John T. Landrum

Optical density spectra of the macular pigmentin vivo andin vitro

A precise relative optical density spectrum of the macular pigment, based upon its dichroic properties, was determined. The spectrum proved essentially identical to that of liposome-bound zeaxanthin and lutein, a system duplicating the macular pigment and its environment. Substantial agreement was also found with the spectra of Wyszecki and Stiles (1982, Color science: Concepts and methods, quantitative data and formulae. New York: Wiley) and Vos (1972, Institute for Perception, RVO-TNO, IZF 1972-17, Soesterberg, The Netherlands), and the latter is recommended as a standard. For 7 subjects, the pigment density spectrum derived from foveal and extra-foveal sensitivities was compared with the dichroism-based spectrum. Results indicated that the pigment is described by a common distribution of molecular orientations for all subjects.

The Macular Pigment: A Possible Role in Protection from Age-Related Macular Degeneration

Publisher Summary The macula is the anatomical region of the retina that is responsible for central vision. Considerable effort is devoted to understanding and treating diseases that disrupt the normal functioning of the macula. Such a disease is age-related maculardegeneration (AMD). It is the leading cause of visual impairment in the United States and is an irreversible condition. Factors with an apparent positive correlation with AMD include light skin color, light iris color, high exposure to ambient light, low levels of dietary xanthophylis, and low levels of serum xanthophylls. This chapter reviews the current state of knowledge of the macular pigment, AMD, and the possible link between them and presents data that indicate that lower than normal amounts of macular pigment are found in persons with AMD. The chapter details the macula, the macular pigment, and age-related macular degeneration. Various methods are discussed; analysis of carotenoids from eyes—tissue samples, carotenoid extraction and analysis, and stereoisomer analysis. There is uptake of lutein in human adults—sampling, carotenoid extraction, and HPLC analysis. There are notes on heterochromatic flicker photometry, apparatus, and measurements. Data from 15 control and 22 AMD eyes have been obtained to date. The results, for each eye studied, depicts the total carotenoid present in each of the three sections of the retina in picomoles per square millimeter of tissue. The chapter also discusses lutein uptake in human subjects and macular pigmentation. This chapter has shown that serum levels increase significantly in subjects supplemented with lutein at a dosage level of 30 mg/day. The slow rate of Macular pigmentation increase may be partly because of the need for lutein to diffuse into the avascular macular region of the retina. The increase is not always bilaterally symmetric. Lowered levels of macular pigmentation are a causitive factor in the development of macular degeneration.

Macular pigment in henle fiber membranes:A model for Haidinger's brushes

The dichroic properties of lutein, presumed to be the macular pigment, are demonstrated and the structure of Henle fiber membranes is discussed. A consequence of the pigment molecules being incorporated into the bilipid components of these membranes is shown to be the production of Haidingers brushes. Spectra of lutein in association with phospholipid model membranes at different temperatures are presented and these support the theory that such incorporation occurs. Additional experiments test an alternative model for Haidingers brushes and show it to be inconsistent with the spectroscopic properties of lutein.

Macular pigment response to a supplement containing meso-zeaxanthin, lutein and zeaxanthin

BackgroundAge-related macular degeneration (AMD) is a disease with multiple risk factors, many of which appear to involve oxidative stress. Macular pigment, with its antioxidant and light-screening properties, is thought to be protective against AMD. A result has been the appearance of dietary supplements containing the macular carotenoids, lutein and zeaxanthin. More recently, a supplement has been marketed containing, in addition, the third major carotenoid of the macular pigment, meso-zeaxanthin. The purpose of the study was to determine the effectiveness of such a supplement in raising macular pigment density in human subjects.MethodsA 120 day supplementation study was conducted in which 10 subjects were given gel-caps that provided 20 mg/day of predominantly meso-zeaxanthin, with smaller amounts of lutein and zeaxanthin. A second group of 9 subjects were given gel caps containing a placebo for the same 120 day period. Prior to and during the supplementation period, blood serum samples were analyzed by high performance liquid chromatography for carotenoid content. Similarly, macular pigment optical density was measured by heterochromatic flicker photometry. Differences in response between the supplementation and placebo groups were tested for significance using a students t-test.ResultsDuring supplementation with the carotenoids, blood samples revealed the presence of all three carotenoids. Macular pigment optical density, measured at 460 nm, rose at an average rate of 0.59 ± 0.79 milli-absorbance unit/day in the 10 supplemented subjects. This was significantly different from the placebo group (9 subjects) for whom the average rate was -0.17 ± 0.42 milli-absorbance units/day.ConclusionWe have shown for the first time that meso-zeaxanthin is absorbed into the serum following ingestion. The data indicate that a supplement containing predominantly meso-zeaxanthin is generally effective at raising macular pigment density, and may turn out to be a useful addition to the defenses against AMD.

Dose-dependent response of serum lutein and macular pigment optical density to supplementation with lutein esters.

We conducted a study to determine the effect of different doses of a lutein supplement on serum lutein concentration and macular pigment optical density (MPOD). Lutein is one of the major components of human macular pigment. Eighty-seven subjects received daily doses of 5, 10, or 20 mg of lutein, or a placebo, over a 140 day period. Serum lutein concentration was determined by HPLC and MPOD by heterochromatic flicker photometry (HFP). Serum lutein responded positively, except in the placebo group, reaching a plateau that, averaged for each dosage group, was linearly dependent on dose. Likewise MPOD, on average, increased at a rate that varied linearly with dose. For subjects deemed more proficient at HFP, approximately 29% of the variability in MPOD response could be attributed to a linear dependence on the fractional change in serum lutein concentration. We did not detect any significant influence of age on serum lutein uptake or MPOD response.

Carotenoids : Physical, Chemical, and Biological Functions and Properties

THE STRUCTURAL PROPERTIES, CHARACTERISTICS, AND INTERACTIONS OF CAROTENOIDS The Orange Carotenoid Protein of Cyanobacteria, C. A. Kerfeld, M. Alexandre, and D.Kirilovsky Carotenoids in Lipid Membranes, W.I. Gruszecki Hydrophilic Carotenoids: Carotenoid Aggregates, H-R Sliwka, Vassilia Partali, and S.F. Lockwood ANALYTICAL METHODOLOGIES FOR THE MEASUREMENT OF CAROTENOIDS The Use of NMR Detection of LC in Carotenoid Analysis, K.Holtin and K. Albert Quantitative Methods for the Determination of Carotenoids in the Retina, R.A. Bone, W. Schalch, and J.T. Landrum Application of Resonance Raman Spectroscopy to the Detection of Carotenoids In Vivo, I.V. Ermakov, M. Sharifzadeh, P.S. Bernstein, and W. Gellermann APPLICATIONS OF SPECTROSCOPIC METHODOLOGIES TO CAROTENOID SYSTEMS Identification of Carotenoids in Photosynthetic Proteins: Xanthophylls of the Light Harvesting Antenna, A.V. Ruban Effects of Self-Assembled Aggregation on Excited States, T. Polivka Applications of EPR Spectroscopy to Understanding Carotenoid Radicals, L.D. Kispert, L. Focsan, and T. Konovalova EPR Spin Labeling in Carotenoid-Membrane Interactions, W. K. Subczynski and J. Widomska CHEMICAL BREAKDOWN OF CAROTENOIDS IN VITRO AND IN VIVO Formation of Carotenoid Oxygenated Cleavage Products, C.Caris-Veyrat Thermal and Photochemical Degradation of Carotenoids, C.D. Borsarelli and A.Z. Mercadante Antioxidant and Photoprotection Functions and Reactions Involving Singlet Oxygen and Reactive Oxygen Species The Functional Role of Xanthophylls in the Primate Retina, W. Schalch, R.A. Bone, and J.T. Landrum Properties of Carotenoid Radicals and Excited States and Their Potential Role in Biological Systems, R. Edge and G. Truscott Carotenoid Uptake and Protection in Cultured RPE, M. Rozanowska and B. Roz The Carotenoids of Macular Pigment and Bisretinoid Lipofuscin Precursors in Photoreceptor Outer Segments, J.R. Sparrow and S.R. Kim CELL CULTURE METHODS APPLIED TO UNDERSTANDING CAROTENOID RECOGNITION AND ACTION Mechanisms of Intestinal Absorption of Carotenoids: Insights from In Vitro Systems, E. H. Harrison Competition Effects on Carotenoid Absorption by Caco- Cells, E. Reboul and P. Borel THE CHEMISTRY AND BIOCHEMISTRY OF CAROTENE OXIDASES, CELL REGULATION, AND CANCER Diverse Activities of Carotenoid Cleavage Oxygenases, E. K. Marasco and C. Schmidt-Dannert Oxidative Metabolites of Lycopene and Their Biological Functions, J.R. Mein and X-D Wang Lycopene Oxidation, Uptake, and Activity in Human Prostate Cell Culture, P.E. Bowen Carotenoids as Modulators of Molecular Pathways Involved in Cell Proliferation and Apoptosis, P. Palozza, A. Catalano, and R. Simone CAROTENOIDS AND CAROTENOID BIOCHEMISTRY IN ANIMAL SYSTEMS Control and Function of Carotenoid Coloration in Birds: Selected Case Studies, K.J. McGraw and J. D. Blount Transport of Carotenoids by a Carotenoid-Binding Protein in the Silkworm, T. Sakudoh and K. Tsuchida Specific Accumulation of Lutein within the Epidermis of Butterfly Larvae, J.T. Landrum, D. Callejas, and F. Alvarez-CalderonAny books that you read, no matter how you got the sentences that have been read from the books, surely they will give you goodness. But, we will show you one of recommendation of the book that you need to read. This carotenoids physical chemical and biological functions and properties is what we surely mean. We will show you the reasonable reasons why you need to read this book. This book is a kind of precious book written by an experienced author.

ANALYSIS OF ZEAXANTHIN DISTRIBUTION WITHIN INDIVIDUAL HUMAN RETINAS

Publisher Summary This chapter discusses the analysis of zeaxanthin distribution within individual human retinas. In this analysis, sections of individual eyes are analyzed for the content of the three stereoisomers of zeaxanthin, thereby determining their distribution across the retina. Retina contains two isomeric xanthophylls—lutein arid zeaxanthin—with the greatest concentration at the center of the macula and diminishing with eccentricity. The elution order of the three authentic zeaxanthin dicarbamate diastereomer in a racemic mixture is prepared from rhodoxanthin. An analysis of serum zeaxanthin reveals that the serum contains dominantly RR-zeaxanthin. The principal peak was collected and combined with a sample of the racemic mixture. The results and observations support the hypothesis that lutein and/or zeaxanthin undergoes oxidation in the retina followed by nonstereospecific reduction to regenerate the observed suite of stereoisomers. The presence and distribution of these stereoisomers appear to be consistent with, and support, a hypothesis of antioxidant function for the macular carotenoids.

Distribution of macular pigment components, zeaxanthin and lutein, in human retina.

Publisher Summary This chapter discusses the distribution of macular pigment components in human retina. The isomeric dihydroxycarotenoids, zeaxanthin and lutein have been identified as the major constituents of the macular pigment of the human retina. Although these pigments appear to be localized in a small area centered on the fovea, high-performance liquid chromatography (HPLC) has revealed their presence throughout the neural retina. This technique is also sufficiently sensitive to quantify the pigments in neonatal and prenatal eyes. In addition, an alternative approach to determining the distribution of macular pigment carotenoids in the retina is through microspectrophotometry of fixed retinal tissue. Beyond the immediate yellow spot, however, the pigment density appears to be too low for accurate quantitation by this technique. The distribution of individual zeaxanthin diastereoisomers throughout the retina is not known but is currently under investigation. In the macular region, the average ratio of zeaxanthin to mzeaxanthin is found to range from 1.08 to 1.34 to 1.

Linear dichroism and orientational studies of carotenoid Langmuir-Blodgett films

Abstract The linear dichroism of single monolayers of lutein, zeaxanthin and a mixture of lutein and synthetic phosphatidylcholine has been measured. The angle of orientation of the carotenoid molecules was found to lie between 45° and 51° relative to the plane of the solid support. Although the adsorbed monolayers were mostly in a monomeric state, microscopic observations, as well as the II-A isotherms, indicated the existence of crystalline islets. The results have been interpreted in connection with Haidingers polarization brushes.

The heats of hydrogenation of the metal-metal bonded complexes [M(CO)3C5H5]2 (M = Cr, Mo, W)

Abstract Direct measurement of the enthalpy of decomposition of HCr(CO) 3 C 5 H 5 to [Cr(CO) 3 C 5 H 5 ] 2 and H 2 was made by differential scanning calorimetry. The heat of hydrogenation of 1,3-cyclohexadiene by HM(CO) 3 C 5 H 5 for M = Cr, Mo, and W was measured by solution calorimetry. The enthalpies of iodination of [M(CO) 3 C 5 H 5 ] 2 and HM(CO) 3 C 5 H 5 were measured for M = Mo and W. These data have been used to calculate the heats of hydrogenation for each of the metal—metal bonded dimers, [M(CO) 3 C 5 H 5 ] 2 (M = Cr, Mo, and W). C 5 H 5 (CO) 3 M-M(CO) 3 C 5 H 5 (s) + H 2 (g) → 2HM(CO) 3 C 5 H 5 (s) Addition of hydrogen has been found to be exothermic for M = Cr, W (−3.3 kcal/mol and −1.5 kcal/mole, respectively) but endothermic for M = Mo (+6.3 kcal/mol). These results are consistent with the trend of increasing MH bond strengths upon descending Group VI. Addition of H 2 to [Cr(CO) 3 C 5 H 5 ] 2 is favored by the unusually weak chromium—chromium bond.