Human meibum was targetly analyzed for the presence of intact wax esters (WEs) and related compounds by means reverse-phase HPLC in combination with ion trap mass spectrometry. The major detected WEs were based on C(18:n) (n = 1-4) unsaturated FAs ranking following order abundance: C(18:1)>C(18:2)>C(18:3)>C(18:4). fatty alcohols (FAls) found WE saturated nature varied from C(18:0) to C(28:0). three most abundant species C(18:1)-FA C(24:0), C(25:0), C(26:0)-FAl. Typically, a compound FAl...

purpose. To qualitatively compare the nonpolar lipids present in meibomian gland (MG) secretions (samples T1) with aqueous tears (AT) collected from lower tear menisci of healthy, non–dry eye volunteers using either glass microcapillaries T2) or Schirmer test strips T3). methods. Samples T1 to T3 were analyzed use high-pressure liquid chromatography/positive ion mode atmospheric pressure chemical ionization mass spectrometry. Where possible, unknown compared known standards. results. had...

To investigate the potential effect of dietary supplementation with omega-3 fatty acid on lipid composition meibum, aqueous tear evaporation, and volume in patients dry eye.In a pilot, prospective, randomized, double-masked study, eye received daily dose fish oil, containing 450 mg eicosapentaenoic acid, 300 docosahexaenoic 1000 flaxseed oil (TheraTears Nutrition; Advanced Vision Research, Woburn, MA) for 90 days. There were 2 patient visits: baseline final. At these visits, completed ocular...

The purpose of this study was to structurally characterize the major lipid species present in human meibomian gland secretions (MGS) individual subjects by means ion trap atmospheric pressure ionization mass spectrometry analysis (API MSn). samples MGS and authentic standards were analyzed direct infusion high-pressure liquid chromatography (HPLC) experiments with API MSn detection analytes (HPLC precursor ions isolated subjected further sequential fragmentation experiments, their patterns...

Human meibomian gland secretions (also known as meibum) were analyzed for the presence of cholesteryl esters (Chl-E) using HPLC in combination with atmospheric pressure chemical ionization mass spectrometry. A special procedure based on detection in-source generated ion m/z 369 was developed to monitor all Chl-E simultaneously. The structures detected compounds studied and postsource fragmentation precursor (M+H)(+) ions. In concordance previous studies, found tested samples comprised...

Abstract The purpose of the study was to qualitatively characterize major lipid species present in human meibomian gland secretions (MGS) by means high‐performance liquid chromatography with atmospheric pressure ionization mass spectrometric detection analytes (NP HPLC‐MS). Two different NP HPLC‐MS methods have been developed analyze that were expected be MGS. first method optimized for analysis relatively nonpolar lipids [wax esters (WE), di‐ and triacyl glycerols (DAG TAG), cholesterol...

Purpose.: Secretions that are produced by meibomian glands (also known as meibum) a major source of lipids for the ocular surface humans and animals alike. Many animal species have been evaluated their lipidomes. However, there very small number studies in which were compared with side side. Therefore, purpose this study was to compare meibum collected from three typical laboratory animals, canines, mice, rabbits, lipid composition order determine most resembles humans. Methods.: High...

Meibomian gland dysfunction (MGD) is one of the main causes dry eye disease. To better understand physiological functions human meibomian glands (MGs), present study compared MGs with free sebaceous (SGs) and hair-associated SGs humans using morphological, immunohistochemical, liquid chromatography—mass spectrometry (LCMS)-based lipidomic approaches. Eyelids MGs, nostrils, lips, external auditory canals SGs, scalp body donors were probed antibodies against cytokeratins (CK) 1, 8, 10, 14,...

Protein kinase C (PKC) isoenzymes are essential components of cell signaling. In this study, we investigated the regulation PKC-alpha in murine B16 amelanotic melanoma (B16a) cells by monohydroxy fatty acids 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] and 13(S)-hydroxyoctadecadienoic [13(S)-HODE]. 12(S)-HETE induced a translocation to plasma membrane focal adhesion plaques, leading enhanced B16a matrix protein fibronectin. However, 13(S)-HODE inhibited these effects on PKC-alpha. A...

Purpose. To quantitatively explore the relationship between low relative humidity conditions, as experienced in airplane cabins during flight, and increases aqueous tear evaporation a potential explanation for increased dry eye symptoms noted by people when environmental conditions. Methods. Prospective experimental laboratory study. Evaporative rates under two different ranges of increasing humidity, from 20% to 25% (similar or arid regions) 40% 45% nonarid regions), were obtained 18...

Wax esters (WE) of human meibum are one the largest group meibomian lipids. Their complete characterization on level individual intact lipid species has not been completed yet. We obtained detailed structural information previously uncharacterized WE.Intact WE were separated and analyzed by means high-temperature capillary gas-liquid chromatography (GLC) in combination with low voltage (30 eV) electron ionization ion trap mass spectrometry (ITMS). 3D (mass-to-charge ratio [m/z] versus sample...

To study melting characteristics and the morphology of human mouse meibum.Hot stage cross-polarized light microscopy (HSPM) immunohistochemical approaches were used.Isolated meibum, meibum mice (either isolated or within meibomian ducts mice), found to be in liquid-crystal state at physiological temperatures. Melting both types started approximately 10°C was completed 40°C. curves inside multiphasic with least two three clearly defined phase transition temperatures, typically 12 ± 2°C (minor...

Human meibomian gland secretions (meibum) are the major lipid component of human preocular tear film. The predominant classes found in meibum include waxes (WE), cholesteryl esters (CE), and varying amounts cholesterol (Chl). classical sulfo-phospho-vanillin assay (SPVA), adapted for a microplate reader, was used to quantitate lipids meibum. To account reactivities different SPVA, model mixture (MMx) that approximated WE/CE/Chl composition developed lipids. overall SPV responses MMx were be...

purpose. Tear lipocalin (Tlc) is a major lipid binding protein in tears and thought to have an important role stabilizing the Meibomian layer by transferring lipids it from aqueous or ocular surface, adsorbing directly. These possible roles been investigated vitro using human Tlc. methods. Tlc was purified size exclusion chromatography followed ion exchange chromatography. Three additional samples of were prepared lipidation, delipidation, relipidation. The extracted analyzed HPLC-MS...