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Inhibitory Effect of Avenanthramides (Avn) on Tyrosinase Activity and Melanogenesis in α-MSH-Activated SK-MEL-2 Cells: In Vitro and In Silico Analysis. Int J Mol Sci 2021; 22:ijms22157814. [PMID: 34360580 PMCID: PMC8345984 DOI: 10.3390/ijms22157814] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/12/2021] [Accepted: 07/16/2021] [Indexed: 11/22/2022] Open
Abstract
Melanin causes melasma, freckles, age spots, and chloasma. Anti-melanogenic agents can prevent disease-related hyperpigmentation. In the present study, the dose-dependent tyrosinase inhibitory activity of Avenanthramide (Avn)-A-B-C was demonstrated, and 100 µM Avn-A-B-C produced the strongest competitive inhibition against inter-cellular tyrosinase and melanin synthesis. Avn-A-B-C inhibits the expression of melanogenesis-related proteins, such as TRP1 and 2. Molecular docking simulation revealed that AvnC (−7.6 kcal/mol) had a higher binding affinity for tyrosinase than AvnA (−7.3 kcal/mol) and AvnB (−6.8 kcal/mol). AvnC was predicted to interact with tyrosinase through two hydrogen bonds at Ser360 (distance: 2.7 Å) and Asn364 (distance: 2.6 Å). In addition, AvnB and AvnC were predicted to be skin non-sensitizers in mammals by the Derek Nexus Quantitative Structure–Activity Relationship system.
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ElObeid AS, Haseeb A. Treating ENT symptoms and diseases induced by extraesophageal acidity using plant extracted melanin. Med Hypotheses 2020; 144:110126. [PMID: 32758902 DOI: 10.1016/j.mehy.2020.110126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 07/18/2020] [Indexed: 10/23/2022]
Affiliation(s)
| | - Adil Haseeb
- Department of Physics, Faculty of Science, University of Khartoum, Sudan
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ElObeid AS, Kamal-Eldin A, Abdelhalim MAK, Haseeb AM. Pharmacological Properties of Melanin and its Function in Health. Basic Clin Pharmacol Toxicol 2017; 120:515-522. [PMID: 28027430 DOI: 10.1111/bcpt.12748] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/14/2016] [Indexed: 01/08/2023]
Abstract
The biological pigment melanin is present in most of the biological systems. It manifests a host of biological and pharmacological properties. Its role as a molecule with special properties and functions affecting general health, including photoprotective and immunological action, are well recognized. Its antioxidant, anti-inflammatory, immunomodulatory, radioprotective, hepatic, gastrointestinal and hypoglycaemic benefits have only recently been recognized and studied. It is also associated with certain disorders of the nervous system. In this MiniReview, we consider the steadily increasing literature on the bioavailability and functional activity of melanin. Published literature shows that melanin may play a number of possible pharmacological effects such as protective, stimulatory, diagnostic and curative roles in human health. In this MiniReview, possible health roles and pharmacological effects are considered.
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Affiliation(s)
- Adila Salih ElObeid
- King Abdullah International Medical Research Centre, National Guard & Health Affairs, Riyadh, Saudi Arabia
| | - Afaf Kamal-Eldin
- Department of Food Science, United Arab Emirates University, AlAin, United Arab Emirates
| | | | - Adil M Haseeb
- Physics and Astronomy Department, King Saud University, Riyadh, Saudi Arabia
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Zhang P, Yue Y, Pan D, Yang R, Xu Y, Wang L, Yan J, Li X, Yang M. Pharmacokinetics study of Zr-89-labeled melanin nanoparticle in iron-overload mice. Nucl Med Biol 2016; 43:529-533. [DOI: 10.1016/j.nucmedbio.2016.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/24/2016] [Accepted: 05/28/2016] [Indexed: 10/21/2022]
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Kim YJ, Khetan A, Wu W, Chun SE, Viswanathan V, Whitacre JF, Bettinger CJ. Evidence of Porphyrin-Like Structures in Natural Melanin Pigments Using Electrochemical Fingerprinting. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:3173-3180. [PMID: 26924536 DOI: 10.1002/adma.201504650] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 01/13/2016] [Indexed: 06/05/2023]
Abstract
Eumelanins are extended heterogeneous biopolymers composed of molecular subunits with ambiguous macromolecular topology. Here, an electrochemical fingerprinting technique is described, which suggests that natural eumelanin pigments contain indole-based tetramers that are arranged into porphyrin-like domains. Spectroscopy and density functional theory calculations suggest that sodium ions undergo occupancy-dependent stepwise insertion into the core of porphyrin-like tetramers in natural eumelanins at discrete potentials.
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Affiliation(s)
- Young Jo Kim
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Abhishek Khetan
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
- Institute for Combustion Technology, RWTH, Aachen, 52062, Germany
| | - Wei Wu
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Sang-Eun Chun
- Department of Chemistry, University of Oregon, Eugene, OR, 97403, USA
| | | | - Jay F Whitacre
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Christopher J Bettinger
- Department of Materials Science and Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
- McGowan Institute of Regenerative Medicine, 450 Technology Drive, Suite 300, Pittsburgh, PA, 15219, USA
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Araújo M, Viveiros R, Correia TR, Correia IJ, Bonifácio VD, Casimiro T, Aguiar-Ricardo A. Natural melanin: A potential pH-responsive drug release device. Int J Pharm 2014; 469:140-5. [DOI: 10.1016/j.ijpharm.2014.04.051] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 04/17/2014] [Accepted: 04/19/2014] [Indexed: 01/20/2023]
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Willis GL. Parkinson's disease as a neuroendocrine disorder of circadian function: dopamine-melatonin imbalance and the visual system in the genesis and progression of the degenerative process. Rev Neurosci 2009; 19:245-316. [PMID: 19145986 DOI: 10.1515/revneuro.2008.19.4-5.245] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
For more than 50 years, Parkinson's disease (PD) has been conceptualized as a product of nigro-striatal dopamine (NSD) system degeneration. In spite of a growing body of evidence depicting the mammalian brain as an interrelated complexity of circuitous systems, dopamine (DA) deficiency of the NSD is still regarded as the main problem, with DA replacement being the purpose of therapeutic intervention. For at least 191 years circadian involvement in various aspects of PD, including depression and insomnia, has been recognized as an integral part of the symptom matrix of PD and yet attempts to elucidate the involvement of this system is uncharted territory. The present review attempts a major reorganization of mammalian brain into a coordinated complex involving the NSD and the retinal hypothalamic tract (RHT) as the primary systems involved in the retino-diencephalic/mesencephalic-pineal (RDMP) axis. Secondary systems including the lateral hypothalamus (LH), the area postraema (AP) and the subthalamic nucleus (STN) also form an integral part of this system as they have been shown to be either intimately related to the primary systems of the RDMP axis or have been shown to be significantly involved in the expression and treatment of PD. A large volume of evidence suggests that the RDMP axis is activated during the course of PD and during therapeutic intervention. Four types of neurotoxicity associated with melatonin are identified and the susceptibility of various parts of the RDMP axis to undergo neuropathological change, the tendency for melatonin to induce PD-like behavioural toxicity, and the relationship of this to PD symptomotology are described. This includes adverse effects of melatonin on motor function, hypotension, the adjuvant use of benzodiazepines, depression, insomnia, body weight regulation and various biochemical effects of melatonin administration: all problems currently facing the proposal to introduce melatonin as an adjuvant. It is suggested further that traditional DA replacement may well work by exerting its effect upon the circadian system, rather than simply replacing deficient DA. Activation of the circadian function by antagonizing melatonin with bright light not only has therapeutic value in treating the primary symptoms of PD but it shares a common mechanism with L-dopa in reducing the occurrence of seborrheic dermatitis. Concepts at the centre of understanding pineal function in PD, including pineal calcification, melatonin deficiency, symptomatic versus protective features of melatonin and antioxidative effects, are explained in a counterintuitive context. Intriguing propositions including the role of the retina in the aetiology of PD and that the nigra functions as a retina in this disorder are presented with the intention to provide a new understanding of the underlying compromised function in PD and to provide new treatment strategies. For the first time, abundant evidence is presented describing PD as an endocrine disorder of melatonin hyperplasia. The role of circadian interventive therapies and internal desynchrony in the aetiology and progression of PD provides a new direction for understanding the underlying physiology of a disease which is currently in a state of impasse and provides new hope for those who suffer from its debilitating effects.
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Affiliation(s)
- Gregory L Willis
- The Bronowski Institute of Behavioural Neuroscience, Neurosciences Section, Coliban Medical Centre, Kyneton, Victoria, Australia.
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Moses DN, Harreld JH, Stucky GD, Waite JH. Melanin and Glycera jaws: emerging dark side of a robust biocomposite structure. J Biol Chem 2006; 281:34826-32. [PMID: 16984906 DOI: 10.1074/jbc.m603429200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Defining the design principles guiding the fabrication of superior biocomposite structures from an assemblage of ordinary molecules is a key goal of biomimetics. Considering their low degree of mineralization, Glycera jaws have been shown to be extraordinarily resistant to abrasion based on the metric hardness3/Young's modulus2. The jaws also exhibit an impressive chemical inertness withstanding boiling concentrated hydrochloric acid as well as boiling concentrated sodium hydroxide. A major organic component largely responsible for the chemical inertness of the jaws has been characterized using a spectrophotometric assay for melanin content, 13C solid state nuclear magnetic resonance, IR spectroscopy, and laser desorption ionization-time of flight mass spectrometry and is identified here as a melanin-like network. Although melanin is widely distributed as a pigment in tissues and other structural biomaterials, to our knowledge, Glycera jaws represent the first known integument to exploit melanin as a cohesive load- and shape-bearing material.
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Affiliation(s)
- Dana N Moses
- Program of Biomolecular Science and Engineering, Department of Chemistry and Biochemistry, University of California, Santa Barbara 93106, USA.
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Eibl O, Schultheiss S, Blitgen-Heinecke P, Schraermeyer U. Quantitative chemical analysis of ocular melanosomes in the TEM. Micron 2006; 37:262-76. [PMID: 16364648 DOI: 10.1016/j.micron.2005.08.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 08/25/2005] [Accepted: 08/25/2005] [Indexed: 11/20/2022]
Abstract
Melanosomes in retinal tissues of a human, monkey and rat were analyzed by EDX in the TEM. Samples were prepared by ultramicrotomy at different thicknesses. The material was mounted on Al grids and samples were analyzed in a Zeiss 912 TEM equipped with an Omega filter and EDX detector with ultrathin window. Melanosomes consist of C and O as main components, mole fractions are about 90 and 3-10 at.%, respectively, and small mole fraction ratios, between 2 and 0.1 at.%, of Na, Mg, K, Si, P, S, Cl, Ca. All elements were measured quantitatively by standardless EDX with high precision. Mole fractions of transition metals Fe, Cu and Zn were also measured. For Fe a mole fraction ratio of less than 0.1at.% was found and gives the melanin its paramagnetic properties. Its mole fraction is however close to or below the minimum detectable mass fraction of the used equipment. Only in the human eye and only in the retinal pigment epitelium (rpe) the mole fractions of Zn (0.1 at.% or 5000 microg/g) and Cu were clearly beyond the minimum detectable mass fraction. In the rat and monkey eye the mole fraction of Zn was at or below the minimum detectable mass fraction and could not be measured quantitatively. The obtained results yielded the chemical composition of the melanosomes in the choroidal tissue and the retinal pigment epitelium (rpe) of the three different species. The results of the chemical analysis are discussed by mole fraction correlation diagrams. Similarities and differences between the different species are outlined. Correlation behavior was found to hold over species, e.g. the Ca-O correlation. It indicates that Ca is bound to oxygen rich sites in the melanin. These are the first quantitative analyses of melanosomes by EDX reported so far. The quantitative chemical analysis should open a deeper understanding of the metabolic processes in the eye that are of central importance for the understanding of a large number of eye-related diseases. The chemical analysis also allows a correlation with structural changes observed at the various regions of the eye.
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Affiliation(s)
- O Eibl
- Insutitut für Angewandte Physik, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
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Hung YC, Sava VM, Blagodarsky VA, Hong MY, Huang GS. Protection of tea melanin on hydrazine-induced liver injury. Life Sci 2003; 72:1061-71. [PMID: 12495784 DOI: 10.1016/s0024-3205(02)02348-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The protective activity of melanin derived from tea (MDFT) was studied using hydrazine as a DNA-reactive chemical agent. Intra-peritoneal administration of MDFT at the doses of 5 or 20 mg/kg dose-dependently prevented liver toxicity induced by hydrazine in rats. It normalized rises in serum alanine transferase activity and a decrease in the glutathione level in the liver. It also reduced the hepatic malondialdehyde concentration. Monitoring the intensity of chemiluminescence showed that MDFT could prevent the production of free radicals that are generated owing to metabolic transformation of hydrazine. It also prevented the formation 8-hydroxy-deoxyguanosine (8-OH-dG) DNA adducts. The results obtained in vivo and in vitro suggest that MDFT confers marked protection of the liver against hydrazine-induced oxidative toxicity.
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Affiliation(s)
- Y C Hung
- Section of Gynecologic Oncology, Department of Obstetrics and Gynecology, China Medical College, 91 Hsueh Shih Road, Taichung 404, Taiwan, ROC
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Sava V, Hung Y, Blagodarsky V, Hong MY, Huang G. The liver-protecting activity of melanin-like pigment derived from black tea. Food Res Int 2003. [DOI: 10.1016/s0963-9969(02)00199-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Hung YC, Sava VM, Makan SY, Chen THJ, Hong MY, Huang GS. Antioxidant activity of melanins derived from tea: comparison between different oxidative states. Food Chem 2002. [DOI: 10.1016/s0308-8146(01)00403-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Sava V, Hung Y, Golkin B, Hong MY, Huang G. Protective activity of melanin-like pigment derived from tea on Drosophila melasnogaster against the toxic effects of benzidine. Food Res Int 2002. [DOI: 10.1016/s0963-9969(01)00163-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Samuelson D, Lewis P, MacKay E, Whitley R. The influence of aging and low zinc nutrition on the choroid in the pig: II. The melanosome. Vet Ophthalmol 2001; 2:35-45. [PMID: 11397241 DOI: 10.1046/j.1463-5224.1999.00044.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of low zinc nutrition and aging on central choroidal melanosomes were examined in the pig. Melanosomes of central choroidal melanocytes were morphologically and morphometrically examined in three populations of pigs (young, pregnant and aged), that were maintained on either control (C) or low zinc (LZ) diets. In C groups, the typical melanosomes decreased in size with age, although a subpopulation of larger melanosomes occurred in the oldest group. In contrast, the melanosomes of the animals on LZ diets increased in size significantly in the adult groups. The melanosomes in the pregnant and aged groups were 65% and 30-40% greater than those of the age-matched C groups. Extremely large melanosomes were frequently encountered in adult LZ choroidal melanocytes. Melanogenesis of these large bodies included the formation of one or more outer shells. Fusion of adjacent large melanosomes was also observed. Melanolysosomal-like bodies were observed, particularly among the pigmented cells in the large blood vessel region of C and LZ adults. Melanin dynamics, i.e. its production and breakdown, occurred within choroidal melanocytes throughout much of the lifespan of the pig. This dynamic was greatly influenced by low zinc nutrition, resulting in unusual and aberrant melanin activity.
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Affiliation(s)
- D.A. Samuelson
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, USA; Department of Small Animal Clinical Surgery, Auburn University, Auburn, AL, USA
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Sava VM, Galkin BN, Hong MY, Yang PC, Huang GS. A novel melanin-like pigment derived from black tea leaves with immuno-stimulating activity. Food Res Int 2001. [DOI: 10.1016/s0963-9969(00)00173-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Geng L, Wihlmark U, Algvere PV. Lipofuscin accumulation in iris pigment epithelial cells exposed to photoreceptor outer segments. Exp Eye Res 1999; 69:539-46. [PMID: 10548474 DOI: 10.1006/exer.1999.0735] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lipofuscin accumulates in retinal pigment epithelial (RPE) cells with increasing age in response to phagocytotic degradation of worn-out disks of photoreceptor outer segments (POS). This study investigates the ability of iris pigment epithelial (IPE) cells to ingest POS and compares the phagocytotic capacity of RPE and IPE cells by measuring their amounts of lipofuscin-specific autofluorescence.IPE and RPE cells were isolated from the same calf eyes. After growing to confluence, primary cultures from 15 eyes (69 wells) were exposed to bovine POS daily, or kept as controls. After 1, 2 and 3 weeks, respectively, the cellular amounts of lipofuscin were quantified by a computerized static cytofluorometer system (Nikon Microphot SA with a Nikon p102 photometer). Lipofuscin-specific fluorescence (550 nm barrier filter eliminating nonspecific autofluorescence) of 100 randomly selected individual cells from each well was measured. Electron microscopy revealed phagosomes (containing POS disk membranes) and lipofuscin-like inclusions in the cytoplasm of RPE and IPE cells. In both IPE and RPE cultures, the POS-challenged cells had significantly higher (P<0. 01) lipofuscin-specific fluorescence than the control cells. The fluorescence levels were higher in POS-challenged RPE cells as compared to IPE cells after 1 (P< 0.001), 2 (P<0.01) and 3 (P<0.001) weeks, respectively. The fluorescence level of POS-fed IPE cells at 3 weeks was 56% of that of RPE cells.IPE cells have the ability to phagocytose POS, resulting in an accumulation of lipofuscin intracellularly. The amount of lipofuscin was lower in IPE cells compared to RPE cells, probably reflecting the lower phagocytotic capacity of IPE.
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Affiliation(s)
- L Geng
- Departments of Ophthalmology and Pathology II, University of Linköping, Linköping, SE-, 581 85, Sweden
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Willis GL, Armstrong SM. Orphan neurones and amine excess: the functional neuropathology of Parkinsonism and neuropsychiatric disease. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1998; 27:177-242. [PMID: 9729369 DOI: 10.1016/s0165-0173(98)00013-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The aetiology and treatment of Parkinsonism is currently conceptualised within a dopamine (DA) deficiency-repletion framework. Loss of striatal DA is thought to cause motor impairment of which tremor, bradykinaesia and rigidity are prominent features. Repletion of deficient DA should at least minimise parkinsonian signs and symptoms. In Section 2, based on extensive pre-clinical and clinical findings, the instability of this approach to Parkinsonism is scrutinised as the existing negative findings challenging the DA deficiency hypothesis are reviewed and reinterpreted. In Section 3 it is suggested that Parkinsonism is due to a DA excess far from the striatum in the area of the posterior lateral hypothalamus (PLH) and the substantia nigra (SN). This unique area, around the diencephalon/mesencephalon border (DCMCB), is packed with many ascending and descending fibres which undergo functional transformation during degeneration, collectively labelled 'orphan neurones'. These malformed cells remain functional resulting in pathological release of transmitter and perpetual neurotoxicity. Orphan neurone formation is commonly observed in the PLH of animals and in man exhibiting Parkinsonism. The mechanism by which orphan neurones impair motor function is analogous to that seen in the diseased human heart. From this perspective, to conceptualise orphan neurones at the DCMCB as 'Time bombs in the brain' is neither fanciful nor unrealistic [E.M. Stricker, M.J. Zigmond, Comments on effects of nigro-striatal dopamine lesions, Appetite 5 (1984) 266-267] as the DA excess phenomenon demands a different therapeutic approach for the management of Parkinsonism. In Section 4 the focus is on this novel concept of treatment strategies by concentrating on non-invasive, pharmacological and surgical modification of functional orphan neurones as they affect adjacent systems. The Orphan neurone/DA excess hypothesis permits a more comprehensive and defendable interpretation of the interrelationship between Parkinsonism and schizophrenia and other related disorders.
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Affiliation(s)
- G L Willis
- The Bronowski Institute of Behavioural Neuroscience, Coliban Medical Centre, Kyneton, Victoria 3444, Australia
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Barrenas ML. Hair Cell Loss from Acoustic Trauma in Chloroquine-treated Red, Black and Albino Guinea Pigs. Int J Audiol 1997. [DOI: 10.3109/00206099709071973] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Masuda M, Yamazaki K, Toyama Y, Kanzaki J, Hosoda Y. Ultrastructural recognition of gap junctions between melanocytes in human vestibular organs by tannic acid containing fixative preparation and freeze-fracture technique. Anat Rec (Hoboken) 1996; 246:8-14. [PMID: 8876819 DOI: 10.1002/(sici)1097-0185(199609)246:1<8::aid-ar2>3.0.co;2-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND The purpose of the present study was to obtain additional information about the ultrastructural characteristics of gap junctions between melanocytes in human vestibular organs by using various ultrastructural techniques. METHODS All materials were obtained from patients with vestibular schwannoma. Glutaraldehyde-fixed specimens and specimens treated with fixative containing glutaraldehyde and tannic acid were processed for conventional ultrathin transmission electron microscopic (TEM) examination. Others were prepared for freeze-fracture replica and examined by TEM. RESULTS Gap junctions were present between adjacent subepithelial melanocytes. The gaps between the inner leaflets of the apposed plasma membranes at the gap junctions were 10-12 nm, and the gaps between the outer leaflets were 2-4 nm. The intercellular space between the apposed plasma membranes of gap junctions showed the deposition of high electron-dense material in specimens prepared with fixative containing glutaraldehyde and tannic acid. At the highest magnification specimens fixed by glutaraldehyde with or without tannic acid and cut obliquely to the plasma membranes showed periodic substructures with constant repeating lattices or a small porous structure at the junctions. Study by freeze fracture revealed that these gap junctions between melanocytes consisted of 100-200 aggregations of connexon particles that were approximately 8.8 nm in diameter. CONCLUSIONS We suggest that melanocytes may construct a cellular network involved in the maintenance of the homeostasis of human vestibular organs through the intimate transmission of various signals or intercellular informations via well-developed gap junctions.
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Affiliation(s)
- M Masuda
- Department of Otorhinolaryngology, Keio University, School of Medicine, Tokyo, Japan
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Abstract
Ultrastructural features of the retinal pigment epithelium and photoreceptor cells were studied in vitiligo (C57BL/6 mivit/mivit) mice. Eyes from 12-day- to 56-week-old animals were analysed. Abnormal photoreceptors were seen in 12-day-old mice. By 3 weeks malformed outer segments were evident in the posterior and equatorial retina, but normal photoreceptors were present in the periphery. By 28 weeks, a marked gradient in cell loss was evident, with a progressive increase in cell viability along the posterior-peripheral axis. Viable intact photoreceptors were still present in the peripheral retina of 56-week-old mice. Melanosome content varied between adjacent pigment epithelium cells in both the posterior and peripheral retina. In the choroid, however, a steep posterior-peripheral gradient in melanosome content was evident with highest pigmentation in the periphery. In the optic nerve head region abnormal development of photoreceptors was correlated with proliferation of abnormal pigment epithelium cells. Accumulation of rod outer segment debris in the posterior and peripheral subretinal space preceded photoreceptor cell death. Short pigment epithelial microvilli without proper attachment to photoreceptors are suggestive of alterations in pigment-epithelium-photoreceptor interaction, which might affect photoreceptor differentiation and phagocytosis of rod outer segments by pigment epithelium cells.
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Affiliation(s)
- I Nir
- Department of Pathology, University of Texas Health Science Center, San Antonio 78284-7750, USA
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Masuda M, Yamazaki K, Kanzaki J, Hosoda Y. Ultrastructural evidence of cell communication between epithelial dark cells and melanocytes in vestibular organs of the human inner ear. Anat Rec (Hoboken) 1995; 242:267-77. [PMID: 7668412 DOI: 10.1002/ar.1092420217] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND The possibility of interaction between epithelial dark cells and melanocytes in the mammalian inner ear has been pointed out because of their morphological and biochemical characteristics, although very few studies have dealt directly with communication between these two types of cells. We investigated the dark cell area of human vestibular organs in order to clarify the ultrastructural evidence for cell interaction between epithelial dark cells and melanocytes. METHODS All of the material was obtained from vestibular schwannoma operations. Paraffin sections were stained with hematoxylin and eosin (H&E) and by the Fontana-Masson technique. Other paraffin sections were also stained immunohistochemically for S-100 protein. Glutaraldehyde fixed specimens were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS Light microscopy revealed melanin pigment granules in the cytoplasm of epithelial dark cells. Melanocytes in the subepithelial layer stained positively for S-100 protein. The presence of intraepithelial melanocytes was confirmed by the presence of cell profiles with a large number of melanin pigment granules and S-100 protein in the cytoplasm. SEM showed that the dark cells had a pentagonal surface with microvilli on the apical surface edge. They had complicated structures at the basal portion of their cytoplasm. Melanocytes extending cytoplasmic processes to adjacent areas were observed under the dark cells. TEM showed that the dark cells were tightly linked by junctional complexes in the upper lateral portion of their cytoplasmic membrane and interdigitated by lateral infoldings. Compound melanosomes (phagosomes or secondary lysosomes) found in the cytoplasm of the dark cells contained poorly pigmented melanosomes with a periodic internal structure. Gap junctions were clearly showed between adjacent melanocytes in the subepithelial layer. CONCLUSIONS The characteristic substructures of dark cells and melanocytes suggested the presence of intimate cell interaction between these two types of cells in the vestibular organs of the human inner ear, although it is not clear at this stage whether such cell interaction is specific only for patients with vestibular schwannoma. Dark cells and melanocytes form a cell community that serves to maintain homeostasis in vestibular organs through communication in which cell information obtained by both dark cells and melanocytes serves to facilitate the system.
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Affiliation(s)
- M Masuda
- Department of Otorhinolaryngology, Keio University School of Medicine, Tokyo, Japan
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Dielectric and electric properties of synthetic melanin: the effect of europium ions. J Biol Phys 1995. [DOI: 10.1007/bf00701009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Masuda M, Yamazaki K, Kanzaki J, Hosoda Y. Ultrastructure of melanocytes in the dark cell area of human vestibular organs: functional implications of gap junctions, isolated cilia, and annulate lamellae. Anat Rec (Hoboken) 1994; 240:481-91. [PMID: 7879900 DOI: 10.1002/ar.1092400406] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND It is known that melanocytes exist in almost all parts of the inner ear, such as the cochlear duct, stria vascularis, Reissner's membrane, modiolus, vestibular organs in the region surrounding the cristae and maculae, semicircular canals, and pars rugosa of the endolymphatic sac. But there have been few studies using human materials, because of the difficulty of obtaining materials. We attempted to investigate the detailed ultrastructure of melanocytes in the vestibular organs of human inner ear. METHODS Eight surgical specimens obtained from patients with vestibular schwannoma were studied by light microscopy and electron microscopy. RESULTS Melanocytes were found in the subepithelial layer of the dark cell area. Melanocytes had round or spindle-shaped nuclei and clear cytoplasm with brown pigment granules. Besides melanocytes, there were melanophages, fibroblasts, and small blood vessels. Through electron microscopy we found melanocytes with round-shaped melanosomes in various stages of pigmentation, well-developed Golgi apparatus and endoplasmic reticulum in the cytoplasm, and many cytoplasmic processes. Gap junctions were occasionally found between the cytoplasmic processes. And there were pinocytotic vesicles just under the limiting membrane of melanocytes, and intermediate filaments were abundant in the cytoplasm. Isolated cilia of melanocytes, annulate lamellae, and fusiform banded structures in the connective tissue area around melanocytes were found. CONCLUSIONS Melanocytes in human vestibular organs actively synthesize melanosomes. Frequent findings of isolated cilia and fusiform banded structures and the incidental existence of annulate lamellae may be an indicator of this metabolically activated state of melanocytes. Moreover, monitoring environmental changes by isolated cilia, melanocytes in the human inner ear could act not only as one cell but also as a group to achieve their physiological functions by means of information transmission through gap junctions.
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Affiliation(s)
- M Masuda
- Department of Otorhinolaryngology, Keio University, School of Medicine, Tokyo, Japan
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Holz FG, Piguet B, Minassian DC, Bird AC, Weale RA. Decreasing stromal iris pigmentation as a risk factor for age-related macular degeneration. Am J Ophthalmol 1994; 117:19-23. [PMID: 8291588 DOI: 10.1016/s0002-9394(14)73010-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To evaluate iris color, change of iris color, and iris pigment epithelial defects as risk factors in age-related macular degeneration, we compared 101 patients with age-related macular changes with 102 control subjects in a case-control study. Three of 101 patients (3%) and four of 102 control subjects (4%) had epithelial iris defects. Light iris color during youth was reported by 51 of 101 patients (50.5%) and 42 of 102 control subjects (41.2%) (odds ratio, 1.46; P = .184). Of the 101 patients, 26 (25.7%) noticed their iris color to have become lighter during life compared with six of 102 control subjects (5.9%) (odds ratio, 5.5; P = .0001). At present examination, 63 of 101 patients (62.4%) had light irides compared with 43 of 102 control subjects (42.2%) (odds ratio, 2.27; P = .004). These results suggest that initial light iris color and iris pigment epithelial defects are not associated with an increased risk of age-related macular degeneration, whereas decreased stromal iris pigmentation may indicate a higher risk.
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Affiliation(s)
- F G Holz
- Department of Clinical and Preventive Ophthalmology, Moorfields Eye Hospital, London
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Barrenäs ML. The influence of a melanin-binding drug on temporary threshold shift in humans. SCANDINAVIAN AUDIOLOGY 1994; 23:93-8. [PMID: 8085117 DOI: 10.3109/01050399409047491] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To evaluate the hypothesis that inner-ear melanin protects the sensory cells against harmful noise, noise-induced temporary threshold shift (TTS) was measured in 12 subjects during treatment with the melanin-binding drug, chloroquine, and after cessation of the drug. It was demonstrated that susceptibility to TTS was increased by chloroquine. This increase was most pronounced in young individuals, with dark complexion, and diminished with age. The chloroquine-induced increase in TTS in individuals with a light complexion was small and seemed unaffected by age. It could be argued that patients should avoid noise exposure during treatment with melanin-binding drugs.
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Affiliation(s)
- M L Barrenäs
- Department of Audiology, Sahlgren's Hospital, Göteborg, Sweden
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De Montellano BRO. Melanin, afrocentricity, and pseudoscience. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1993. [DOI: 10.1002/ajpa.1330360604] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
The resonator theory claims that light scattering by the melanin granules of the retinal pigment epithelium causes light to be reflected back through the outer segment of the cones, in a direction opposite that of the incident light. These two opposite directed wave motions may produce standing waves inside the cone outer segment, which then acts as a resonating cavity for light waves. The wavelength specificity of the single cone is determined by the length and the diameter of the cone outer segment. The variation of the length and the diameter of the cone outer segments throughout the retina is then the basis of colour discrimination.
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Affiliation(s)
- N Bülow
- Clinic of Ophthalmology, Copenhagen, Denmark
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Abstract
One factor that influences noise susceptibility is pigmentation. The aim of this study was to investigate the development of melanocytes, other melanin-containing cells and the amount of melanin in stria vascularis from birth to adult age in the gerbil which has a uniform pigmentation of the fur and eyes, is born without hearing but establishes hearing function at 14-18 days after birth. Changes in the melanin morphology, concentration and distribution have been correlated to the development of the inner ear and to the time period during which hearing function is established, which indicates that the melanocytes in stria vascularis are of importance for the hearing function.
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Affiliation(s)
- M L Barrenäs
- Department of Audiology, University of Göteborg, Sahlgren's Hospital, Sweden
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Production of water-soluble phytomelanins. Chem Nat Compd 1991. [DOI: 10.1007/bf00630388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Korochkin L, Saveliev S, Ivanov A, Evgeniev M, Bessova N, Gulimova V. Nerve cells of Drosophila Notch mutant are differentiated inside amphibian brain: a new approach for the analysis of genetic control of nerve cell differentiation. Genetica 1991; 85:23-34. [PMID: 1778472 DOI: 10.1007/bf00056103] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Fragments of the neural primordium of a new Notch mutant of Drosophila melanogaster produced in our laboratory were transplanted into the neural tube of embryos of 4 amphibian species (caudate and ecaudate) immediately after completion of neurulation. The grafts were identified by using a light microscope, scanning electron miscroscope, and in situ hybridization with mobile genetic elements of Drosophila and fluorescent dyes as markers. As has been shown, Drosophila nerve cells survive and differentiate inside the neural tube of amphibian embryos. The grafts increase in size by twentyfold and the cell proliferation zones are retained during the period of six months. Differentiated cells of the graft formed axon-dendritic contacts with recipient cells and penetrated into the organisms' brain structures. The effect of Drosophila transplants proved to be different for caudate and ecaudate amphibians. The presence of the graft accelerated the development of Xenopus laevis and it also affected their behavior. This approach can be very useful for the study of genetic basis of development and behavior.
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Affiliation(s)
- L Korochkin
- Institute of Developmental Biology, Moscow, USSR
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Osak W, Tkacz K, S?awi?ski J, Czternastek H. Dielectric relaxation in synthetic melanin. Biopolymers 1989. [DOI: 10.1002/bip.360281104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Rider MS, Achterberg J. Effect of music-assisted imagery on neutrophils and lymphocytes. BIOFEEDBACK AND SELF-REGULATION 1989; 14:247-57. [PMID: 2597714 DOI: 10.1007/bf01000097] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The purpose of this study was to determine the effects of cell-specific mental imagery on neutrophil and lymphocyte cell counts. Subjects (N = 30) were randomly assigned to one of two experimental groups that underwent a 6-week training program focusing on images of morphology, location, and movement of either neutrophils or lymphocytes. Music was used to enhance the imagery of the subjects. Peripheral white blood cell and differential counts were determined before and after the final 20-minute imagery session. Results indicated that neutrophils decreased significantly (p less than .04) in the neutrophil-change group while lymphocytes did not. The reverse occurred in the lymphocyte-change group, with only the lymphocytes decreasing significantly (p less than .03). The authors concluded that under the conditions of the present study, cell-specific imagery was associated with decreases in peripheral blood cell counts of lymphocytes and neutrophils.
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Affiliation(s)
- M S Rider
- Southern Methodist University, Owens Arts Center, Dallas, Texas 75275
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Menter JM, Willis I. Interaction of several mono- and dihydroxybenzene derivatives of various depigmenting potencies with L-3,4-dihydroxyphenylalanine-melanin. Arch Biochem Biophys 1986; 244:846-56. [PMID: 3080956 DOI: 10.1016/0003-9861(86)90654-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Certain mono- and dihydroxybenzene derivatives cause depigmentation of skin and hair, and appear to be selectively cytotoxic for melanized pigment cells. As direct physical and/or chemical interaction between depigmenter (DP) and pigment melanin may play a role in depigmentation, we have carried out preliminary studies in model systems where such interactions may easily be separated from effects due to tyrosinase, melanosomal proteins, and other components. We have used synthetic L-3,4-hydroxyphenylalanine (L-DOPA)-melanin as a protein-free model pigment and potassium ferricyanide as a model electron acceptor. Compounds studied were catechol, 4-t-butylcatechol, 4-methylcatechol, 3,4-dihydroxyphenylalanine (DOPA), 3,4-dihydroxyphenylacetic acid, hydroquinone, 4-methoxyphenol, 4-t-butylphenol, and 2,6, di-t-butyl-4-methylphenol (BHT) in 0.1 M phosphate buffer, pH 7.4. These compounds vary widely in their ability to depigment hair and skin. Ferricyanide reduction by DP in the presence and absence of melanin was monitored spectrophotometrically. The sparingly soluble BHT and 4-t-butylphenol did not reduce ferricyanide in the absence or presence of melanin. For the other compounds, kinetic analysis demonstrated direct interaction between each DP and melanin. Except for dihydroxyphenylacetic acid, reduction kinetics were consistent with a mechanism involving noninteractive binding of both DP and ferricyanide to melanin prior to coupled electron transfer through the melanin backbone. Kinetic analysis afforded KB, a thermodynamic constant (M-1) for DP-melanin binding, and k', a rate parameter (M s-1) for electron transfer. A dimensionless enhancement factor (EF) was defined as k'KB/ks, with ks a pseudo-first-order constant (s-1) for ferricyanide reduction in the absence of melanin. Depending on the reductant, melanin either retards (EF less than 1) or accelerates (EF greater than 1) the rate of ferricyanide reduction. There appears to be a direct relationship between EF and depigmenting potency. There is no relationship between depigmenting power and the ability per se of the DP to bind to melanin or to reduce ferricyanide.
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Weiter JJ, Delori FC, Wing GL, Fitch KA. Relationship of senile macular degeneration to ocular pigmentation. Am J Ophthalmol 1985; 99:185-7. [PMID: 3970124 DOI: 10.1016/0002-9394(85)90230-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We prospectively evaluated 650 consecutive white patients with senile macular degeneration and compared them to a control group of 363 patients. Ocular pigmentation (iris color and fundus pigmentation) was recorded for each patient, as was hair color (as a child and young adult) and age at evaluation. Patients were from the New England states and Florida. Our most significant finding was that 494 patients with senile macular degeneration (76%) had light-colored irides compared with 145 of the controls (40%). Fundus pigmentation closely corresponded to iris pigmentation (P less than 0.01). Hair color was blond or light brown in 370 of the patients with senile macular degeneration (57%) and in 105 of the controls (29%). Further, there was a tendency for individuals with lightly pigmented irides to have senile macular degeneration at an earlier age than those with dark irides (P less than .01). Thus, increased ocular pigmentation tends to decrease the risk of developing senile macular degeneration.
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Buchanan TA, Gardiner TA, Archer DB. An ultrastructural study of retinal photoreceptor degeneration associated with bronchial carcinoma. Am J Ophthalmol 1984; 97:277-87. [PMID: 6322591 DOI: 10.1016/0002-9394(84)90623-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We studied both eyes of a 66-year-old man with retinal degeneration and oat cell carcinoma of the bronchus. Retinal degeneration was most marked peripheral to the parafovea where photoreceptor cells and their outer segments were absent. Within the parafovea, photoreceptor cells remained but rod outer segments were absent and cone outer segments were fragmented and disorganized. The retinal pigment epithelium contained many immature melanin granules within melanolysosomes, suggesting abnormal melanin synthesis and resorption. We suggest that a pharmacologically active substance resembling a hormone produced by the tumor increased melanin synthesis in the pigment epithelium and that the increased melanin content in these cells compromised their ability to phagocytose and maintain normal turnover of photoreceptor outer segments. We believe these changes led to photoreceptor outer segment loss and subsequent degeneration of the photoreceptor cells.
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