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Cell Boundaries (cell + boundary)
Selected AbstractsAnalysis of hair lipids and tensile properties as a function of distance from scalpINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2005L. Duvel Synopsis Cuticle cells form the outer covering surrounding and protecting the cortex. The cuticle cells are thin, flat and overlap, and intercellular lipid lamellae are found in the gaps between the cell boundaries. The lipid lamellae are also found within the cortex in the cell boundaries between the long fribrous corticle cells. In addition, the outer surfaces of the cuticle cells are covered by a monolayer of covalently bound fatty acids, a major component of which is 18-methyleicosanoic acid. The fatty acids are thought to be attached through thio-ester linkages. Together these lipids are thought to be major determinants of the physical properties of the hair. The present study tested the hypothesis that both free and covalently bound lipids are progressively lost during normal environmental exposures. This progressive loss within the cuticle layers may, in part, lead to an increased susceptibility of the protein and lipid lamellae in the cortex to degradation. This degradation, in turn, would contribute to a progressive decrease in the tensile properties of the hair. Research grade hair was cut into five segments from the root to the distal end. Lipids from each segment were extracted and analyzed by thin-layer chromatography in conjunction with photodensitometry. The major free polar lipid classes in the hair included ceramides, glucosylceramides and cholesterol sulfate. The concentrations of all of the free polar lipids as well as the covalently bound fatty acids decreased in going from the root to the distal end of the hair. In addition, there was a significant reduction in tensile properties of the hair from the root to distal end. In conclusion, the progressive loss of endogenous free and covalently bound lipids from hair, which are probably related to normal weathering of the hair and grooming practices, may help contribute to a marked decrease in tensile properties to the hair. Résumé Les cellules de la cuticule forment le revêtement externe qui protège le cortex des cheveux. Les cellules de la cuticule sont minces, plates et se chevauchent. De fines couches de lipides sont présentes dans le matériau assurant la jonction entre les cellules cuticulaires. D'autres fines couches de lipides sont également présentes dans les espaces intercellulaires du cortex, entre les longues cellules corticales fibreuses. De plus, les surfaces externes des cellules de la cuticule sont recouvertes d'une couche monomoléculaire d'acides gras liés par covalence, un des composants majoritaires étant l'acide 18-méthyleicosanoique. On pense que ces acides gras sont fixés par liaisons thioesters. On pense également que l'ensemble de ces lipides joue un rôle important sur les propriétés physiques du cheveu. L'hypothèse testée dans cette étude est que les lipides libres et ceux liés par covalence sont progressivement éliminés lors de l'exposition normale des cheveux à l'environnement extérieur. Cette délipidation progressive de la cuticule pourrait, en partie, entraîner une plus grande sensibilité des constituants lipidiques et protéiniques du cortex aux agressions externes et accroître leur dégradation. Cette dégradation, à son tour, contribuerait à une diminution progressive des propriétés mécaniques en extension des cheveux. Des cheveux de provenance commerciale ont été coupés en cinq segments de leur racine à leur extrémité distale. Les lipides de chaque segment ont été extraits, séparés par chromatographie couche mince et dosés par densitométrie photographique. Les classes majoritaires de lipides polaires libres sont constituées de céramides, de glucosylcéramides et de sulfate de cholestérol. Les teneurs de tous les lipides polaires libres ainsi que des acides gras liés par covalence diminuent de la racine à l'extrémité distale du cheveu. De plus, on constate une réduction considérable des propriétés mécaniques en extension des cheveux de la racine à l'extrémité distale.-.En conclusion, la perte progressive des lipides endogènes libres et liés par covalence, probablement attribuables aux expositions à l'environnement et au stress des traitements capillaires peut aider à contribuer à une baisse marquée des propriétés mécaniques en extension des cheveux. [source] Peripheral Nerve pericytes originating from the blood,nerve barrier expresses tight junctional molecules and transporters as barrier-forming cellsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2008Fumitaka Shimizu The objective of this study was to establish pure blood,nerve barrier (BNB)-derived peripheral nerve pericyte cell lines and to investigate their unique properties as barrier-forming cells. We isolated peripheral nerve, brain, and lung pericytes from transgenic rats harboring the temperature-sensitive simian virus 40 large T-antigen gene. These cell lines expressed several pericyte markers such as ,-smooth muscle actin, NG2, osteopontin, and desmin, whereas they did not express endothelial cell markers such as vWF and PECAM. In addition, these cell lines expressed several tight junction molecules such as occludin, claudin-12, ZO-1, and ZO-2. In particular, the expression of occludin was detected in peripheral nerve and brain pericytes, although it was not detected in lung pericytes by a Western blot analysis. An immunocytochemical analysis confirmed that occludin and ZO-1 were localized at the cell,cell boundaries among the pericytes. Brain and peripheral nerve pericytes also showed significantly higher trans-pericyte electrical resistance values and lower inulin clearances than lung pericytes. We considered that occludin localized at the cell,cell boundaries among the pericytes might mechanically stabilize the microvessels of the BNB and the blood,brain barrier. Furthermore, we also showed that these cell lines expressed many barrier-related transporters. ABCG2, p-gp, MRP-1, and Glut-1 were detected by a Western blot analysis and were observed in the cytoplasm and outer membrane by an immunocytochemical analysis. These transporters on pericytes might facilitate the peripheral nerve-to-blood efflux and blood-to-peripheral nerve influx transport of substrates in cooperation with those on endothelial cells in order to maintain peripheral nerve homeostasis. J. Cell. Physiol. 217: 388,399, 2008. © 2008 Wiley-Liss, Inc. [source] E-cadherin expression in follicular carcinoma of the thyroidPATHOLOGY INTERNATIONAL, Issue 1 2002Noriko Kato Follicular carcinoma (FC) of the thyroid is distinguished from follicular adenoma (FA) by confirmation of invasion or metastasis. However, it is still unknown how FC acquires the potential for invasion or metastasis. Twenty early FC (pT1 and pT2) were analyzed for immunohistochemical E-cadherin (E-CD) expression. Four of four (100%) widely invasive FC showed reduced E-CD expression, whereas only two of 16 minimally invasive FC showed reduced expression. In most of the minimally invasive FC, both E-CD and , -catenin were expressed on cell,cell boundaries, even in areas where capsular invasion occurred. These results suggest that the mechanism of invasion may be different between widely invasive FC and minimally invasive FC, and that E-CD is probably responsible for the invasion of widely invasive FC. Analysis of methylation of the E-CD gene promoter using the methylation-specific polymerase chain reaction (MSP) method revealed no methylated alleles in the DNA from FC. [source] 3131: Endothelial involvement indicates disease activity in Herpes simplex virus keratitisACTA OPHTHALMOLOGICA, Issue 2010T HILLENAAR Purpose Corneal endotheliitis is a potentially sight-threatening clinical manifestation of herpes simplex virus (HSV) keratitis. Early detection and consequent treatment may prevent development of endothelial decompensation. The goal of this previously published study was to describe the morphological features, frequency, and clinical consequences of endothelial involvement in HSV keratitis as seen by in vivo confocal microscopy (IVCM). Methods We examined both eyes of 250 patients with HSV keratitis by slit-lamp and IVCM. All examinations were assessed for endothelial deviations characteristic of endotheliitis. To determine the specificity, we reviewed our IVCM database for morphologically comparable alterations. This database included 200 healthy volunteers and 1400 patients with various corneal pathologies. The endothelial cell density (ECD) change between the first and last visits of patients with HSV keratitis was evaluated. Results Endotheliitis-specific deviations were detected in 107 of 250 patients with HSV keratitis (43%). Pseudoguttata, enlarged intercellular gaps, infiltration of inflammatory cells into the endothelial layer, loss of defined cell boundaries, spot-like holes, and endothelial denudation disappeared within 3 weeks with appropriate antiviral and anti-inflammatory treatment. Alterations were non-specific for HSV keratitis. Similar alterations were detected in adenoviral, fungal, bacterial, and acanthamoeba keratitis. The HSV affected eyes with endothelial involvement showed a mean ECD decrease of 10.3% per year. Conclusion Endothelial involvement indicates inflammatory activity in HSV keratitis and is associated with irreversible endothelial cell loss. IVCM allows early detection and follow up of endotheliitis-specific alterations. [source] The geometry and motion of nematode sperm cellsCYTOSKELETON, Issue 6 2009Evgeny Demekhin Abstract The nematode sperm cell crawls by recycling major sperm protein (MSP) from dimers into subfilaments, filaments, and filament complexes, as a result of thermal writhing in the presence of hydrophobic patches. Polymerization near leading edges of the cell intercolates MSP dimers onto the tips of growing filament complexes, forcing them against the cell boundary, and extending the cytoskeleton in the direction of motion. Strong adhesive forces attach the cell to the substrate in the forward part of the lamellipod, while depolymerization in the rearward part of the cell breaks down the cytoskeleton, contracting the lamellipod and pulling the cell body forward. The movement of these cells, then, is caused by coordinated protrusive, adhesive and contractile forces, spatially separated across the lamellipod. This paper considers a phenomenological model that tracks discrete elements of the cytoskeleton in curvilinear coordinates. The pseudo-two dimensional model primarily considers protrusion and rotation of the cell, along with the evolution of the cell boundary. General assumptions are that pH levels within the lamellipod regulate protrusion, contraction and adhesion, and that growth of the cytoskeleton, over time, is perpendicular to the evolving cell boundary. The model follows the growth and contraction of a discrete number of MSP fiber complexes, since they appear to be the principle contributors for force generation in cell boundary protrusion and contraction, and the backbone for the dynamic geometry and motion. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] A further work on multi-phase two-fluid approach for compressible multi-phase flowsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 8 2008Yang-Yao Niu Abstract This paper is to continue our previous work Niu (Int. J. Numer. Meth. Fluids 2001; 36:351,371) on solving a two-fluid model for compressible liquid,gas flows using the AUSMDV scheme. We first propose a pressure,velocity-based diffusion term originally derived from AUSMDV scheme Wada and Liou (SIAM J. Sci. Comput. 1997; 18(3):633,657) to enhance its robustness. The scheme can be applied to gas and liquid fluids universally. We then employ the stratified flow model Chang and Liou (J. Comput. Physics 2007; 225:240,873) for spatial discretization. By defining the fluids in different regions and introducing inter-phasic force on cell boundary, the stratified flow model allows the conservation laws to be applied on each phase, and therefore, it is able to capture fluid discontinuities, such as the fluid interfaces and shock waves, accurately. Several benchmark tests are studied, including the Ransom's Faucet problem, 1D air,water shock tube problems, 2D shock-water column and 2D shock-bubble interaction problems. The results indicate that the incorporation of the new dissipation into AUSM+ -up scheme and the stratified flow model is simple, accurate and robust enough for the compressible multi-phase flows. Copyright © 2008 John Wiley & Sons, Ltd. [source] p120 catenin is associated with desmogleins when desmosomes are assembled in high-Ca2+ medium but not when disassembled in low-Ca2+ medium in DJM-1 cellsTHE JOURNAL OF DERMATOLOGY, Issue 6 2008Miho KANNO ABSTRACT We recently showed that p120 catenin (p120ctn), which is an armadillo family protein member that binds to E-cadherin (E-cad), is also localized to desmosomes by directly or indirectly binding to desmogleins (Dsg). We examined whether p120ctn is associated with Dsg1 and Dsg3, as compared with E-cad and plakoglobin (PG), in keratinocytes grown in high or low Ca2+, using a human squamous cell carcinoma cell line, DJM-1 cells. The cell lysate of DJM-1 cells grown in high- or low-Ca2+ media was immunoprecipitated with anti-Dsg1/2 and Dsg3 antibodies, and we examined whether p120ctn is associated with Dsg1 and Dsg3. Then, we observed the co-localization between Dsg3 and p120ctn in cells grown in high- or low-Ca2+ medium on double-staining immunofluorescence microscopy using anti-p120ctn and anti-Dsg3 antibodies. Immunoprecipitates with anti-Dsg1/2 and Dsg3 antibodies in cells grown in high-Ca2+ medium contained p120ctn. In contrast, in low-Ca2+ medium, p120ctn was co-immunoprecipitated with neither Dsg1 nor Dsg3, but was co-immunoprecipitated with E-cad in cells grown in both high- and low-Ca2+ media. Dsg3 was associated with PG in cells grown in both low- and high-Ca2+ media. On immunofluorescence microscopy, p120ctn and Dsg3 were independently observed in cells grown in low-Ca2+ medium; p120ctn, but not Dsg3, was observed in a linear pattern at the cell,cell boundary. However, they were co-localized at cell,cell contacts in cells grown in high-Ca2+ medium. Thus, these proteins are not co-localized in low Ca2+ medium. These results suggest that p120ctn plays an important role in Ca2+ -induced desmosome formation. [source] | |||||||||||||