winter and reduced by 7 % in summer, when light absorption in the top part of the canopy was increased by 25 %, while not changing light absorption of the canopy as a whole. The measured plant structure was already optimal with respect to leaf elevation angle, leaflet angle and leaflet arrangement for both light absorption and photosynthesis while phyllotaxis had no effect. Increasing the length : width ratio of leaves by 1·5 or increasing internode length from 7 cm to 12 cm led to an increase of 6–10 % for light absorption and photosynthesis. Conclusions At high light intensities (summer) deeper penetration of light in the canopy improves crop photosynthesis, but not at low light intensities (winter). In particular, internode length and leaf shape affect the vertical distribution of light in the canopy. A new plant ideotype with more spacious canopy architecture due to long internodes and long and narrow leaves led to an increase in crop photosynthesis of up to 10 %. PMID:21865217

Freezing cytorrhysis and critical temperature thresholds for photosystem II in the peat moss Sphagnum capillifolium.

PubMed

Buchner, Othmar; Neuner, Gilbert

2010-07-01

Leaflets of Sphagnum capillifolium were exposed to temperatures from -5 degrees C to +60 degrees C under controlled conditions while mounted on a microscope stage. The resultant cytological response to these temperature treatments was successfully monitored using a light and fluorescence microscope. In addition to the observable cytological changes during freezing cytorrhysis and heat exposure on the leaflets, the concomitant critical temperature thresholds for inactivation of photosystem II (PS II) were studied using a micro fibre optic and a chlorophyll fluorometer mounted to the microscope stage. Chlorophyllous cells of S. capillifolium showed extended freezing cytorrhysis immediately after ice nucleation at -1.1 degrees C in the water in which the leaflets were submersed during the measurement. The occurrence of freezing cytorrhysis, which was visually manifested by cell shrinkage, was highly dynamic and was completed within 2 s. A total reduction of the mean projected diameter of the chloroplast containing area during freezing cytorrhysis from 8.9 to 3.8 microm indicates a cell volume reduction of approximately -82%. Simultaneous measurement of chlorophyll fluorescence of PS II was possible even through the frozen water in which the leaf samples were submersed. Freezing cytorrhysis was accompanied by a sudden rise of basic chlorophyll fluorescence. The critical freezing temperature threshold of PS II was identical to the ice nucleation temperature (-1.1 degrees C). This is significantly above the temperature threshold at which frost damage to S. capillifolium leaflets occurs (-16.1 degrees C; LT(50)) which is higher than observed in most higher plants from the European Alps during summer. High temperature thresholds of PS II were 44.5 degrees C which is significantly below the heat tolerance of chlorophyllous cells (49.9 degrees C; LT(50)). It is demonstrated that light and fluorescence microscopic techniques combined with simultaneous chlorophyll fluorescence measurements may act as a useful tool to study heat, low temperature, and ice-encasement effects on the cellular structure and primary photosynthetic processes of intact leaf tissues.

Usefulness of Tricuspid Annular Diameter to Predict Late Right Sided Heart Failure in Patients With Left Ventricular Assist Device.

PubMed

Nakanishi, Koki; Homma, Shunichi; Han, Jiho; Takayama, Hiroo; Colombo, Paolo C; Yuzefpolskaya, Melana; Garan, Arthur R; Farr, Maryjane A; Kurlansky, Paul; Di Tullio, Marco R; Naka, Yoshifumi; Takeda, Koji

2018-07-01

Although late-onset right-sided heart failure is recognized as a clinical problem in the treatment of patients with left ventricular assist devices (LVADs), the mechanism and predictors are unknown. Tricuspid valve (TV) deformation leads to the restriction of the leaflet motion and decreased coaptation, resulting in a functional tricuspid regurgitation that may act as a surrogate marker of late right-sided heart failure. This study aimed to investigate the association of preoperative TV deformation (annulus dilatation and leaflet tethering) with late right-sided heart failure development after continuous-flow LVAD implantation. The study cohort consisted of 274 patients who underwent 2-dimensional echocardiography before LVAD implantation. TV annulus diameter and tethering distance were measured in an apical 4-chamber view. Late right-sided heart failure was defined as right-sided heart failure requiring readmission and medical and/or surgical treatment after initial LVAD implantation. During a mean follow-up of 25.1 ± 19.0 months after LVAD implantation, late right-sided heart failure occurred in 33 patients (12.0%). Multivariate Cox proportional hazard analysis demonstrated that TV annulus diameter (hazard ratio 1.221 per 1 mm, p <0.001) was significantly associated with late right-sided heart failure development, whereas leaflet tethering distance was not. The best cut-off value of the TV annular diameter was 41 mm (area under the curve 0.787). Kaplan-Meier analysis showed that patients with dilated TV annulus (TV annular diameter ≥41 mm) exhibited a significantly higher late right-sided heart failure occurrence than those without TV annular enlargement (log-rank p <0.001). In conclusion, preoperative TV annulus diameter, but not leaflet tethering distance, predicted the occurrence of late right-sided heart failure after LVAD implantation. Copyright © 2018 Elsevier Inc. All rights reserved.

Preconceptions influence women's perceptions of information on breast cancer screening: a qualitative study.

PubMed

Henriksen, Mikael Johannes Vuokko; Guassora, Ann Dorrit; Brodersen, John

2015-09-03

Screening for breast cancer has been subject to intense debate in recent decades regarding benefits and risks. Participation in breast cancer screening should be based on informed choice, and most countries approach this by sending information leaflets with invitations to attend screening. However, very little attention has been paid to the decision-making process and how the information leaflets are used and understood by women. The aim of this study is twofold. First, we use a theoretical framework to explore how the framing of information influences the intention to participate in breast cancer screening. Second, we discuss how information and attitudes held prior to receiving the invitation influence the perception of the balance between the benefits and risks harms of screening. We used a qualitative design and interviewed six women who were soon to receive their first invitation to participate in the breast screening programme in Denmark. The selected women received a copy of the official information leaflet 1 week before we interviewed them. The six women were interviewed individually using an interview guide based on the theory of planned behaviour. We used meaning condensation for our initial analysis, and further analysis was guided by the theory of cognitive dissonance. For our participants, the decision-making process was dominated by the attitudes of the women's circle of acquaintances and, to a lesser extent, by the information that accompanied the screening invitation. Information that conflicted with attitudes the women already held was actively disregarded. The risk of overdiagnosis as a potentially harmful effect of participation in mammography screening was unknown to the women in our study. An isolated framing effect was not found. Women have expectations about breast cancer screening that are formed before they receive information from the screening programme. These expectations compromise the perception of balance between screening benefits and potential harmful effects. They also influence the perception of the information in the breast screening leaflet. The phenomenon of overdiagnosis is unknown to the women.

Finite Element Analysis of Patient-Specific Mitral Valve with Mitral Regurgitation.

PubMed

Pham, Thuy; Kong, Fanwei; Martin, Caitlin; Wang, Qian; Primiano, Charles; McKay, Raymond; Elefteriades, John; Sun, Wei

2017-03-01

Functional mitral regurgitation (FMR) is a significant complication of left ventricular dysfunction and strongly associated with a poor prognosis. In this study, we developed a patient-specific finite element (FE) model of the mitral apparatus in a FMR patient which included: both leaflets with thickness, annulus, chordae tendineae, and chordae insertions on the leaflets and origins on the papillary muscles. The FE model incorporated human age- and gender-matched anisotropic hyperelastic material properties, and MV closure at systole was simulated. The model was validated by comparing the FE results from valve closure simulation with the in vivo geometry of the MV at systole. It was found that the FE model could not replicate the in vivo MV geometry without the application of tethering pre-tension force in the chordae at diastole. Upon applying the pre-tension force and performing model optimization by adjusting the chordal length, position, and leaflet length, a good agreement between the FE model and the in vivo model was established. Not only were the chordal forces high at both diastole and systole, but the tethering force on the anterior papillary muscle was higher than that of the posterior papillary muscle, which resulted in an asymmetrical gap with a larger orifice area at the anterolateral commissure resulting in MR. The analyses further show that high peak stress and strain were found at the chordal insertions where large chordal tethering forces were found. This study shows that the pre-tension tethering force plays an important role in accurately simulating the MV dynamics in this FMR patient, particularly in quantifying the degree of leaflet coaptation and stress distribution. Due to the complexity of the disease, the patient-specific computational modeling procedure of FMR patients presented should be further evaluated using a large patient cohort. However, this study provides useful insights into the MV biomechanics of a FMR patient, and could serve as a tool to assist in pre-operative planning for MV repair or replacement surgical or interventional procedures.

FLUID-STRUCTURE INTERACTION MODELS OF THE MITRAL VALVE: FUNCTION IN NORMAL AND PATHOLOGIC STATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunzelman, K. S.; Einstein, Daniel R.; Cochran, R. P.

2007-08-29

Successful mitral valve repair is dependent upon a full understanding of normal and abnormal mitral valve anatomy and function. Computational analysis is one such method that can be applied to simulate mitral valve function in order to analyze the roles of individual components, and evaluate proposed surgical repair. We developed the first three-dimensional, finite element (FE) computer model of the mitral valve including leaflets and chordae tendineae, however, one critical aspect that has been missing until the last few years was the evaluation of fluid flow, as coupled to the function of the mitral valve structure. We present here ourmore » latest results for normal function and specific pathologic changes using a fluid-structure interaction (FSI) model. Normal valve function was first assessed, followed by pathologic material changes in collagen fiber volume fraction, fiber stiffness, fiber splay, and isotropic stiffness. Leaflet and chordal stress and strain, and papillary muscle force was determined. In addition, transmitral flow, time to leaflet closure, and heart valve sound were assessed. Model predictions in the normal state agreed well with a wide range of available in-vivo and in-vitro data. Further, pathologic material changes that preserved the anisotropy of the valve leaflets were found to preserve valve function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valve function. The addition of blood flow and an experimentally driven microstructural description of mitral tissue represent significant advances in computational studies of the mitral valve, which allow further insight to be gained. This work is another building block in the foundation of a computational framework to aid in the refinement and development of a truly noninvasive diagnostic evaluation of the mitral valve. Ultimately, it represents the basis for simulation of surgical repair of pathologic valves in a clinical and educational setting.« less

Cracking the omega code: hydraulic architecture of the cycad leaf axis.

PubMed

Tomlinson, P Barry; Ricciardi, Alison; Huggett, Brett A

2018-03-05

The leaf axis of members of the order Cycadales ('cycads') has long been recognized by its configuration of independent vascular bundles that, in transverse section, resemble the Greek letter omega (hence the 'omega pattern'). This provides a useful diagnostic character for the order, especially when applied to paleobotany. The function of this pattern has never been elucidated. Here we provide a three-dimensional analysis and explain the pattern in terms of the hydraulic architecture of the pinnately compound cycad leaf. The genus Cycas was used as a simple model, because each leaflet is supplied by a single vascular bundle. Sequential sectioning was conducted throughout the leaf axis and photographed with a digital camera. Photographs were registered and converted to a cinematic format, which provided an objective method of analysis. The omega pattern in the petiole can be sub-divided into three vascular components, an abaxial 'circle', a central 'column' and two adaxial 'wings', the last being the only direct source of vascular supply to the leaflets. Each leaflet is supplied by a vascular bundle that has divided or migrated directly from the closest wing bundle. There is neither multiplication nor anastomoses of vascular bundles in the other two components. Thus, as one proceeds from base to apex along the leaf axis, the number of vascular bundles in circle and column components is reduced distally by their uniform migration throughout all components. Consequently, the distal leaflets are irrigated by the more abaxial bundles, guaranteeing uniform water supply along the length of the axis. The omega pattern exemplifies one of the many solutions plants have achieved in supplying distal appendages of an axis with a uniform water supply. Our method presents a model that can be applied to other genera of cycads with more complex vascular organization. © The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Functional and Biomechanical Effects of the Edge-to-Edge Repair in the Setting of Mitral Regurgitation: Consolidated Knowledge and Novel Tools to Gain Insight into Its Percutaneous Implementation.

PubMed

Sturla, Francesco; Redaelli, Alberto; Puppini, Giovanni; Onorati, Francesco; Faggian, Giuseppe; Votta, Emiliano

2015-06-01

Mitral regurgitation is the most prevalent heart valve disease in the western population. When severe, it requires surgical treatment, repair being the preferred option. The edge-to-edge repair technique treats mitral regurgitation by suturing the leaflets together and creating a double-orifice valve. Due to its relative simplicity and versatility, it has become progressively more widespread. Recently, its percutaneous version has become feasible, and has raised interest thanks to the positive results of the Mitraclip(®) device. Edge-to-edge features and evolution have stimulated debate and multidisciplinary research by both clinicians and engineers. After providing an overview of representative studies in the field, here we propose a novel computational approach to the most recent percutaneous evolution of the edge-to-edge technique. Image-based structural finite element models of three mitral valves affected by posterior prolapse were derived from cine-cardiac magnetic resonance imaging. The models accounted for the patient-specific 3D geometry of the valve, including leaflet compound curvature pattern, patient-specific motion of annulus and papillary muscles, and hyperelastic and anisotropic mechanical properties of tissues. The biomechanics of the three valves throughout the entire cardiac cycle was simulated before and after Mitraclip(®) implantation, assessing the biomechanical impact of the procedure. For all three simulated MVs, Mitraclip(®) implantation significantly improved systolic leaflets coaptation, without inducing major alterations in systolic peak stresses. Diastolic orifice area was decreased, by up to 58.9%, and leaflets diastolic stresses became comparable, although lower, to systolic ones. Despite established knowledge on the edge-to-edge surgical repair, latest technological advances make its percutanoues implementation a challenging field of research. The modeling approach herein proposed may be expanded to analyze clinical scenarios that are currently critical for Mitraclip(®) implantation, helping the search for possible solutions.

Recycling of dolichyl monophosphate to the cytoplasmic leaflet of the endoplasmic reticulum after the cleavage of dolichyl pyrophosphate on the lumenal monolayer.

PubMed

Rush, Jeffrey S; Gao, Ningguo; Lehrman, Mark A; Waechter, Charles J

2008-02-15

During protein N-glycosylation, dolichyl pyrophosphate (Dol-P-P) is discharged in the lumenal monolayer of the endoplasmic reticulum (ER). Dol-P-P is then cleaved to Dol-P by Dol-P-P phosphatase (DPPase). Studies with the yeast mutant cwh8Delta, lacking DPPase activity, indicate that recycling of Dol-P produced by DPPase contributes significantly to the pool of Dol-P utilized for lipid intermediate biosynthesis on the cytoplasmic leaflet. Whether Dol-P formed in the lumen diffuses directly back to the cytoplasmic leaflet or is first dephosphorylated to dolichol has not been determined. Incubation of sealed ER vesicles from calf brain with acetyl-Asn-Tyr-Thr-NH(2), an N-glycosylatable peptide, to generate Dol-P-P in the lumenal monolayer produced corresponding increases in the rates of Man-P-Dol, Glc-P-Dol, and GlcNAc-P-P-Dol synthesis in the absence of CTP. No changes in dolichol kinase activity were observed. When streptolysin-O permeabilized CHO cells were incubated with an acceptor peptide, N-glycopeptide synthesis, requiring multiple cycles of the dolichol pathway, occurred in the absence of CTP. The results obtained with sealed microsomes and CHO cells indicate that Dol-P, formed from Dol-P-P, returns to the cytoplasmic leaflet where it can be reutilized for lipid intermediate biosynthesis, and dolichol kinase is not required for recycling. It is possible that the flip-flopping of the carrier lipid is mediated by a flippase, which would provide a mechanism for the recycling of Dol-P derived from Man-P-Dol-mediated reactions in N-, O-, and C-mannosylation of proteins, GPI anchor assembly, and the three Glc-P-Dol-mediated reactions in Glc(3)Man(9)GlcNAc(2)-P-P-Dol (DLO) biosynthesis.

Differentiation of thrombus from pannus as the cause of acquired mechanical prosthetic heart valve obstruction by non-invasive imaging: a review of the literature.

PubMed

Tanis, Wilco; Habets, Jesse; van den Brink, Renee B A; Symersky, Petr; Budde, Ricardo P J; Chamuleau, Steven A J

2014-02-01

For acquired mechanical prosthetic heart valve (PHV) obstruction and suspicion on thrombosis, recently updated European Society of Cardiology guidelines advocate the confirmation of thrombus by transthoracic echocardiography, transesophageal echocardiography (TEE), and fluoroscopy. However, no evidence-based diagnostic algorithm is available for correct thrombus detection, although this is clinically important as fibrinolysis is contraindicated in non-thrombotic obstruction (isolated pannus). Here, we performed a review of the literature in order to propose a diagnostic algorithm. We performed a systematic search in Pubmed and Embase. Included publications were assessed on methodological quality based on the validated Quality Assessment of Diagnostic Accuracy Studies (QUADAS) II checklist. Studies were scarce (n = 15) and the majority were of moderate methodological quality. In total, 238 mechanical PHV's with acquired obstruction and a reliable reference standard were included for the evaluation of the role of fluoroscopy, echocardiography, or multidetector-row computed tomography (MDCT). In acquired PHV obstruction caused by thrombosis, mass detection by TEE and leaflet restriction detected by fluoroscopy were observed in the majority of cases (96 and 100%, respectively). In contrast, in acquired PHV obstruction free of thrombosis (pannus), leaflet restriction detected by fluoroscopy was absent in some cases (17%) and mass detection by TEE was absent in the majority of cases (66%). In case of mass detection by TEE, predictors for obstructive thrombus masses (compared with pannus masses) were leaflet restriction, soft echo density, and increased mass length. In situations of inconclusive echocardiography, MDCT may correctly detect pannus/thrombus based on the morphological aspects and localization. In acquired mechanical PHV obstruction without leaflet restriction and absent mass on TEE, obstructive PHV thrombosis cannot be confirmed and consequently, fibrinolysis is not advised. Based on the literature search and our opinion, a diagnostic algorithm is provided to correctly identify non-thrombotic PHV obstruction, which is highly relevant in daily clinical practice.

How plant architecture affects light absorption and photosynthesis in tomato: towards an ideotype for plant architecture using a functional-structural plant model.

PubMed

Sarlikioti, V; de Visser, P H B; Buck-Sorlin, G H; Marcelis, L F M

2011-10-01

Manipulation of plant structure can strongly affect light distribution in the canopy and photosynthesis. The aim of this paper is to find a plant ideotype for optimization of light absorption and canopy photosynthesis. Using a static functional structural plant model (FSPM), a range of different plant architectural characteristics was tested for two different seasons in order to find the optimal architecture with respect to light absorption and photosynthesis. Simulations were performed with an FSPM of a greenhouse-grown tomato crop. Sensitivity analyses were carried out for leaf elevation angle, leaf phyllotaxis, leaflet angle, leaf shape, leaflet arrangement and internode length. From the results of this analysis two possible ideotypes were proposed. Four different vertical light distributions were also tested, while light absorption cumulated over the whole canopy was kept the same. Photosynthesis was augmented by 6 % in winter and reduced by 7 % in summer, when light absorption in the top part of the canopy was increased by 25 %, while not changing light absorption of the canopy as a whole. The measured plant structure was already optimal with respect to leaf elevation angle, leaflet angle and leaflet arrangement for both light absorption and photosynthesis while phyllotaxis had no effect. Increasing the length : width ratio of leaves by 1·5 or increasing internode length from 7 cm to 12 cm led to an increase of 6-10 % for light absorption and photosynthesis. At high light intensities (summer) deeper penetration of light in the canopy improves crop photosynthesis, but not at low light intensities (winter). In particular, internode length and leaf shape affect the vertical distribution of light in the canopy. A new plant ideotype with more spacious canopy architecture due to long internodes and long and narrow leaves led to an increase in crop photosynthesis of up to 10 %.

A second prosthesis as a procedural rescue option in trans-apical aortic valve implantation.

PubMed

Kempfert, Jörg; Rastan, Ardawan J; Schuler, Gerhard; Linke, Axel; Holzhey, David; van Linden, Arnaud; Mohr, Friedrich-W; Walther, Thomas

2011-07-01

Trans-apical aortic valve implantation (TA-AVI) using the Edwards SAPIEN™ prosthesis has evolved to a routine procedure for selected high-risk elderly patients. In rare cases, misplacement of the SAPIEN™ valve (too low a position), dysfunction of the leaflets or perforation of the interventricular septum (ventricular septal defect, VSD) occurs and requires immediate implantation of a second prosthesis within the first one. Results of this 'bailout' maneuver have not been reported yet. Of 305 TA-AVI procedures, 15 patients required a second prosthesis due to dysfunctional leaflets (n = 6), low position (n = 7), or VSD (n = 2). Mean age was 82.5 ± 1.3 years, mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 45.5 ± 5.4, and Society of Thoracic Surgeons (STS) Score was 13.5 ± 1.5. All second SAPIEN™ valves could be implanted successfully within the first one. The second prosthesis solved leaflet dysfunction, sealed the VSD (lower position of the second prosthesis), or corrected the initial misplacement (higher position of the second prosthesis) in all patients. Within 30 days, four patients died (low cardiac output n = 3, all with preoperative ejection fraction (EF) <35%; intestinal ischemia n = 1). Intra-operative echocardiogram and angiogram revealed mild paravalvular leak in three and none/trace in 12 patients. Transvalvular gradients were low despite the implantation of the second valve (P(max)/mean 13.7 ± 4.3/6.4 ± 2.0). Placement of a second SAPIEN™ valve is a valuable 'bailout' technique in case of VSD, dysfunctional leaflets, or too low placement of the first prosthesis. The technique leads to an excellent functional result with low transvalvular gradients. The simple, straight, tubular stent design of the SAPIEN™ prosthesis may be the ideal design for such valve-in-valve procedures. Copyright © 2011 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Vector flow mapping in obstructive hypertrophic cardiomyopathy to assess the relationship of early systolic left ventricular flow and the mitral valve.

PubMed

Ro, Richard; Halpern, Dan; Sahn, David J; Homel, Peter; Arabadjian, Milla; Lopresto, Charles; Sherrid, Mark V

2014-11-11

The hydrodynamic cause of systolic anterior motion of the mitral valve (SAM) is unresolved. This study hypothesized that echocardiographic vector flow mapping, a new echocardiographic technique, would provide insights into the cause of early SAM in obstructive hypertrophic cardiomyopathy (HCM). We analyzed the spatial relationship of left ventricular (LV) flow and the mitral valve leaflets (MVL) on 3-chamber vector flow mapping frames, and performed mitral valve measurements on 2-dimensional frames in patients with obstructive and nonobstructive HCM and in normal patients. We compared 82 patients (22 obstructive HCM, 23 nonobstructive HCM, and 37 normal) by measuring 164 LV pre- and post-SAM velocity vector flow maps, 82 maximum isovolumic vortices, and 328 2-dimensional frames. We observed color flow and velocity vector flow posterior to the MVL impacting them in the early systolic frames of 95% of obstructive HCM, 22% of nonobstructive HCM, and 11% of normal patients (p < 0.001). In both pre- and post-SAM frames, we measured a high angle of attack >60° of local vector flow onto the posterior surface of the leaflets whether the flow was ejection (59%) or the early systolic isovolumic vortex (41%). Ricochet of vector flow, rebounding off the leaflet into the cul-de-sac, was noted in 82% of the obstructed HCM, 9% of nonobstructive HCM, and none (0%) of the control patients (p < 0.001). Flow velocities in the LV outflow tract on the pre-SAM frame 1 and 2 mm from the tip of the anterior leaflet were low: 39 and 43 cm/s, respectively. Early systolic flow impacts the posterior surfaces of protruding MVL initiating SAM in obstructive HCM. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Randomised comparison of three tools for improving compliance with occlusion therapy: an educational cartoon story, a reward calendar, and an information leaflet for parents.

PubMed

Tjiam, A M; Holtslag, G; Van Minderhout, H M; Simonsz-Tóth, B; Vermeulen-Jong, M H L; Borsboom, G J J M; Loudon, S E; Simonsz, H J

2013-01-01

We previously demonstrated that compliance with occlusion therapy for amblyopia was improved by the use of an educational programme, especially in children of parents of foreign origin and who spoke Dutch poorly. The programme consisted of: (i) a cartoon story for amblyopic children that explained without words why they should patch, (ii) a calendar with reward stickers, and (iii) an information leaflet for parents. In the current study, we assessed the individual effect of each component on compliance. We recruited 120 3- to 6-year-old children who lived in a low socio-economic status (SES) area in The Hague and were starting occlusion therapy for the first time. They were randomised to receive one of the components (three intervention groups), or a picture to colour (control group). The randomisation was blinded for treating orthoptist and researcher. Compliance was measured electronically using the Occlusion Dose Monitor (ODM). Primary outcome was percentage of compliance (actual/prescribed occlusion time). Secondary outcome was absolute occlusion hours per day. Parental fluency in Dutch was rated on a five-point scale. Compliance could be measured electronically in 88 of the 120 children; in 32 others, it failed for various reasons. Parental fluency in Dutch was moderate or worse in 36.4 % (p = 0.327). Average compliance was 55 % standard deviation (SD) 40 (n = 18) in the control group, 89 % SD 25 in the group receiving the educational cartoon (n = 25, P = 0.002 compared with control group), 67 % SD 33 (n = 24, P = 0.301) in the reward-calendar group and 73 % SD 40 (n = 21, P = 0.119) in the parent-information-leaflet group. On average, children in the control group occluded 1:46 SD1:19 hours/day, 2:33 SD 1:18 hours/day in the group receiving the educational cartoon, 1:59 SD 1:13 hours/day in the reward-calendar group and 2:18 SD 1:13 hours/day in the parent-information-leaflet group. No child who received the cartoon story occluded less than 1 hour per day, against seven in the reward-calendar group, five in the parent-information-leaflet group and five in the control group. Although all three components of the programme improved compliance with occlusion therapy in children in low-SES areas, the educational cartoon had the strongest effect, as it explained without words to a 4- to 5-year-old child why it should wear the eye patch.

The Escherichia coli Phospholipase PldA Regulates Outer Membrane Homeostasis via Lipid Signaling.

PubMed

May, Kerrie L; Silhavy, Thomas J

2018-03-20

The outer membrane (OM) bilayer of Gram-negative bacteria is biologically unique in its asymmetrical organization of lipids, with an inner leaflet composed of glycerophospholipids (PLs) and a surface-exposed outer leaflet composed of lipopolysaccharide (LPS). This lipid organization is integral to the OM's barrier properties. Perturbations of the outer leaflet by antimicrobial peptides or defects in LPS biosynthesis or transport to the OM cause a compensatory flipping of PLs to the outer leaflet. As a result, lipid asymmetry is disrupted and OM integrity is compromised. Recently, we identified an Escherichia coli mutant that exhibits aberrant accumulation of surface PLs accompanied by a cellular increase in LPS production. Remarkably, the observed hyperproduction of LPS is PldA dependent. Here we provide evidence that the fatty acids generated by PldA at the OM are transported into the cytoplasm and simultaneously activated by thioesterification to coenzyme A (CoA) by FadD. The acyl-CoAs produced ultimately inhibit LpxC degradation by FtsH. The increased levels of LpxC, the enzyme that catalyzes the first committed step in LPS biosynthesis, increases the amount of LPS produced. Our data suggest that PldA acts as a sensor for lipid asymmetry in the OM. PldA protects the OM barrier by both degrading mislocalized PLs and generating lipid second messengers that enable long-distance signaling that prompts the cell to restore homeostasis at a distant organelle. IMPORTANCE The outer membrane of Gram-negative bacteria is an effective permeability barrier that protects the cell from toxic agents, including antibiotics. Barrier defects are often manifested by phospholipids present in the outer leaflet of this membrane that take up space normally occupied by lipopolysaccharide. We have discovered a signaling mechanism that operates across the entire cell envelope used by the cell to detect these outer membrane defects. A phospholipase, PldA, that functions to degrade these mislocalized phospholipids has a second, equally important function as a sensor. The fatty acids produced by hydrolysis of the phospholipids act as second messengers to signal the cell that more lipopolysaccharide is needed. These fatty acids diffuse across the periplasm and are transported into the cytoplasm by a process that attaches coenzyme A. The acyl-CoA molecule produces signals to inhibit the degradation of the critical enzyme LpxC by the ATP-dependent protease FtsH, increasing lipopolysaccharide production. Copyright © 2018 May and Silhavy.

Creation and Relaxation of Phospholipid Compositional Asymmetry in Lipid Bilayers Examined by Sum-Frequency Vibrational Spectroscopy

NASA Astrophysics Data System (ADS)

Anglin, Timothy C.; Brown, Krystal; Conboy, John C.

2010-08-01

Eukaryotic cells contain an asymmetric distribution of phospholipids in the two leaflets of the lipid bilayer which is known to contribute to cellular function. In the plasma membrane of eukaryotic cells, the aminophospholipids with phosphatidylserine (PS) and phosphatidylethanolamine (PE) headgroups are predominately located on the cytosolic leaflet while sphingolipids with phosphatidylcholine (PC) headgroups and sphingomeylin are on the extra-cellular leaflet. There have been a number of theories about the mechanism of transbilayer movement of lipids in cellular systems and the physical process by which lipid compositional asymmetry in the plasma membrane of eukaryotic cells is maintained. It is generally accepted that a significant barrier to native lipid translocation (movement between leaflets of the bilayer) exists which is related to the energetic penalty of moving the hydrophilic headgroup of a phospholipid through the hydrophobic core of the membrane. Overcoming this energetic barrier represents the rate limiting step in the spontaneous flip-flop of phospholipids in biological membranes, yet, while numerous kinetic studies of phospholipid flip-flop have been conducted, few researchers have reported thermodynamic parameters for the process. Using methods of classical surface chemistry coupled with nonlinear optical methods, we have developed a novel analytical approach, using sum-frequency vibrational spectroscopy (SFVS), to selectively probe lipid compositional asymmetry in a planar supported lipid bilayer. This new method allows for the detection of lipid flip-flop kinetics and compositional asymmetry without the need for a fluorescent or spin-labeled lipid species by exploiting the coherent nature of SFVS. The SFVS intensity arising from the terminal methyl groups of the lipid fatty acid chains is used as an internal probe to directly monitor the compositional asymmetry in planar supported lipid bilayers (PSLBs(. By selectively deuterating a sub-population of lipids, the SFVS intensity is proportional to the population difference between hydrogenated lipids in the top, NT, and the bottom, NB, leaflets due to the cancellation of the SFVS signal arising from lipids hydrogenated residing in an anti-parallel arrangement, allowing us to directly relate the measured intensity to the population difference in the bilayer (Equation 1) and provides a direct measure of the percent asymmetry (%AS) in the membrane (Equation 2). ICH3∝(NT-NB)2 (1) %AS = (NT-NB)/NTotal×100 (2) In this presentation, the effect of lipid composition, headgroup and fatty acid chemical structure, on the rate and thermodynamics of lipid transbilayer migration and the electrostatic induction of lipid asymmetry will be discussed.

Surgical treatment of functional ischemic mitral regurgitation.

PubMed

Jensen, Henrik

2015-03-01

In many ways we are at a crossroad in terms of what constitutes optimal FIMR treatment: is CABG combined with mitral valve ring annuloplasty better than CABG alone in moderate FIMR? Is mitral valve repair really better than replacement? And does adding a valvular repair or subvalvular reverse remodeling procedure shift that balance? In the present thesis I aim to shed further light on these questions by addressing the current status and future perspectives of the surgical treatment of FIMR. CURRENT SURGICAL TREATMENT FOR FIMR. CABG alone: The overall impression from the literature is that patients are left with a high grade of persistent/recurrent FIMR from isolated CABG. CABG is most effective to treat FIMR in patients with viable myocardium (at least five viable segments) and absence of dyssynchrony between papillary muscles (< 60 ms). Mitral valve ring annuloplasty. A vast number of different designs are available to perform mitral valve ring annuloplasty with variations over the theme of complete/partial and rigid/semi-rigid/flexible. Also, the three-dimensional shape of the rigid and semi-rigid rings is the subject of great variation. A rigid or semi-rigid down-sized mitral valve ring annuloplasty is the most advocated treatment in chronic FIMR grade 2+ or higher. Combined CABG and mitral valve ring annuloplasty: CABG combined with mitral valve ring annuloplasty leads to reverse LV remodeling and reduced volumes. Despite this, the recurrence rate after combined CABG and mitral valve ring annuloplasty is 20-30% at 2-4 years follow-up. This is also true for studies strictly using down-sized mitral valve ring annuloplasty by two sizes. A number of preoperative risk factors to develop recurrent FIMR were identified, e.g. LVEDD > 65-70 mm, coaptation depth > 10 mm, anterior leaflet angle > 27-39.5°, posterior leaflet angle > 45° and interpapillary muscle distance > 20 mm. CABG alone vs. combined CABG and mitral valve ring annuloplasty: The current available literature, including three randomized studies and a meta analysis, indicate that combined CABG and mitral valve ring annuloplasty has no late survival difference compared with CABG alone, and early mortality might even be higher. Meanwhile, adding a mitral valve ring annuloplasty results in a lower NYHA functional class, most likely as a consequence of a lower incidence of persistent or recurrent FIMR. More randomized studies are being conducted to further address this topic. Mitral valve ring annuloplasty vs. mitral valve replacement. The early survival may be higher after repair compared with replacement, meanwhile, the literature is more ambiguous in terms of late survival advantages, and recent reports find no late survival advantage from repair over replacement. The recurrence rates after ring annuloplasty addressed above were also present in this subset of patients, whereas the incidence of recurrent FIMR after valve replacement is scarcely reported. There was an overall tendency of slightly higher incidence of reoperations after ring annuloplasty. The mitral valve annulus: Innovations in mitral valve ring annuloplasty: The latest innovation in mitral valve ring annuloplasty design includes adjustable rings, allowing adjustment of septo-lateral dimensions intra- or postoperatively. Minimally invasive ring annuloplasty using indirect coronary sinus devices, has been introduced, but so far have produced suboptimal results in terms of safety and efficacy. Also, first in man testing of direct percutaneous catheter based mitral annuloplasty techniques have been conducted. Leaflets and chordae: Direct repair techniques: Surgical methods have been developed to directly address the mitral valve leaflets and chordae tendineae to correct leaflet tethering in FIMR. Both the Alfieri stich and the minimally invasive MitraClip attaches the anterior and posterior leaflets, typically the A2-P2 region, to correct incomplete leaflet coaptation. Patch augmentation of the posterior leaflet in the P2-P3 region increases coaptation in the area most prone to cause FIMR. Chordal cutting of the secondary "strut" chordae releases the anterior leaflet from the tethering due to papillary muscle displacement and improves mitral valve geometry. The mitral subvalvular apparatus: Numerous subvalvular approaches to improve outcome in patients with FIMR have been introduced. They include very invasive techniques such as surgical ventricular restoration procedure, surgical techniques directly addressing the papillary muscle dis-placement, and beating heart procedures using transventricular and epicardial devices applied in a few minutes. The role of the transventricular and epicardial devices still remains to be defined and many of these devices seem to have a hard time ganing their footing in the clinical practise and until now only constitute a footnote in the surgical literature. Meanwhile, the current results with adjunct techniques to CABG and ring annuloplasty, such as the papillary muscle approximation technique introduced by Hvass et al and the papillary muscle relocation technique introduced by Kron et al and further developed by Langer et al are gaining continuing support in the surgical community since these techniques can be used with only little added time consumption but with very good clinical outcome.

12 CFR 1014.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., leaflet, circular, mailer, book insert, free standing insert, letter, catalogue, poster, chart, billboard... firms, program-length commercial (“infomercial”), the internet, cellular network, or any other medium...

12 CFR 1014.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., leaflet, circular, mailer, book insert, free standing insert, letter, catalogue, poster, chart, billboard... firms, program-length commercial (“infomercial”), the internet, cellular network, or any other medium...

12 CFR 1014.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., leaflet, circular, mailer, book insert, free standing insert, letter, catalogue, poster, chart, billboard... firms, program-length commercial (“infomercial”), the internet, cellular network, or any other medium...

Severe tricuspid regurgitation due to entrapment of the anterior leaflet of the valve by a permanent pacemaker lead: role of real time three-dimensional echocardiography.

PubMed

Nucifora, Gaetano; Badano, Luigi P; Allocca, Giuseppe; Gianfagna, Pasquale; Proclemer, Alessandro; Cinello, Margherita; Fioretti, Paolo M

2007-07-01

Pacemaker leads may impair tricuspid valve coaptation and they are a well-known cause of mild tricuspid regurgitation. Occasionally, right ventricular leads worsen tricuspid regurgitation over time and patients develop late-onset symptoms of right-sided heart failure. The exact mechanism of this clinical entity is rarely identifiable by 2D-echocardiography only. This case report details a patient with severe tricuspid regurgitation secondary to immobilization of the anterior leaflet of the tricuspid valve by a permanent ventricular pacing lead. The mechanism of regurgitation was clarified by real time three-dimensional echocardiography that showed the location of the ventricular lead and its interference with the tricuspid valve.

Congenital absence of pulmonary valve leaflets.

PubMed Central

Buendia, A; Attie, F; Ovseyevitz, J; Zghaib, A; Zamora, C; Zavaleta, D; Vargas-Barron, J; Richheimer, R

1983-01-01

Congenital absence of pulmonary valve leaflets is an uncommon condition usually associated with ventricular septal defect and an obstructive pulmonary valve ring. Twenty-one patients with these malformations are described. Twenty had an associated ventricular septal defect with ventriculoarterial concordance, and one also had transposition of the great arteries, ventricular septal defect, and obstructive pulmonary valve ring. The clinical features, cardiac catheterisation findings, and angiocardiographic results are presented. Twelve patients underwent cardiac surgery. Three patients died, one in the early, and the other two in the late postoperative period. The results, according to the surgical technique employed and postoperative cardiac catheterisation findings, showed that patients in whom the bioprostheses were implanted in the pulmonary position had a better late follow-up. Images PMID:6860509

The complex that inserts lipopolysaccharide into the bacterial outer membrane forms a two-protein plug-and-barrel.

PubMed

Freinkman, Elizaveta; Chng, Shu-Sin; Kahne, Daniel

2011-02-08

The cell surfaces of Gram-negative bacteria are composed of lipopolysaccharide (LPS). This glycolipid is found exclusively in the outer leaflet of the asymmetric outer membrane (OM), where it forms a barrier to the entry of toxic hydrophobic molecules into the cell. LPS typically contains six fatty acyl chains and up to several hundred sugar residues. It is biosynthesized in the cytosol and must then be transported across two membranes and an aqueous intermembrane space to the cell surface. These processes are required for the viability of most Gram-negative organisms. The integral membrane β-barrel LptD and the lipoprotein LptE form an essential complex in the OM, which is necessary for LPS assembly. It is not known how this complex translocates large, amphipathic LPS molecules across the OM to the outer leaflet. Here, we show that LptE resides within the LptD β-barrel both in vitro and in vivo. LptD/E associate via an extensive interface; in one specific interaction, LptE contacts a predicted extracellular loop of LptD through the lumen of the β-barrel. Disrupting this interaction site compromises the biogenesis of LptD. This unprecedented two-protein plug-and-barrel architecture suggests how LptD/E can insert LPS from the periplasm directly into the outer leaflet of the OM to establish the asymmetry of the bilayer.

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

PubMed

Hunt, William T N; McGrath, Emily J

2016-06-01

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

Analysis of hydrodynamic losses for various types of aortic valves

NASA Astrophysics Data System (ADS)

Starobin, I. M.; Lupachev, S. P.; Dolgopolov, R. V.; Zaiko, V. M.; Kas'yanov, V. A.; Mungalov, D. D.; Morov, G. V.

1985-05-01

The creation of an automated computer-controlled hydraulic stand made it possible to measure the main hydrodynamic parameters of the flow through the investigated HVP and to determine the coefficients of Eq. (2) of fluid flow in the test chamber of the stand. The coefficients found can serve as a criterion of a comparative assessment of the hydrodynamics of HVPs. An analysis of the coefficients showed that the main contribution to pressure losses across ball and disc valves is made by viscous and convective effects. An analysis of inertial losses confirmed the presence of oscillations of the ball closing elements of the AKCh-3-06 valve around the props of the stroke limiters and made it possible to assess them quantitatively. For leaflet valves the contribution of inertial losses to the total pressure losses is more considerable than in the case of disc and ball valves both in the regime of an increase of power of the output and in the regime of a constant power. The mechanical properties of the material of leaflet valves have an effect on the hydrodynamic characteristics. The advantage of the investigated leaflet valves consists not only in that they have smaller total hydraulic losses compared with the other valves, but also in that they provide a high amplitude of pulsations of the blood stream in the case of insufficient contractility of the heart.

Effects of using WeChat-assisted perioperative care instructions for parents of pediatric patients undergoing day surgery for herniorrhaphy.

PubMed

Liu, Jun; Zheng, Xin; Chai, Shouxia; Lei, Meirong; Feng, Zehui; Zhang, Xuelin; Lopez, Violeta

2018-02-19

This study examined the effects of WeChat-assisted perioperative instructions for parents whose children were to undergo herniorrhaphy. A randomized controlled trial was conducted in a day surgery center in China. Participants were randomly assigned to the intervention (WeChat) group (n = 209) and the control (Leaflet) group (n = 209). The primary outcomes of this study were parents' knowledge regarding hernia and rate of cancellation of children's surgery. The secondary outcomes were the rate of lost-to-follow-up and the rate of complications and adverse events during the seventh postoperative follow-up day. There was a significant difference in the rate of cancelling the surgery and the mean knowledge score between the WeChat group and leaflet groups. The lost-to-follow-up rate was significantly lower in the WeChat group (0.54%) than in the leaflet group (3.66%). The incidence of postoperative complications were higher in the control group. WeChat-assisted perioperative care instructions enhanced parents' knowledge on perioperative instructions and promoted the preparation of their children for day surgery resulting in lower rate of cancelling the surgery. WeChat has the ability to expand health services outside the hospital confines and could be used as an important low-cost health educational medium in China. Copyright © 2018 Elsevier B.V. All rights reserved.

In-body tissue-engineered aortic valve (Biovalve type VII) architecture based on 3D printer molding.

PubMed

Nakayama, Yasuhide; Takewa, Yoshiaki; Sumikura, Hirohito; Yamanami, Masashi; Matsui, Yuichi; Oie, Tomonori; Kishimoto, Yuichiro; Arakawa, Mamoru; Ohmuma, Kentaro; Tajikawa, Tsutomu; Kanda, Keiichi; Tatsumi, Eisuke

2015-01-01

In-body tissue architecture--a novel and practical regeneration medicine technology--can be used to prepare a completely autologous heart valve, based on the shape of a mold. In this study, a three-dimensional (3D) printer was used to produce the molds. A 3D printer can easily reproduce the 3D-shape and size of native heart valves within several processing hours. For a tri-leaflet, valved conduit with a sinus of Valsalva (Biovalve type VII), the mold was assembled using two conduit parts and three sinus parts produced by the 3D printer. Biovalves were generated from completely autologous connective tissue, containing collagen and fibroblasts, within 2 months following the subcutaneous embedding of the molds (success rate, 27/30). In vitro evaluation, using a pulsatile circulation circuit, showed excellent valvular function with a durability of at least 10 days. Interposed between two expanded polytetrafluoroethylene grafts, the Biovalves (N = 3) were implanted in goats through an apico-aortic bypass procedure. Postoperative echocardiography showed smooth movement of the leaflets with minimal regurgitation under systemic circulation. After 1 month of implantation, smooth white leaflets were observed with minimal thrombus formation. Functional, autologous, 3D-shaped heart valves with clinical application potential were formed following in-body embedding of specially designed molds that were created within several hours by 3D printer. © 2014 Wiley Periodicals, Inc.

Using Behavioural Insights to Promote Food Waste Recycling in Urban Households-Evidence From a Longitudinal Field Experiment.

PubMed

Linder, Noah; Lindahl, Therese; Borgström, Sara

2018-01-01

Promoting pro-environmental behaviour amongst urban dwellers is one of today's greatest sustainability challenges. The aim of this study is to test whether an information intervention, designed based on theories from environmental psychology and behavioural economics, can be effective in promoting recycling of food waste in an urban area. To this end we developed and evaluated an information leaflet, mainly guided by insights from nudging and community-based social marketing. The effect of the intervention was estimated through a natural field experiment in Hökarängen, a suburb of Stockholm city, Sweden, and was evaluated using a difference-in-difference analysis. The results indicate a statistically significant increase in food waste recycled compared to a control group in the research area. The data analysed was on the weight of food waste collected from sorting stations in the research area, and the collection period stretched for almost 2 years, allowing us to study the short- and long term effects of the intervention. Although the immediate positive effect of the leaflet seems to have attenuated over time, results show that there was a significant difference between the control and the treatment group, even 8 months after the leaflet was distributed. Insights from this study can be used to guide development of similar pro-environmental behaviour interventions for other urban areas in Sweden and abroad, improving chances of reaching environmental policy goals.

Self-help smoking cessation and maintenance programs: a comparative study with 12-month follow-up by the American Lung Association.

PubMed Central

Davis, A L; Faust, R; Ordentlich, M

1984-01-01

One thousand two hundred thirty seven smokers responding to lung association announcements in five geographic areas were randomly assigned to one of four groups and mailed American Lung Association materials: 1) leaflets (L); 2) leaflets plus maintenance manual (L + M); 3) cessation manual (C); and 4) cessation and maintenance manuals (C + M). Five telephone interviews over one year achieved a 95 per cent follow-up completion rate. Nonrespondents as well as exclusive cigar and pipe users were classified as smokers. Twenty per cent quit initially, with 5 per cent continually abstinent in (C + M) at 12 months vs 2 per cent in (L) (p less than .05). Nonsmoking prevalence rates (no tobacco smoking in the past month), on the other hand, gradually increased after six months; at 12 months those with the maintenance component, (L + M) and (C + M), had higher rates (18 per cent) than (L) (12 per cent) or (C) (15 per cent). Leaflets and manual alone were least cost effective. Rising nonsmoking prevalence rates observed in all groups suggest that successful attempts to quit increased over time and that a contributing factor might have been the follow-up method. Although achieving lower quit rates than methods requiring attendance at a course, the self-help intervention has the advantages of greater availability, flexibility, and in some instances lower cost. PMID:6437257

27 CFR 5.62 - Definition.

Code of Federal Regulations, 2011 CFR

2011-04-01

... booklet, menu, wine card, leaflet, circular, mailer, book insert, catalog, promotional material, sales....42 of this part. (b) Any editorial or other reading material (i.e., news release) in any periodical...

DOSE-RATE DEPENDENCE OF INSTANTANEOUS PHYSIOLOGICAL RADIATION EFFECTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hug, O.

Nastic movements in Mimosa pudica were induced by x radiation. Using short radiation impulses of 10 to 30 sec and doses up to 120 kr/min, the leaflets were observed to close and the stem to bend in the main joint during the first minute. After irradiation of parts of the leaflet, the reaction spreads along the physiological pathways as in any other stimulus. When the action potential is completed, slow depolarization continues and reaches a maximum, finally returning to the initial value in about two hr. The effect was found to be dose- dependent. It is hypothesized that either amore » direct physicochemical change of the cell membrane or a damage of substances which influence the function of the cell membrane is induced by the irradiation. (H.M.G.)« less

Relief of mitral leaflet tethering following chronic myocardial infarction by chordal cutting diminishes left ventricular remodeling.

PubMed

Messas, Emmanuel; Bel, Alain; Szymanski, Catherine; Cohen, Iris; Touchot, Bernard; Handschumacher, Mark D; Desnos, Michel; Carpentier, Alain; Menasché, Philippe; Hagège, Albert A; Levine, Robert A

2010-11-01

one of the key targets in treating mitral regurgitation (MR) is reducing the otherwise progressive left ventricular (LV) remodeling that exacerbates MR and conveys adverse prognosis. We have previously demonstrated that severing 2 second-order chordae to the anterior mitral leaflet relieves tethering and ischemic MR acutely. The purpose of this study was to test whether this technique reduces the progression of LV remodeling in the chronic ischemic MR setting. a posterolateral MI was created in 18 sheep by obtuse marginal branch ligation. After chronic remodeling and MR development at 3 months, 6 sheep were randomized to sham surgery (control group) and 12 to second-order chordal cutting (6 each to anterior leaflet [AntL] and bileaflet [BiL] chordal cutting, techniques that are in clinical application). At baseline, chronic infarction (3 months), and follow-up at a mean of 6.6 months post-myocardial infarction (MI) (euthanasia), we measured LV end-diastolic (EDV) and end-systolic volume (ESV), ejection fraction, wall motion score index, and posterior leaflet (PL) restriction angle relative to the annulus by 2D and 3D echocardiography. All measurements were comparable among groups at baseline and chronic MI. At euthanasia, AntL and BiL chordal cutting limited the progressive remodeling seen in controls. LVESV increased relative to chronic MI by 109±8.7% in controls versus 30.5±6.1% with chordal cutting (P<0.01) (LVESV in controls, 82.5±2.6 mL; in AntL, 60.6±5.1 mL; in BiL, 61.8±4.1 mL). LVEDV increased by 63±2.0% in controls versus 26±5.5% and 22±3.4% with chordal cutting (P<0.01). LV ejection fraction and wall motion score index were not significantly different at follow-up among the chordal cutting and control groups. MR progressively increased to moderate in controls but decreased to trace-mild with AntL and BiL chordal cutting (MR vena contracta in controls, 5.9±1.1 mm; in AntL, 2.6±0.1 mm; in BiL, 1.7±0.1 mm; P<0.01). BiL chordal cutting provided greater PL mobility (decreased PL restriction angle to 54.2±5.0° versus 83±3.2° with AntL chordal cutting; P<0.01). reduced leaflet tethering by chordal cutting in the chronic post-MI setting substantially decreases the progression of LV remodeling with sustained reduction of MR over a chronic follow-up. These benefits have the potential to improve clinical outcomes.

Mitral Valve Disease

MedlinePlus

... leaflets) that open and close, allowing blood to flow from your left atrium to your left ventricle ... does not open enough to allow sufficient blood flow. Usually this is the result of hardening (calcification) ...

45 CFR 1226.5 - Electoral, voter registration, and other activities.

Code of Federal Regulations, 2011 CFR

2011-10-01

... campaign literature for candidates, including leaflets pamphlets, and material designed for the print or electronic media; (b) Voter Registration Activities. Any voter registration activity, such as (1) Providing...

45 CFR 1226.5 - Electoral, voter registration, and other activities.

Code of Federal Regulations, 2010 CFR

2010-10-01

... campaign literature for candidates, including leaflets pamphlets, and material designed for the print or electronic media; (b) Voter Registration Activities. Any voter registration activity, such as (1) Providing...

Feasibility of a Smartphone website to support antenatal Perineal massage in pregnant women.

PubMed

Takeuchi, Shoko; Horiuchi, Shigeko

2017-10-16

In Japan, 85% of pregnant women do not practice antenatal perineal massage. Therefore, we developed a smartphone website to support the practice of antenatal perineal massage. The purpose of the present study was to evaluate the feasibility of our smartphone website. Pregnant women were recruited at five hospitals or clinics in Tokyo, Japan. Participants assigned to the smartphone website group (n = 74) were asked to register on the smartphone website. After completing registration, they could login and use all the contents of the website. After giving birth, participants completed a 5-item questionnaire evaluating the acceptability of the smartphone website. Participants assigned to the leaflet group (n = 71) received a leaflet on antenatal perineal massage and completed a similar 4-item questionnaire evaluating the leaflet. Data were collected from April 2014 to November 2014. Data analysis was performed using chi-square and t-tests to analyze responses to close-ended questions, and content analysis was conducted to analyze responses of open-ended questions. In the smartphone website group, 9 women (12.2%) did not register on the smartphone website. Approximately 80% of the women who responded indicated that the smartphone site was easy to understand and useful for practicing antenatal perineal massage. In the smartphone website group, the reply rate for reporting the frequency of massage was 43.6%. Although the ratings and frequency at which the material was accessed tended to be higher in the smartphone website group than in the leaflet group, there were no significant differences. Most pregnant women in the smartphone website group provided a favorable evaluation for the smartphone website. However, some participants had suggestions for improvement, which need to be incorporated in a revised version of the website. Therefore, the present study's results demonstrate the feasibility of a smartphone website to support the practice of antenatal perineal massage, and they may aid in the development of similar web-based educational material for pregnant women. This trial was registered with the UMIN Clinical Trials Registry ( UMIN000013979 ) on May 16, 2014.

Patient information leaflets (PILs) for UK randomised controlled trials: a feasibility study exploring whether they contain information to support decision making about trial participation.

PubMed

Gillies, Katie; Huang, Wan; Skea, Zoë; Brehaut, Jamie; Cotton, Seonaidh

2014-02-18

Informed consent is regarded as a cornerstone of ethical healthcare research and is a requirement for most clinical research studies. Guidelines suggest that prospective randomised controlled trial (RCT) participants should understand a basic amount of key information about the RCTs they are being asked to enrol in in order to provide valid informed consent. This information is usually provided to potential participants in a patient information leaflet (PIL). There is evidence that some trial participants fail to understand key components of trial processes or rationale. As such, the existing approach to information provision for potential RCT participants may not be optimal. Decision aids have been used for a variety of treatment and screening decisions to improve knowledge, but focus more on overall decision quality, and may be helpful to those making decisions about participating in an RCT. We investigated the feasibility of using a tool to identify which items recommended for good quality decision making are present in UK PILs. PILs were sampled from UK registered Clinical Trials Unit websites across a range of clinical areas. The evaluation tool, which is based on standards for supporting decision making, was applied to 20 PILs. Two researchers independently rated each PIL using the tool. In addition, word count and readability were assessed. PILs scored poorly on the evaluation tool with the majority of leaflets scoring less than 50%. Specifically, presenting probabilities, clarifying and expressing values and structured guidance in deliberation and communication sub-sections scored consistently poorly. Tool score was associated with word count (r=0.802, P <0.01); there was no association between score and readability (r=-0.372, P=0.106). The tool was feasible to use to evaluate PILs for UK RCTs. PILs did not meet current standards of information to support good quality decision making. Writers of information leaflets could use the evaluation tool as a framework during PIL development to help ensure that items are included which promote and support more informed decisions about trial participation. Further research is required to evaluate the inclusion of such information.

Coordination of xylem hydraulics and stomatal regulation in keeping the integrity of xylem water transport in shoots of two compound-leaved tree species.

PubMed

Liu, Yan-Yan; Song, Jia; Wang, Miao; Li, Na; Niu, Cun-Yang; Hao, Guang-You

2015-12-01

Hydraulic segmentation between proximal and distal organs has been hypothesized to be an important protective mechanism for plants to minimize the detrimental effects of drought-induced hydraulic failure. Uncertainties still exist regarding the degree of segmentation and the role of stomatal regulation in keeping hydraulic integrity of organs at different hierarchies. In the present study, we measured hydraulic conductivity and vulnerability in stems, compound leaf petioles and leaflet laminas of Fraxinus mandshurica Rupr. and Juglans mandshurica Maxim. growing in Changbai Mountain of Northeast China to identify the main locality where hydraulic segmentation occurs along the shoot water transport pathway. Stomatal conductance in response to leaf water potential change was also measured to investigate the role of stomatal regulation in avoiding extensive transpiration-induced embolism. No major contrasts were found between stems and compound leaf petioles in either hydraulic conductivity or vulnerability to drought-induced embolism, whereas a large difference in hydraulic vulnerability exists between compound leaf petioles and leaflet laminas. Furthermore, in contrast to the relatively large safety margins in stems (4.13 and 2.04 MPa) and compound leaf petioles (1.33 and 1.93 MPa), leaflet lamina hydraulic systems have substantially smaller or even negative safety margins (-0.17 and 0.47 MPa) in F. mandshurica and J. mandshurica. Under unstressed water conditions, gas exchange may be better optimized by allowing leaflet vascular system function with small safety margins. In the meantime, hydraulic safety of compound leaf petioles and stems are guaranteed by their large safety margins. In facing severe drought stress, larger safety margins in stems than in compound leaf petioles would allow plants to minimize the risk of catastrophic embolism in stems by sacrificing the whole compound leaves. A strong coordination between hydraulic and stomatal regulation appears to play a critical role in balancing the competing efficiency and safety requirements for xylem water transport and use in plants. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

16 CFR 307.7 - Requirements for disclosure in print advertising.

Code of Federal Regulations, 2010 CFR

2010-01-01

... leaflets, pamphlets, coupons, direct mail circulars, or paperback book inserts; and posters and placards... not immediately next to other written matter or to any circular designs, elements, or similar...

27 CFR 5.41 - Bottle cartons, booklets and leaflets.

Code of Federal Regulations, 2010 CFR

2010-04-01

... TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF DISTILLED SPIRITS Labeling...), or any written, printed, graphic, or other matter accompanying the bottle to the consumer buyer shall...

27 CFR 7.51 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., menu, wine card, leaflet, circular, mailer, book insert, catalog, promotional material, sales pamphlet... labeling under §§ 7.20 through 7.29 of this part. (b) Any editorial or other reading material (i.e., news...

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

Code of Federal Regulations, 2010 CFR

2010-04-01

... TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Labeling Requirements... written, printed, graphic, or other matter accompanying the bottle to the consumer buyer shall not contain...

Mechanism of tricuspid regurgitation in paramembranous ventricular septal defect.

PubMed

Hagler, Donald J; Squarcia, Umberto; Cabalka, Allison K; Connolly, Heidi M; O'Leary, Patrick W

2002-04-01

Literature has been limited in regard to the mechanisms of tricuspid regurgitation (TR) in patients with paramembranous (perimembranous) ventricular septal defect (VSD). Most observations have noted tricuspid valve clefts or dysplasia. We describe another mechanism for production of TR in association with paramembranous VSD. In 8 patients, we found significant TR produced by the VSD jet pushing the tricuspid anterior leaflet forward to open the tricuspid valve orifice. In these patients, a moderate paramembranous VSD extended slightly below the septal tricuspid leaflet with only partial obstruction of the VSD jet. All patients had restrictive VSD with low right ventricular pressure. This mechanism to produce TR was best defined by intraoperative transesophageal echocardiography, but current higher resolution imaging should allow correct diagnosis. We believe that when this mechanism for TR is found in association with a moderate VSD, surgical VSD closure is warranted.

Idiopathic mitral valve disease in a patient presenting with Axenfeld-Rieger syndrome.

PubMed

Antevil, Jared; Umakanthan, Ramanan; Leacche, Marzia; Brewer, Zachary; Solenkova, Natalia; Byrne, John G; Greelish, James P

2009-05-01

A 33-year-old, previously healthy male presented with respiratory distress and underwent intubation. A physical examination revealed a holosystolic murmur and pupillary abnormalities. Echocardiography revealed a flail anterior mitral valve leaflet with ruptured chordae and severe mitral regurgitation. The patient underwent urgent mitral valve replacement and tolerated the procedure well. The mitral valve leaflet was myxomatous and calcified -- an unusual find in such a patient. An ophthalmology consultation was obtained and the patient diagnosed with Axenfeld-Rieger syndrome, a disorder of the anterior ocular chamber that has been associated with cardiac malformations. The present case report adds to the body of literature which suggests a correlation between Axenfeld-Rieger syndrome and valvular abnormalities. Hence, it is believed prudent that patients with Axenfeld-Rieger syndrome should undergo echocardiographic screenings for valvular abnormalities.

Generalization of the swelling method to measure the intrinsic curvature of lipids

NASA Astrophysics Data System (ADS)

Barragán Vidal, I. A.; Müller, M.

2017-12-01

Via computer simulation of a coarse-grained model of two-component lipid bilayers, we compare two methods of measuring the intrinsic curvatures of the constituting monolayers. The first one is a generalization of the swelling method that, in addition to the assumption that the spontaneous curvature linearly depends on the composition of the lipid mixture, incorporates contributions from its elastic energy. The second method measures the effective curvature-composition coupling between the apposing leaflets of bilayer structures (planar bilayers or cylindrical tethers) to extract the spontaneous curvature. Our findings demonstrate that both methods yield consistent results. However, we highlight that the two-leaflet structure inherent to the latter method has the advantage of allowing measurements for mixed lipid systems up to their critical point of demixing as well as in the regime of high concentration (of either species).

[Functional tricuspid regurgitation and its relation to the morphology of the tricuspid valve and annulus: pulsed doppler echocardiography and two-dimensional echocardiography].

PubMed

Mikami, T; Kudo, T; Sakurai, N; Sakamoto, S; Tanabe, Y; Yasuda, H

1983-06-01

The mechanism for the development of functional tricuspid regurgitation (TR) was studied by an ultrasonic method. Thirty-five examinations were performed in 31 patients who were expected to have functional TR, and the severity was classified into 4 grades according to the extension of the regurgitant signals by pulsed Doppler echocardiography. The satisfactory horizontal section of the tricuspid valve was obtained by two-dimensional echocardiography (2DE) to measure the tricuspid annular diameter and to observe systolic configuration of the tricuspid valve in 22 examinations. The tricuspid annular diameter was well correlated with the severity of TR, and "lack of coaptation" of the valve was recognized on 2DE in some cases of severe TR with the markedly dilated annulus, indicating that this dilatation was an important trigger of functional TR. Additionally, in the majority of patients with severe TR, "anterior displacement" of the tips of tricuspid leaflet(s) (6 mm or more from the tricuspid annulus towards the right ventricle) was observed, which was thought to be due to the chordal traction secondary to the right ventricular dilatation, and contributed to the development of functional TR by disturbing sufficient coaptation. In one particular case, severe TR was associated with " malaligned coaptation" caused by the anterior displacement confined to the septal leaflet, indicating that asymmetrical dilatation of the right ventricle and/or disorientation of chordae-valve system may contribute to TR.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid Clustering Correlates with Membrane Curvature as Revealed by Molecular Simulations of Complex Lipid Bilayers

PubMed Central

Koldsø, Heidi; Shorthouse, David; Hélie, Jean; Sansom, Mark S. P.

2014-01-01

Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins. PMID:25340788

Annulus fibrosus of the mitral valve: reality or myth.

PubMed

Berdajs, Denis; Zünd, Gregor; Camenisch, Colette; Schurr, Ulrich; Turina, Marko I; Genoni, Michele

2007-01-01

Surgical repair of the mitral valve is in most cases limited to the posterior leaflet of the mitral valve and to the annulus fibrosus. The term annulus fibrosus is still used in anatomical and clinical terminology and is described as a cord like structure providing the attachment of the mitral vale. However, to date no evidence exists of a ring-or cord-like structure at this area. Herein, we describe the attachment of the mitral valve by using the macroscopical and microscopical techniques. The ventricular attachment of the posterior mitral valve leaflet was investigated in 10 human hearts. In dry dissected specimens, the intraventricular illumination was used to identify the attachment of the mitral valve to the left ventricular muscle. Using the histological techniques, we verified the position of the annulus fibrosus. The attachment of the posterior mitral valve leaflet is a band-like structure positioned between the left ventricular muscle and the left atrium. This fibrous band illustrates the morphological attachment of the mitral valve and, as thus, was interpreted as the annulus fibrosus of the mitral valve. Based on our data, no ring-like structure was found corresponding to the anatomical description of the annulus fibrosus, instead the band-like fibrous tissue was identified positioned between the mitral valve and the left ventricle. Histologicaly, we detected that this structure is part of the greater structural system that is directly connected to the membranous septum, to the left and right fibrous trigone and the attachment aortic root to the left ventricular muscle.

Molecular dynamics simulation of sodium dodecylsulfate (SDS) bilayers.

PubMed

Zhang, Hongshu; Yuan, Shiling; Sun, Jichao; Liu, Jianqiang; Li, Haiping; Du, Na; Hou, Wanguo

2017-11-15

Sodium dodecylsulfate (SDS) - a simple single tailed surfactant (STS) can form stable vesicles from its micellar solution without any additives under the mediation of solid surfaces. To further understand the mechanism of this transition on the molecular level, molecular dynamics simulations are performed to study segments of SDS bilayers (as part of vesicles) in the bulk solution systematically, at the moment that the lower leaflet of bilayers already detached from solid surfaces. The SDS membrane would rather keep their bilayers structure than return to micelles when the initial interdigitated degree (δ i ) between alkyl chains is more than 8.0±1.4%. And the interdigitated degree is always approaching to 31.7±2.0% while the equilibrium is reached. The aggregates behave as curved bilayers, planar bilayers, perforated bilayers, and micelles with the increase of the lower leaflet cross-sectional area. Besides, the structures of salt bridge and water bridge structures are formed between DS - and Na + ions or water molecules, which contribute to the stability of SDS bilayers. The distribution difference of the salt bridges along the direction of S-O axis between the two leaflets leads to the asymmetry of the bilayers, which plays supplementary role to the formation of bilayers curvature. We expect that this work help to shed light on the understanding of interface phenomena and the mechanism of simple single-tailed surfactant vesicle self-assembly on the molecular level. Copyright © 2017 Elsevier Inc. All rights reserved.

mapview - Interactive viewing of spatial data in R

NASA Astrophysics Data System (ADS)

Appelhans, Tim; Detsch, Florian; Reudenbach, Cristoph; Woellauer, Stefan

2016-04-01

In this talk we would like to introduce mapview, an R package designed to aid researchers during their work-flow of spatial data analysis. The package was initially developed within the framework of the DFG funded research group "KiLi - Kilimanjaro ecosystems under global change: Linking biodiversity, biotic interactions and biogeochemical ecosystem processes" but has quickly developed into a general purpose spatial data viewer. mapview provides some powerful tools for interactive visualization of standard spatial data in R. It has support for all Spatial*(DataFrame) objects as well as all Raster* objects. It is designed so that one function call - mapview(x) - is all you need to view the data interactively. Adding layers to existing views is very easy and we have taken great care in providing suitable defaults for features such as background maps or coloring but things can be customized flexibly (and permanently) to suit different needs. Even though mapview is for most parts based on the leaflet package, it is far more than just a convenience wrapper around leaflet functionality. mapview provides additional features for handling big data sets (up to several million points) as well as some specialized functionality to view and compare rasters of any size with arbitrary coordinate reference systems. Given that mapview is merely a bridge between R and the underlying leaflet.js javascript library, mapview can be used to produce web-maps by simply providing the path to a designated folder. This talk will be a live demonstration of some of the key features of mapview.

Using Behavioural Insights to Promote Food Waste Recycling in Urban Households—Evidence From a Longitudinal Field Experiment

PubMed Central

Linder, Noah; Lindahl, Therese; Borgström, Sara

2018-01-01

Promoting pro-environmental behaviour amongst urban dwellers is one of today's greatest sustainability challenges. The aim of this study is to test whether an information intervention, designed based on theories from environmental psychology and behavioural economics, can be effective in promoting recycling of food waste in an urban area. To this end we developed and evaluated an information leaflet, mainly guided by insights from nudging and community-based social marketing. The effect of the intervention was estimated through a natural field experiment in Hökarängen, a suburb of Stockholm city, Sweden, and was evaluated using a difference-in-difference analysis. The results indicate a statistically significant increase in food waste recycled compared to a control group in the research area. The data analysed was on the weight of food waste collected from sorting stations in the research area, and the collection period stretched for almost 2 years, allowing us to study the short- and long term effects of the intervention. Although the immediate positive effect of the leaflet seems to have attenuated over time, results show that there was a significant difference between the control and the treatment group, even 8 months after the leaflet was distributed. Insights from this study can be used to guide development of similar pro-environmental behaviour interventions for other urban areas in Sweden and abroad, improving chances of reaching environmental policy goals. PMID:29623056

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

PubMed Central

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

2014-01-01

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

Interactions and Translational Dynamics of Phosphatidylinositol Bisphosphate (PIP2) Lipids in Asymmetric Lipid Bilayers.

PubMed

Shi, Xiaojun; Kohram, Maryam; Zhuang, Xiaodong; Smith, Adam W

2016-02-23

Phosphatidylinositol phosphate (PIP) lipids are critical to many cell signaling pathways, in part by acting as molecular beacons that recruit peripheral membrane proteins to specific locations within the plasma membrane. Understanding the biophysics of PIP-protein interactions is critical to developing a chemically detailed model of cell communication. Resolving such interactions is challenging, even in model membrane systems, because of the difficulty in preparing PIP-containing membranes with high fluidity and integrity. Here we report on a simple, vesicle-based protocol for preparing asymmetric supported lipid bilayers in which fluorescent PIP lipid analogues are found only on the top leaflet of the supported membrane facing the bulk solution. With this asymmetric distribution of lipids between the leaflets, the fluorescent signal from the PIP lipid analogue reports directly on interactions between the peripheral molecules and the top leaflet of the membrane. Asymmetric PIP-containing bilayers are an ideal platform to investigate the interaction of PIP with peripheral membrane proteins using fluorescence-based imaging approaches. We demonstrate their usefulness here with a combined fluorescence correlation spectroscopy and single particle tracking study of the interaction between PIP2 lipids and a polycationic polymer, quaternized polyvinylpyridine (QPVP). With this approach we are able to quantify the microscopic features of the mobility coupling between PIP2 lipids and polybasic QPVP. With single particle tracking we observe individual PIP2 lipids switch from Brownian to intermittent motion as they become transiently trapped by QPVP.

The 'respect rather than resect' principle in mitral valve repair: the lateral dislocation of the P2 technique.

PubMed

Zanobini, Marco; Ricciardi, Gabriella; Mammana, Francesco Liborio; Kassem, Samer; Poggio, Paolo; Di Minno, Alessandro; Cavallotti, L; Saccocci, Matteo

2017-09-01

Leaflet resection represents the reference standard for surgical treatment of mitral valve (MV) regurgitation. New approaches recently proposed place emphasis on respecting, rather than resecting, the leaflet tissue to avoid the drawbacks of the 'resection' approach. The lateral dislocation of mid portion of mitral posterior leaflet (P2) technique for MV repair is a nonresectional technique in which the prolapsed P2 segment is sutured to normal P1 segment. Our study evaluates the effectiveness of this technique. We performed the procedure on seven patients. Once ring annular sutures were placed, the prolapsed P2 segment was dislocated toward the normal P1 segment with a rotation of 90° and without any resection. If present, residual clefts between P2 and P3 segments were closed. Once the absence of residual mitral regurgitation is confirmed by saline pressure test, ring annuloplasty was completed. The valve was evaluated using transesophageal echocardiography in the operating room and by transthoracic echocardiography before discharge. At the last follow-up visit, transthoracic echocardiography revealed no mitral regurgitation and normal TRANSVALVULAR gradients. The lateral dislocation of P2 is an easily fine-tuned technique for isolated P2 prolapse, with the advantage of short aortic cross-clamp and cardiopulmonary bypass times. We think it might be very favorable in older and frail patients. Long-term follow-up is necessary to assess the durability of this technique.