Abstract:
:It has long been assumed that unstimulated tears are more thoroughly equilibrated with epithelial secretions than stimulated tears, since they are in contact with tarsal, bulbar and corneal surfaces for longer. It was also believed from results with model solutions that soluble mucin is responsible for the observed surface tension and viscosity of tears. If longer contact means more mucin is dissolved in the aqueous tears, then the surface activity (surface tension lowered by mucin) and viscosity (raised by mucin) of tears should therefore be enhanced in unstimulated over stimulated tears. Pools of stimulated and minimally-stimulated tears were collected from a group of healthy adult volunteers by glass capillary. Viscosities were measured in the Contraves Low Shear 30 rheometer over the range of shear rates 0-130 sec-1. Surface tension was measured in the collection capillaries by a micro-technique, before and after refrigerated storage. Both surface tension and viscosity were determined for a variety of tear proteins and mucins. No significant difference was found between the viscosity/shear rate plots of stimulated and unstimulated tear samples. The viscosities of solutions of individual tear proteins were low, except for the combination of lysozyme and secretory IgA. Surface tensions were also similar in both cases, and unchanged by storage at room temperature or refrigeration, indicating no significant loss of surface-active material by adsorption on the capillary walls. Results with model mucin solutions gave a variety of results indicating either little surface activity or losses due to wall adsorption. Tear proteins, individually or in combination, did not lower surface tension to the level of tears. Tear viscosity seems not to depend on the level of dissolved mucins. This suggests either that a constant level of these is picked up even by short-term contact with ocular surfaces, or that viscosity arises from currently unknown materials which vary little with tear flow rate. This type of shear-dependent viscosity is most easily simulated in model solutions with polyionic linear macromolecules, including mucins. The contribution of individual proteins to overall viscosity is small, but combinations including lysozyme show tear-like characteristics, and may indicate that proteins whose concentration is relatively independent of tear flow rate combine with other tear components (possibly including mucins or lipids) to produce their full effect on tear viscosity. The surface tension results suggest that mucins are not of primary importance. Theories of tear film structure and performance need revision.
journal_name
Exp Eye Resjournal_title
Experimental eye researchauthors
Pandit JC,Nagyová B,Bron AJ,Tiffany JMdoi
10.1006/exer.1998.0600keywords:
subject
Has Abstractpub_date
1999-02-01 00:00:00pages
247-53issue
2eissn
0014-4835issn
1096-0007pii
S0014-4835(98)90600-5journal_volume
68pub_type
杂志文章abstract::Prostaglandin E2 (PGE2) markedly reduces intraocular pressure (IOP) when applied topically and induces strong relaxation of pre-contracted isolated ciliary muscle through PGE2 receptor. Because the ciliary muscle relaxation reduces IOP by enhancing uveoscleral aqueous outflow, the ciliary muscle where the existence of...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1006/exer.1999.0829
更新日期:2000-05-01 00:00:00
abstract::Protein myristoylation occurs when the 14 carbon fatty acid, myristic acid, is covalently attached by amide linkage to a protein's N -terminal glycine by an N -terminal myristoyltransferase (NMT). A variation of this called heterogeneous acylation occurs in vivo only in retina when specific proteins are modified by my...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1006/exer.2002.1189
更新日期:2002-07-01 00:00:00
abstract::Lactoferrin plays an important role in the defense against infections, including herpes simplex virus (HSV) keratitis. We studied the impact of three single nucleotide polymorphisms in the human lactoferrin gene on the susceptibility to HSV infections of the eye and the severity of such infections. Lactoferrin gene po...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2007.09.013
更新日期:2008-01-01 00:00:00
abstract::Two low-Ca2+-requiring proteases (calpain I) and one high-Ca2+-requiring protease (calpain II) have been separated from the cytosol of rat retina by DEAE-cellulose column chromatography. Calpain I was half-maximally activated at 3 microM free Ca2+ and fully activated at 10 microM free Ca2+. Half-maximal activation of ...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(85)90098-3
更新日期:1985-07-01 00:00:00
abstract::The majority of dry eye symptoms are due to a chronic inflammation of the lacrimal functional unit resulting in a loss of tear film integrity and normal function. This leads to a reduction in the ability of the ocular surface to respond to environmental challenges. The underlying cause of tear film dysfunction is the ...
journal_title:Experimental eye research
pub_type: 杂志文章,评审
doi:10.1016/j.exer.2003.09.003
更新日期:2004-03-01 00:00:00
abstract::Functional atrophy and accompanying lymphocytic infiltration and destruction of the lacrimal gland (LG) are characteristics of Sjögren's Syndrome (SjS). The male NOD mouse is an experimental model for the autoimmune exocrinopathy that develops in the LG of SjS patients. Acinar cells in LG of male NOD mice aged 3-4 mon...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2009.03.020
更新日期:2009-09-01 00:00:00
abstract::The spontaneously hypertensive rats (SHR) show a lower intraocular pressure--despite high arterial blood pressure--than the normotensive Wistar Kyoto rats (NR). In SHR the quantitative evaluation of resin casts and flat-mount preparations of the blood vessels of the ciliary body and choroid showed a significant dilati...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(85)90004-1
更新日期:1985-02-01 00:00:00
abstract::This study was performed to further characterize expression and function of the Fas/Fas ligand system in the cornea. Specifically, these experiments examined (1) the effect of genetic inactivation of Fas or Fas ligand genes on keratocyte apoptosis in response to corneal epithelial wounding, (2) whether cultured human ...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1006/exer.1997.0371
更新日期:1997-10-01 00:00:00
abstract::A lens serine proteinase with trypsin-like specificity has been purified to homogeneity. This is one of two serine proteinases associated with the alpha-crystallin fraction from bovine lens. The purification was accomplished by a combination of isoelectric precipitation, activation to release the proteinase, gel-filtr...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(83)90135-5
更新日期:1983-12-01 00:00:00
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journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2019.107828
更新日期:2019-12-01 00:00:00
abstract::The effect of kainic acid (KA) on rat retinal morphology was investigated with emphasis on the ganglion cell layer. Two hours after intraocular injection of KA, 70% of the neurones in the ganglion cell layer display morphological alterations. These alterations at the ultrastructural level include the absence of identi...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(83)90014-3
更新日期:1983-02-01 00:00:00
abstract::Over the past 40 years, several groups have shown that epithelial debridement results in the death of keratocytes subjacent to the wound area. More recently this cell death has been shown to involve apoptosis. The purpose of this project was to examine the proliferative response of the normally quiescent keratocytes t...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1006/exer.2000.0926
更新日期:2001-01-01 00:00:00
abstract::Giant papillae, characteristic lesions of vernal keratoconjunctivitis, are formed as a result of the proliferation of conjunctival fibroblasts, the deposition of extracellular matrix, and the infiltration of inflammatory cells. The concentration of interleukin (IL)-4 is also increased in the tear fluid of individuals ...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/s0014-4835(02)00248-8
更新日期:2003-01-01 00:00:00
abstract::The protein phosphatase 2B inhibitor, FK506, is an immunomodulatory polypeptide that has neuroprotective properties, the mechanisms of which have not been elucidated. A possible mechanism may be phosphorylation-mediated regulation of glutamate transporter activity. In the present study, we investigated the effect of F...
journal_title:Experimental eye research
pub_type: 信件
doi:10.1016/j.exer.2010.04.011
更新日期:2010-08-01 00:00:00
abstract::We sequenced selected peptides of alligator rhodopsin that accounted for about half of the total protein. These sequences were confirmed when the total primary structure of alligator rhodopsin was deduced from the cDNA sequence. Differences in the amino-terminal region, compared to that of bovine rhodopsin, account fo...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/s0014-4835(05)80051-x
更新日期:1995-11-01 00:00:00
abstract::The effect of acute exposure to various intensities of white light on visual behavior and retinal structure was evaluated in the T4R RHO dog, a naturally-occurring model of autosomal dominant retinitis pigmentosa due to a mutation in the Rhodopsin gene. A total of 14 dogs (ages: 4-5.5 months) were used in this study: ...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2016.04.006
更新日期:2016-05-01 00:00:00
abstract::The mass receptor potential of the excised, superfused retina of the bullfrog was studied. Photoreceptor responses were isolated by addition of sodium aspartate to the Ringer solutions. Responses of the cones were monitored independently from responses of the rods by employing a two-flash method of stimulation which t...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(84)90007-1
更新日期:1984-08-01 00:00:00
abstract::The polypeptides in portions of human lens epithelium from individuals of various ages were resolved by two-dimensional (2D) gel electrophoresis. The epithelium was divided into a central area of 12.5 mm2, a surrounding area of 50.2 mm2, and an area which was outside of this region. The proteins were solubilized in ur...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(91)90064-l
更新日期:1991-05-01 00:00:00
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journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2016.02.010
更新日期:2016-04-01 00:00:00
abstract::The Royal College of Surgeons (RCS) rat is an established animal model of retinitis pigmentosa, a family of inherited retinal diseases which starts with loss of peripheral vision and progresses to eventual blindness. Blood flow (BF), an important physiological parameter, is intricately coupled to metabolic function un...
journal_title:Experimental eye research
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doi:10.1016/j.exer.2012.06.006
更新日期:2012-08-01 00:00:00
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journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2013.10.020
更新日期:2014-01-01 00:00:00
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journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2017.10.022
更新日期:2018-01-01 00:00:00
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journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1006/exer.1997.0444
更新日期:1998-02-01 00:00:00
abstract::Ultraviolet A (UVA) light-based photoactivation of riboflavin (Rf) to induce corneal crosslinking (CXL) and mechanical stiffening is now a well-known treatment for corneal ectasia and Keratoconus that is being used in a topographically guided photorefractive intrastromal CXL (PiXL) procedure to treat low degrees of re...
journal_title:Experimental eye research
pub_type: 杂志文章,评审
doi:10.1016/j.exer.2020.108199
更新日期:2020-10-01 00:00:00
abstract::The current study investigates the cellular events which trigger activation of proapoptotic Bcl-2-associated × protein (Bax) in retinal cell death induced by all-trans-retinal (atRAL). Cellular events which activate Bax, such as DNA damage by oxidative stress and phosphorylation of p53, were evaluated by immunochemica...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2014.04.003
更新日期:2014-06-01 00:00:00
abstract::Previous histochemical and biochemical studies have documented the presence of carbohydrate-containing molecules in the retinal interphotoreceptor matrix (IPM). The lectin peanut agglutinin (PNA), which preferentially binds galactose-containing carbohydrates, especially galactose-galactosamine linkages, selectively la...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/s0014-4835(87)80163-x
更新日期:1987-04-01 00:00:00
abstract::Müller cells (MC) represent a key element for the metabolic and functional regulation of the vertebrate retina. The aim of the present study was to test the feasibility of a new method for the in-vivo detection and quantification of extrafoveal MC in human retina. We developed a new approach to isolate and analyse ext...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/j.exer.2020.108183
更新日期:2020-10-01 00:00:00
abstract::The authors sought to evaluate the effect of linoleic acid hydroperoxide (18:2/LHP) in promoting choroidal neovascularization (CNV). Albino male rabbits received a subretinal injection of various amounts of LHP (ranging from 5 to 200 microg) dissolved in 50 microl of sodium borate buffer. Control eyes received the buf...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1006/exer.2001.1121
更新日期:2002-02-01 00:00:00
abstract::Axial-length and refraction measurements are presented for the lid-sutured rhesus monkey at 6-month intervals during the first 1.5 years of life. The experimental data are fitted to an exponential growth theory allowing the calculation of time constants, apparent time origins, and correlation coefficients for 10 eyes ...
journal_title:Experimental eye research
pub_type: 杂志文章
doi:10.1016/0014-4835(86)90043-6
更新日期:1986-06-01 00:00:00
abstract::This review summarizes the Ernst H. Bárány Prize Lecture given at the meeting of the International Society of Eye Research in Geneva 2002. In the paper the path from the author's early studies on neurogenic inflammation in the eye to the search for a suitable prostaglandin analogue for glaucoma treatment, and the deve...
journal_title:Experimental eye research
pub_type: 杂志文章,评审
doi:10.1016/j.exer.2003.11.016
更新日期:2004-04-01 00:00:00