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<html>
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<head><title>Aging Eyes, Infant Eyes, and Excitable Tissues</title></head>
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<body>
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<h1>
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Aging Eyes, Infant Eyes, and Excitable Tissues
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</h1>
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<em>
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<p>
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The eyes and the lungs are sensitive tissues that are easily harmed by inappropriate environmental
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exposure. They are especially sensitive in infancy and old age.
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</p>
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<p>
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For 60 years there have been controversies about the cause of retinopathy of prematurity, which has
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blinded tens of thousands of people.
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</p>
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<p>
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Degeneration of the retina is the main cause of blindness in old people. Retinal injury is caused by
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ordinary light, when the eyes are sensitized by melatonin, prolactin, and polyunsaturated fats. Bright
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light isn't harmful to the retina, even when it is continuous, if the retina isn't sensitized.
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</p>
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<p>
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Melatonin and prolactin are induced by stress, and darkness is a stress because it impairs mitochondrial
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energy production.
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</p>
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<p>
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The polyunsaturated fats which accumulate in the brain and retina damage mitochondria.
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</p>
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<p>
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Iron, which accumulates prenatally, and then again with aging, reacts with unsaturated fats during
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stress to destroy cells.
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</p>
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<p>
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The popular supplements melatonin, tryptophan, fish oils, St. John's wort, and the various omega -3
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oils, all increase the risk of retinal light damage and macular degeneration. Serotonin uptake
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inhibiting antidepressants are suspected to be able to cause it.
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</p>
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<p>
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Processes similar to those that damage the over-sensitized retina can occur in other cells, as a result
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of stress. The substances that sensitize the retina to light-damage, can also increase the incidence of
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new or metastatic cancers.
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</p>
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<p>
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Iron supplements and the use of supplemental oxygen, especially with a vitamin E deficiency exacerbated
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by excessive unsaturated fats in the diet, are still commonly used exactly when they can do the most
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damage.
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</p></em>
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<hr />
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<p>
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One of the recognized achievements of biology has been the demonstration of life"s universality, in the
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sense that organisms of all sorts use the same fundamental genetic code, and that yeasts, lizards, apes, and
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people have remarkably similar cellular systems, as well as a great amount of genetic similarity.
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</p>
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<p>
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There has been another, less well recognized, sort of convergence going on in physiology and
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pathophysiology. Hans Selye"s concept of stress, "the syndrome of being sick," Otto Warburg"s argument that
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a "respiratory defect" was behind all kinds of cancer, and the idea of free radical damage as a common
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factor in disease and aging, helped to create a more general way of looking at the nature of disease that
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superceded medicine"s theories of disease pathogens and genetic mutations, which created thousands of
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"disease entities," none of which had much to do with the individuality of the patient or his environment.
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</p>
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<p>
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The understanding that plants and animals have much biochemistry in common has gradually changed the
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assumptions of the science establishment, which until recently insisted that only "ionizing radiation" could
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affect animals or other organisms that lacked chlorophyll--and insisted that ionizing rays acted only on the
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DNA. Visible light, the textbooks said, was not "chemically active," and so couldn"t possibly affect
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animals" cells. In animals, coloration was seen mainly as decoration and disguise, rather than as a
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functional part of their biochemistry.
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</p>
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<p>
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(Chemically, the meaning of "a pigment" is that it"s a chemical which selectively absorbs radiation. <strong
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>Old observations such as Warburg"s, that visible light can restore the activity of the "respiratory
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pigments," showed without doubt that visible light is biochemically active.
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</strong>By the 1960s, several studies had been published showing the inhibition of respiratory enzymes by
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blue light, and their activation by red light. The problem to be explained is why the science culture simply
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couldn"t accept crucial facts of that sort.)
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</p>
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<p>
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The retina, of course, was allowed (in the views of mainline science) to respond to ordinary light, but the
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few people who studied the biological effects of seasonal or daily cycles of light have until recently
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stayed very close to the nerve pathways leading from the retina to the pineal gland, because those pathways
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could be described in terms of an evolutionarily specialized "third eye." Even with a doctrine of a
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genetically specialized link between the retina and a little of the animal"s physiological chemistry, the
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great, slow-witted science establishment has done its best to avoid thoughts of any deep interaction between
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an organism and its environment, by insisting that the organism runs according to a genetically determined
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"clock" which is located in a few cells in a certain area of the brain, and that nervous impulses from the
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retina have only the small privilege of "setting the clock."
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</p>
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<p>
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It didn"t matter to the academic and medical worlds that a professor, Frank A. Brown, had long ago disproved
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the idea of an innate genetic "clock," because philosophy is much stronger than evidence. Leibniz had said
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that everything in the world runs on its own inner clock, without needing to perceive its surroundings, and
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this idea that everything in the world is a "windowless monad" resonated through the world of science,
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because it justified the pompous authoritarian attitudes of the experts who knew that anything that wasn"t
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already in their heads couldn"t be considered knowledge. <strong>If an organism"s "essence is contained in
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its genes," then it clearly doesn"t interact in any meaningful way with most of its environment.</strong
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> This is the sort of culture that imbued research on the biology of light cycles.
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</p>
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<p>
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When I moved from Mexico, first to Montana and then to Oregon in 1966, I became very conscious of how light
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affects the hormones and the health. (For example, in Montana I experienced an interesting springtime
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shedding of body hair.) Many people who came to cloudy Eugene to study, and who often lived in cheap
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basement apartments, would develop chronic health problems within a few months. Women who had been healthy
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when they arrived would often develop premenstrual syndrome or arthritis or colitis during their first
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winter in Eugene.
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</p>
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<p>
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The absence of bright light would create a progesterone deficiency, and would leave estrogen and prolactin
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unopposed. Beginning in 1966, I started calling the syndrome "winter sickness," but over the next few years,
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because of the prominence of the premenstrual syndrome and fertility problems in these seasonally
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exacerbated disorders, I began calling it the pathology of estrogen dominance. In the endocrinology classes
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I taught at the National College of Naturopathic Medicine, I emphasized the importance of light, and
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suggested that medicine could be reorganized around these estrogen-related processes. If the sparrows of
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Times Square mated in the winter because of the bright lights, it seemed clear that bright artificial light
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would be helpful in regulating human hormones.
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</p>
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<p>
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In our lab at the University of Oregon, our hamsters would try to hibernate, even though they were in
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temperature-controlled laboratories with regular cycles of artificial light. (The ceiling lights provided
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only dim illumination inside their cage boxes, so they were probably in a chronic state of light
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deprivation, which probably increased their sensitivity to the weak environmental cues that Frank Brown had
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investigated, possibly microwaves that easily penetrated the lab walls.) During the winter, when they were
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infertile, I found that their thymus glands practically disappeared. The mechanism seemed to include the
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increase of pineal gland activity (probably increasing melatonin synthesis) in the winter, under the
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intensified activity of the "sympathetic nervous system" (with increased activity of adrenalin and other
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catecholamines), and the melatonin was apparently a signal for suppressing fertility during the stressful
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winter. In some animals (Shvareva and Nevretdinova, 1989), estrogen is increased during hibernation,
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contributing to the reduction of body temperature.
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</p>
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<p>
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In 1994 A.V. Sirotkin found that melatonin inhibits progesterone production but stimulates estrogen
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production, and it"s widely recognized that melatonin generally inhibits the thyroid hormones, creating an
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environment in which fertilization, implantation, and development of the embryo are not possible. This
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combination of high estrogen with low progesterone and low thyroid decreases the resistance of the organism,
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predisposing it to seizures and excitotoxic damage, and causing the thymus gland to atrophy.
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</p>
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<p>
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Cyclical exposure to melatonin can have an effect on the reproductive system opposite to that of chronic
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exposure, and the way exogenous melatonin is delivered to the animal can have unexpected effects on the
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actual amount of melatonin circulating in the blood (Wright and Alves, 2001). The actual amount of melatonin
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in the tissues, its relation to the normal cycling of the animal, and the influence of temperature, are
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often disregarded in melatonin research, making it hard to interpret many of the publications.
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</p>
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<p>
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There is a lot of talk about melatonin"s function as an antioxidant, but, like so many other "antioxidants,"
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melatonin can act as a pro-oxidant at physiologically relevant concentrations<strong>;</strong> some studies
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have found that it, like estrogen, increases the activity of the pro-oxidative free radical nitric oxide
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(which acts like melatonin on pigment cells, causing them to lighten). The promoters of estrogen are also
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making claims that estrogen is a protective antioxidant, though that isn"t true of physiological
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concentrations of estrogen, which can catalyze intense oxidations. The market culture seems to guide most
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research in these substances.
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</p>
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<p>
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Almost any kind of stress increases the formation of melatonin.
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</p>
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<p>
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In some animals, melatonin has been shown to be responsible for whitening of the hair during the winter. In
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some species it acts directly on the pigment cells, but in other species it seems to inhibit the action of
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the melanocyte stimulating hormone.
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</p>
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<p>
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In snowy climates, it"s "ecologically" rational for animals to turn white in the winter, for camouflage. But
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tadpoles also turn white in the dark, or under the influence of melatonin, and the biological meaning of
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that isn"t so clear. It"s possible that being white would reduce their loss of heat through radiation, but I
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think it is more likely that it relates to an increased ability of weak radiation to penetrate their
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tissues, rather than being stopped near the surface by the melanin in the skin. The absence of melanin makes
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them more sensitive to light. Bright light suppresses their melatonin, and makes them turn dark brown or
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black, and this protects them from bright sunlight.
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</p>
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<p>
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In the retina, melatonin increases the sensitivity of the cells to dim light. It, along with prolactin,
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another nocturnal hormone, helps to produce dark adaptation of the eyes.
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</p>
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<p>
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Melatonin increases the concentration of free fatty acids during the night (John, et al., 1983; John and
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George, 1976)), so it"s interesting that one of the long-chain highly unsaturated fatty acids, DHA
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(docosahexaenoic acid), also increases the light sensitivity of the retina.
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</p>
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<p>
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Melatonin lowers body temperature, causes vasoconstriction in the brain, heart, and other organs, and slows
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reactions. An antagonist to melatonin acts as an antidepressant, reducing "behavioral despair" resulting
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from stress. (Dubocovich, et al., 1990.) So, in the behavioral sense, melatonin reduces sensitivity, yet it
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increases the eyes" sensitivity to light, causing them to be injured by light that would otherwise be
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harmless.
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</p>
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<p>
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Since a hibernating animal under the influence of melatonin can become very cold, the light-sensitizing
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function of melatonin is probably related to the biological need to be roused out of the torpor
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occasionally. (Hibernators apparently have to warm up occasionally to sleep in the ordinary manner.)
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Melatonin is said to intensify dreaming, which is part of the process of arousal from sleep.
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</p>
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<p>
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All of the stress-related hormones increase during the night. One of the ways these hormones of darkness act
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is to increase the sensitivity to light, in a process that is an important adaptation for organisms in dim
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light. In the night, our ability to see (and respond to) dim light is increased. But dark-adapted eyes are
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very sensitive to injury by bright light. Light that ordinarily wouldn"t harm the eyes, will do serious
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damage when the eyes are dark adapted.
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</p>
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<p>
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In thinking about the effects of stress and oxygen deprivation, I read the studies demonstrating that the
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formation of the oxygen-wasting age pigment, lipofuscin, is increased by estrogen, by oxygen deprivation (in
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carp living below the ice, or even in fetuses), by metals such as iron, by x-rays, and by highly unsaturated
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fats.
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</p>
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<p>
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Free fatty acids that are mobilized from storage tissues in the night and in the winter also tend to
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increase with aging, as the ability to tolerate stress decreases. Poor circulation and lipofuscin tend to be
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associated, in a vicious cycle. This means that the retina becomes easier to injure by light in old age, for
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some of the same reasons that the infant"s retina is susceptible.
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</p>
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<p>
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The fetus accumulates a very large amount of iron, and it absorbs melatonin from the maternal circulation.
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Prolactin is sometimes elevated in the newborn. Premature babies are often given extra oxygen, which tends
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to cause vasoconstriction by displacing carbon dioxide. Melatonin"s ability to cause vasoconstriction means
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that stress makes supplemental oxygen more toxic. Synthetic glucocorticoids are often given to premature
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babies, adding to the risk of retinal damage.
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</p>
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<p>
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When the mother has been given iron supplements during pregnancy, along with unsaturated oils in the diet,
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the baby is likely to be born with a vitamin E deficiency and suppressed thyroid function, increasing the
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probability that it will be jaundiced, leading to treatment of the jaundice with exposure to very bright
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light.
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</p>
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<p>
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Although Yandell Henderson had already, in 1928, explained the need for carbon dioxide to be used with
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oxygen for resuscitating infants or adults, medical researchers and hospital workers could never accept the
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idea, probably because of a fundamental misunderstanding of the Henderson-Hasselbalch equation. Animal
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experiments show that supplemental oxygen, without carbon dioxide, causes vasoconstriction, reducing the
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tissues" supply of glucose as well as oxygen. In combination with too much light, especially blue light, it
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damages the retina. At hyperbaric pressure, oxygen causes seizures, as well as damage to the lungs and other
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tissues.
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</p>
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<p>
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The contribution of bright light to retinal damage in babies has been denied in several recent publications,
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and these articles undoubtedly provide useful material for defense lawyers to use when hospitals are sued
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for causing blindness. One publication based on experiments with kittens concludes that bright light does
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not harm the newborn"s retina, but the comparison is between continuous light and intermittent light, rather
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than between bright light and dim light. Twelve hours of total darkness, rather than sparing the eye by
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reducing its exposure to light, would sensitize the eye. The only reason such appalling things can be
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published is that their conclusions protect the hospitals.
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</p>
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<p>
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A few good studies of the effect of bright light on the retina, and the fact that dark-skinned people with
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more protective pigment in their eyes have a lower incidence of retinopathy of prematurity, make it clear
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that the ordinary laws of physics and chemistry actually do apply to the infant eye.
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</p>
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<p>
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Light and stress, especially with excess iron, damage the retina when the cells contain too much PUFA, since
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these fats react with light and free radicals. The nocturnal/stress hormones, especially prolactin and
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melatonin, make the retina more sensitive to light, and more easily damaged. (It's too much darkness that
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sets up the problem, since the eyes will adapt to excess light, but darkness increases their sensitivity.)
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</p>
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<p>
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The use of lasers to operate on eyes produces intense inflammation of the eye, but even at low dose the
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diffusing light causes retinal/macular damage.
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</p>
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<p>
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Cytochrome oxidase is one of the enzymes damaged by stress and by blue light, and activated or restored by
|
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red light, thyroid, and progesterone. It's a copper enzyme, so it's likely to be damaged by excess iron. It
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is most active when it is associated with a mitochondrial lipid, cardiolipin, that contains saturated
|
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palmitic acid<strong>;</strong> the substitution of polyunsaturated fats lowers its activity. Mitochonrial
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function in general is poisoned by the unsaturated fats, especially arachidonic acid and DHA.
|
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</p>
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<p>
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Creating a "deficiency" of DHA, even when an oil of known toxicity is used to replace the omega -3 oils,
|
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prevents retinal damage from light. Despite evidence of this sort, Mead Johnson is going ahead with the
|
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marketing of its baby formula containing added DHA which is industrially extracted from algae. (Although the
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researchers who claim that DHA is beneficial haven"t answered my letters, a representative of the company
|
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that manufactures it did answer my question about the actual composition of the oil, and acknowledged that
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they don"t have any idea what the minor ingredients might be.)
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</p>
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<p>
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When animals are made "deficient" in all the exogenous polyunsaturated fatty acids, linoleic and arachidonic
|
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acid as well as linolenic and DHA, they become remarkably resistant to all sorts of stress and toxins.
|
||||
</p>
|
||||
<p>
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The polyunsaturated fats make the lungs more sensitive to excess oxygen or hyperventilation, they make the
|
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eyes more sensitive to light, and they make the brain more sensitive to fatigue.
|
||||
</p>
|
||||
<p>
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The use of synthetic glucocorticoid hormone is standard in treating very premature babies, although it is
|
||||
known to contribute to eye damage. This is because it is considered necessary to improve the lung function
|
||||
of premature babies with respiratory distress. But there is no clear evidence that it is beneficial for lung
|
||||
function in the long run, and very clear evidence that it damages the brain and other organs. There is
|
||||
widespread agreement regarding the use of the glucocorticoids <strong><em>
|
||||
prenatally</em></strong> to accelerate lung development in women who seem likely to deliver
|
||||
prematurely. Natural cortisol is a factor that promotes lung development prenatally. But cortisol is also a
|
||||
signal produced by a stressed fetus, that triggers the birth process. Cortisol, or the synthetic
|
||||
glucocorticoid, inhibits progesterone production, and stimulates estrogen production, activating uterine
|
||||
contractions and other processes that terminate the pregnancy.
|
||||
</p>
|
||||
<p>
|
||||
Apparently, it doesn"t occur to many people that administering the glucocorticoid triggers premature birth,
|
||||
creating the problem they are intending to treat.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Recognizing causal connections between premature birth and respiratory distress and retinopathy of
|
||||
prematurity, it would be obvious that the greatest effort should be made to prevent the problems by
|
||||
improving the health of pregnant women. Hospitals, however, are invested in high technology systems for
|
||||
treating these problems, and even though their results are dismal, they can"t make money by getting pregnant
|
||||
women to eat enough protein to prevent preeclampsia, which is a major cause of premature birth, or by
|
||||
treating the problems with salt, magnesium, progesterone, thyroid, and aspirin when the women haven"t had a
|
||||
good diet.
|
||||
</p>
|
||||
<p>
|
||||
Historically, preeclampsia has been blamed on the mother"s or fetus"s "bad genes," and that cultural bias
|
||||
was the setting in which these high technology prenatal and neonatal systems developed. High technology
|
||||
"neonatology" derives from the same ideology that motivated Josef Mengele"s genetic research in Auschwitz.
|
||||
The idea of genetic determination is still motivating resistance to reasonable preventive approaches.
|
||||
</p>
|
||||
<p>
|
||||
Thyroid, i.e., T3, is very effective in accelerating lung development in the fetus, and it doesn"t have any
|
||||
of the harmful effects of the synthetic glucocorticoids. It normalizes the hormones, increasing progesterone
|
||||
and decreasing estrogen, which are needed for full-term gestation, the opposite of the glucocorticoids"
|
||||
effects. While the cortisol-like drugs damage the brain and other organs, thyroid and progesterone protect
|
||||
them.
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||||
</p>
|
||||
<p>
|
||||
<strong>Old organisms, like newborns, are easily injured by all sorts of inappropriate excitation. As in
|
||||
premature babies, the aged eyes, lungs, and brain are especially sensitive to damage by stress.<em>
|
||||
But all organs are subject to the same kinds of damage.
|
||||
</em></strong>
|
||||
Medical treatments for respiratory distress and macular degeneration in old people are often the same as
|
||||
those used so inappropriately for babies.<strong><em>
|
||||
The good health practices that can prevent the inflammatory and degenerative diseases can often make
|
||||
it possible for damaged tissues to recover, even in old age.</em></strong>
|
||||
</p>
|
||||
|
||||
<p>
|
||||
The pituitary hormones, especially prolactin and TSH, are pro-inflammatory, and darkness increases TSH along
|
||||
with prolactin, so to compensate for a light deficiency, the pituitary should be well-suppressed by adequate
|
||||
thyroid. Armour thyroid or Thyrolar or Cynoplus, Cytomel, would probably be helpful. (Eye-drops containing
|
||||
T3 might be a way to restore metabolic activity more quickly.) Limiting water intake (or using salt
|
||||
generously) helps to inhibit prolactin secretion. The saturated fats protect against the body's stored PUFA,
|
||||
and keeping the blood sugar up keeps the stored fats from being mobilized. Aspirin (or indomethacin) is
|
||||
generally protective to the retina, analogously to its protection against sunburn. Adequate vitamin E is
|
||||
extremely important. There are several prescription drugs that protect against serotonin excess, but thyroid
|
||||
and gelatin (or glycine, as in magnesium glycinate) are protective against the serotonin and melatonin
|
||||
toxicities. Copper and magnesium deficiencies predispose to retinal damage. Red light is protective, blue
|
||||
light (or u.v.) is harmful, so wearing orange lenses would be helpful. Progesterone and pregnenolone, by
|
||||
reducing the stress reactions, should be helpful--in the eye diseases of infancy and old age, as they are in
|
||||
the respiratory distress syndromes.
|
||||
</p>
|
||||
<p><strong><h3>REFERENCES</h3></strong></p>
|
||||
<p>
|
||||
Eksp Klin Farmakol 1999 Mar-Apr; 62(2):58-60.<strong>
|
||||
[Melatonin lowers the threshold of light sensitivity of the human retina]</strong>
|
||||
; Arushanian EB, Ovanesov KB. Department of Pharmacology, Stavropol State Medical Academy, Russia. After
|
||||
chronic use of melatonin (3 mg before night-time for 14 days) campimetry showed a significant decrease of
|
||||
the threshold of brilliance sensitiveness of the retina in the absence of authentic changes of the
|
||||
sensorimotor response latency in individuals of the older age group. A connection between the eye light
|
||||
sensitivity and the direct effect of the hormone on the photoreceptors is suggested.
|
||||
</p>
|
||||
<p>
|
||||
Cochrane Database Syst Rev 2001;4:CD001077. <strong>Restricted versus liberal oxygen exposure for preventing
|
||||
morbidity and mortality in preterm or low birth weight infants</strong> (Cochrane Review). Askie LM,
|
||||
Henderson-Smart DJ.
|
||||
</p>
|
||||
<p>
|
||||
Prog Clin Biol Res 1989;312:95-112. <strong>The metabolism of omega-3 polyunsaturated fatty acids in the
|
||||
eye: the possible role of docosahexaenoic acid and docosanoids in retinal physiology and ocular
|
||||
pathology.</strong> Bazan NG.
|
||||
</p>
|
||||
<p>
|
||||
Biull Eksp Biol Med 1976 Oct;82(10):1181-3. <strong>[Role of the biological activity of serotonin in the
|
||||
production of the "shock lung" syndrome.] ;</strong> Bazarevich GI, Deviataev AM, Likhtenshtein AO,
|
||||
Natsvlishvili BP, Sadeko MK.
|
||||
</p>
|
||||
<p>
|
||||
Invest Ophthalmol Vis Sci 1993 Sep;34(10):2878-80. <strong>
|
||||
An elevated hematogenous photosensitizer in the preterm neonate.</strong> Bynoe LA, Gottsch JD, Sadda
|
||||
SR, Panton RW, Haller EM, Gleason CA.
|
||||
</p>
|
||||
<p>
|
||||
Eur J Endocrinol 1995 Dec;133(6):691-5. <strong>Melatonin enhances cortisol levels in aged but not young
|
||||
women.</strong> Cagnacci A, Soldani R, Yen SS
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Am J Psychiatry 1976 Oct;133(10):1181-6. <strong>Negative effects of melatonin on depression.</strong>
|
||||
Carman JS, Post RM, Buswell R, Goodwin FK. In order to test the efficacy of the pineal neurohumor melatonin
|
||||
on depression, the hormone was administered in varying doses to six moderately to severely depressed
|
||||
patients and two patients with Huntington's chorea in double-blind crossover study. <strong>Melatonin
|
||||
exacerbated symptoms of dysphoria in these patients, as well as causing a loss of sleep and weight and a
|
||||
drop in oral temperature. Melatonin increased cerebrospinal fluid 5-hydroxyindoleacetic acid and
|
||||
calcium</strong> in three of four patients studied. The authors discuss the implications of this
|
||||
finding.
|
||||
</p>
|
||||
<p>
|
||||
Neuroendocrinol Lett 2001 Dec;22(6):432-4. <strong>Melatonin shortens the survival rate of Ehrlich
|
||||
ascites-inoculated mice.</strong> Catrina SB, Curca E, Catrina AI, Radu C, Coculescu M. Dept.
|
||||
Endocrinology II, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania. <a
|
||||
href="mailto:sergiu-bogdan.catrina@molmed.ki.se"
|
||||
target="_blank"
|
||||
>sergiu-bogdan.catrina@molmed.ki.se</a>
|
||||
<hr />
|
||||
</p>
|
||||
<p>
|
||||
J Neurochem 1988 Apr;50(4):1185-93. <strong>Induction of intracellular superoxide radical formation by
|
||||
arachidonic acid and by polyunsaturated fatty acids in primary astrocytic cultures.</strong> Chan PH,
|
||||
Chen SF, Yu AC.
|
||||
</p>
|
||||
<p>
|
||||
Graefes Arch Clin Exp Ophthalmol 1993 Jul;231(7):416-23. <strong>Inhibition of cytochrome oxidase and
|
||||
blue-light damage in rat retina.</strong> Chen E. St. Erik's Eye Hospital, Karolinska Institute,
|
||||
Stockholm, Sweden.<strong>
|
||||
The activity of cytochrome oxidase, outer nuclear layer thickness, and edema were quantitatively
|
||||
evaluated in the blue-light exposed rat retina.</strong>
|
||||
Dark-adapted or cyclic-light reared rats were exposed to blue light with a retinal dose of 380 kJ/m2.
|
||||
Immediately, 1, 2, and 3 day(s) after exposure, the retinas of six rats from each adaptation group were
|
||||
examined. There was no difference between the dark-adapted and cyclic-light reared rats. Immediately after
|
||||
light exposure, cytochrome oxidase activity decreased. The activity in the inner segments remained low at
|
||||
day 1, while severe edema was observed in the inner and outer segments. The outer nuclear layer thickness
|
||||
decreased 1-3 days after exposure. The blue-light exposure inhibited cytochrome oxidase activity and caused
|
||||
retinal injury. Similarity of the injury process in the dark-adapted and cyclic-light reared retinas
|
||||
suggests that rhodopsin was not involved. The inhibition of cytochrome oxidase could be a cause of retinal
|
||||
damage.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Acta Ophthalmol Suppl 1993;(208):1-50. <strong>Inhibition of enzymes by short-wave optical radiation and its
|
||||
effect on the retina.</strong> Chen E. Eye Laboratory, St. Erik's Eye Hospital, Stockholm, Sweden.
|
||||
"Exposure to short-wave optical radiation is a potential hazard for vision. In the present study, blue-light
|
||||
damage is studied in rat retina." <strong>"Blue light inhibited cytochrome
|
||||
</strong>
|
||||
<strong>oxidase</strong>
|
||||
at a retinal dose of about 110 kJ/m2. This inhibition was reversible, and is probably related to the light
|
||||
regulation of retinal metabolism. At a retinal dose of about 380 kJ/m2, the inhibition of cytochrome oxidase
|
||||
was followed consecutively by a probable redistribution of chlorine and potassium in the inner and outer
|
||||
segments, damage to the mitochondria in the inner segments, edema in the inner and outer segments, and
|
||||
progressive degeneration of photoreceptor cells. Dark adaptation did not increase the blue-light retinal
|
||||
injury. <strong>These findings support the hypothesis that inhibition of cytochrome oxidase is one of the
|
||||
causes of blue-light retinal damage.</strong>"
|
||||
</p>
|
||||
<p>
|
||||
Aust N Z J Ophthalmol 1997 May;25 Suppl 1:S73-5. <strong>Retinal control of scleral precursor
|
||||
synthesis.</strong> Devadas M, Morgan
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Eur J Pharmacol 1990 Jul 3;182(2):313-25. <strong>Antidepressant-like activity of the melatonin receptor
|
||||
antagonist, luzindole (N-0774), in the mouse behavioral despair test.</strong> Dubocovich ML, Mogilnicka
|
||||
E, Areso PM.
|
||||
</p>
|
||||
<p>
|
||||
J Pharmacol Exp Ther 1988 Sep;246(3):902-10. <strong>Luzindole (N-0774): a novel melatonin</strong>
|
||||
<strong>
|
||||
receptor antagonist.</strong> Dubocovich ML.
|
||||
</p>
|
||||
<p>
|
||||
Exp Eye Res 1985 Oct;41(4):497-507. <strong>The diurnal susceptibility of rat retinal photoreceptors to
|
||||
light-induced damage.</strong> Duncan TE, O'Steen WK. Exposure of albino rats to high intensity light
|
||||
results in rapid, graded loss of photoreceptors. The hormonal status and age of an animal at the time of
|
||||
exposure affect the severity of light-induced retinal damage. The adrenal axis and pituitary hormones
|
||||
(prolactin) have been demonstrated previously to affect the degree of cell death in the retina. Because
|
||||
circadian rhythms for adrenal and pituitary secretion have been demonstrated in the rat, a series of
|
||||
experiments was undertaken to determine if a diurnal pattern of retinal susceptibility to light damage
|
||||
exists which might be related to endogenous endocrine rhythms. Male Sprague-Dawley rats were exposed to 4 hr
|
||||
of high intensity fluorescent light for 8 consecutive days during different phases of the 14:10 hr light:
|
||||
dark animal room light cycle. Morphometric analysis performed at the light microscopic level 2 weeks after
|
||||
exposure demonstrated a differential susceptibility to light-induced cell death depending upon the period
|
||||
during the light-dark cycle when animals received their daily light exposure. Neuronal cell death was
|
||||
confined to the outer nuclear layer as previously described. <strong>The retinas of animals exposed during
|
||||
the middle of the dark period or during the first 5 hr of the light period were significantly more
|
||||
damaged than the retinas of animals exposed during the last 9 hr of the light period.</strong> Control
|
||||
groups for the relative amounts of dark-adaptation between groups suggested that the diurnal susceptibility
|
||||
to light damage was not solely dependent upon the degree of dark adaptation. These results demonstrate a
|
||||
diurnal susceptibility of photoreceptors to light-induced cell death.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Nature 1983 Dec 22-1984 Jan 4;306(5945):782-4. <strong>Melatonin is a potent modulator of dopamine release
|
||||
in the retina.</strong> Dubocovich ML.
|
||||
</p>
|
||||
<p>
|
||||
Semin Perinatol 2000 Aug;24(4):291-8. <strong>Environmental light and the preterm infant.
|
||||
</strong>Fielder AR, Moseley MJ. The lighting environment of the preterm baby is quite unlike that
|
||||
experienced at any other time of life. Physical and physiological factors control how much light reaches the
|
||||
retina of the preterm baby. With respect to the former, although many neonatal intensive care units are
|
||||
brightly and continuously lit, there is a trend to employ lower levels of illumination and to introduce
|
||||
cycling regimens. Physiological determinants of the retinal light dose include: eyelid opening and
|
||||
transmission, pupil diameter and the transmission characteristics of the ocular media. Early exposure to
|
||||
light does not significantly hasten or retard normal visual development, and it is not a factor in the
|
||||
development of retinopathy of prematurity. However, ambient neonatal intensive care unit illumination may be
|
||||
implicated in some of the more subtle visual pathway sequelae that cannot be attributed to other major
|
||||
complications of preterm birth including altered visual functions and arrested eye growth.
|
||||
</p>
|
||||
<p>
|
||||
Pediatrics 1992 Apr;89(4 Pt 1):648-53. <strong>
|
||||
Light and retinopathy of prematurity: does retinal location offer a clue?</strong> Fielder AR, Robinson
|
||||
J, Shaw DE, Ng YK, Moseley MJ. Nursery illumination has been implicated in the pathogenesis of retinopathy
|
||||
of prematurity (ROP), although the results of recent studies are conflicting. The data base for this article
|
||||
is a prospective ROP study on 607 infants of birth weight less than or equal to 1700 g including 35 larger
|
||||
siblings from multiple births when 1 infant fulfilled the birth weight criteria. Retinopathy commences
|
||||
preferentially in the nasal retina of the most immature neonate and is less likely to develop, or its onset
|
||||
is delayed, in the superior and inferior<strong>
|
||||
regions. These findings cannot be fully accounted for by regional vascular and neuroanatomical
|
||||
variations. Radiometric and physiological evidence suggests that the very immature neonate, most at risk
|
||||
of developing severe ROP, receives the greatest retinal irradiance. Furthermore, ROP commences in the
|
||||
areas of the retina receiving the highest light dose, and its onset is either retarded or inhibited in
|
||||
the darker retinal regions. Further studies are required to</strong> determine whether early exposure to
|
||||
light is a factor in the development of ROP. If a causal relationship is proven, here at least is one
|
||||
modality that can easily and immediately be controlled.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
N Engl J Med 1985 Aug 15;313(7):401-4. <strong>Effect of bright light in the hospital nursery on the
|
||||
incidence of retinopathy of prematurity.</strong> Glass P, Avery GB, Subramanian KN, Keys MP, Sostek AM,
|
||||
Friendly DS. The preterm infant is subjected to prolonged exposure to ambient nursery illumination at levels
|
||||
that have been found to produce retinal damage in animals. We prospectively investigated the effect of
|
||||
exposure to light in two intensive care nurseries by comparing the incidence of retinopathy of prematurity
|
||||
among 74 infants from the standard bright nursery environment (median light level, 60 foot-candles [ftc])
|
||||
with the incidence among 154 infants of similar birth weight for whom the light levels were reduced (median,
|
||||
25 ftc). <strong>There was a higher incidence of retinopathy of prematurity in the group of infants who had
|
||||
been exposed to the brighter nursery lights,</strong> particularly in those with birth weights below
|
||||
1000 g (86 percent vs. 54 per cent, P less than 0.01 by chi-square test). We conclude that the high level of
|
||||
ambient illumination commonly found in the hospital nursery may be one factor contributing to retinopathy of
|
||||
prematurity and that safety standards with regard to current lighting practices should be reassessed.
|
||||
</p>
|
||||
<p>
|
||||
Doc Ophthalmol 1990 Mar;74(3):195-203. <strong>Light and the developing retina.
|
||||
</strong>Glass P. George Washington University School of Medicine & Health Sciences, Washington, DC.
|
||||
<strong>"Retinopathy of prematurity (ROP) has increased in the United States in the past decade.</strong>"
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Pediatr Res 1987 Oct;22(4):414-6. Calcemic responses to photic and pharmacologic manipulation of serum
|
||||
melatonin. Hakanson DO, Penny R, Bergstrom WH.
|
||||
</p>
|
||||
<p>
|
||||
Pediatr Res 1990 Jun;27(6):571-3. <strong>Pineal and adrenal effects on calcium homeostasis in the
|
||||
rat.</strong> Hakanson DO, Bergstrom WH.
|
||||
</p>
|
||||
<p>
|
||||
Science 1981 Nov 13;214(4522):807-9. <strong>Phototherapy-induced hypocalcemia in newborn rats: prevention
|
||||
by melatonin.</strong> Hakanson DO, Bergstrom WH.
|
||||
</p>
|
||||
<p>
|
||||
Doc Ophthalmol 1992;79(2):141-50. <strong>Diurnal variations in the electroretinographic c-wave and retinal
|
||||
melatonin content in rats with inherited retinal dystrophy.</strong> Hawlina M, Jenkins HG, Ikeda H.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
<strong>J.A.M.A. 90:353 (Feb. 25) 1928. The Prevention and Treatment of Asphyxia in the New-Born, Henderson,
|
||||
Yandell.</strong>
|
||||
</p>
|
||||
<p>
|
||||
Neuroendocrinology 2001 Feb;73(2):111-22. <strong>Estrogen modulates alpha(1)/beta-adrenoceptor- induced
|
||||
signaling and melatonin production in female rat pinealocytes.</strong> Hernandez-Diaz FJ, Sanchez JJ,
|
||||
Abreu P, Lopez-Coviella I, Tabares L, Prieto L, Alonso R.
|
||||
</p>
|
||||
<p>
|
||||
J Neurosci Res 1989 Oct;24(2):247-50. <strong>Brain mitochondrial swelling induced by arachidonic acid and
|
||||
other long chain free fatty acids.</strong> Hillered L, Chan PH.
|
||||
</p>
|
||||
<p>
|
||||
J Neurosci Res 1988;19(1):94-100. <strong>Effects of arachidonic acid on respiratory activities in isolated
|
||||
brain mitochondria.</strong>
|
||||
|
||||
Hillered L, Chan PH.
|
||||
</p>
|
||||
<p>
|
||||
J Neurosci Res 1988 Aug;20(4):451-6. <strong>Role of arachidonic acid and other free fatty acids in
|
||||
mitochondrial dysfunction in brain ischemia.</strong> Hillered L, Chan PH.
|
||||
</p>
|
||||
<p>
|
||||
J Neurosci Res 1989 Oct;24(2):247-50. <strong>
|
||||
Brain mitochondrial swelling induced by arachidonic acid and other long chain free fatty acids.</strong>
|
||||
Hillered L, Chan PH.
|
||||
</p>
|
||||
<p>
|
||||
J Clin Epidemiol 1992 Nov;45(11):1265-87. <strong>Oxygen as a cause of blindness in premature infants:
|
||||
"autopsy" of a decade of errors in clinical epidemiologic research.</strong> Jacobson RM, Feinstein AR.
|
||||
Clinical Epidemiology Unit, Yale University School of Medicine, New Haven, CT 06510. "Several intellectual
|
||||
"autopsies" have recently reviewed errors in clinical epidemiologic studies of causation, such as the
|
||||
original claim that amyl nitrite "poppers" caused AIDS. The current autopsy was done to determine why it
|
||||
took<strong>
|
||||
more than a decade--1942 to 1954--to end an iatrogenic epidemic in which high-dose oxygen therapy led to
|
||||
retrolental fibroplasia (RLF) in premature infants, blinding about 10,000 of them.
|
||||
</strong>The autopsy revealed a museum of diverse intellectual pathology."
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Curr Eye Res 2001 Jul;23(1):11-9. <strong>Rod outer segments mediate mitochondrial DNA damage and apoptosis
|
||||
in human retinal pigment epithelium.
|
||||
</strong>
|
||||
Jin GF, Hurst JS, Godley BF.
|
||||
</p>
|
||||
<p>
|
||||
Endocrinol Exp 1976 Jun;10(2):131-7. <strong>Diurnal variation in the effect of melatonin on plasma and
|
||||
muscle free fatty acid levels in the pigeon.</strong>
|
||||
John TM, George JC. Pigeons maintained on standard diet and held under 12 h daily photo-period in a
|
||||
controlled environmental room, were given intravenous injections of melatonin. A low dose (1.25 mg/kg body
|
||||
weight) of melatonin when given in the middle of the<strong>
|
||||
scotophase, produced a significant increase in plasma FFA when estimated at 20 min and 90 min
|
||||
post-injection, whereas no significant change was seen with injections given in the middle of the
|
||||
photophase. No significant change in muscle FFA level was obtained either during the photophase or the
|
||||
scotophase</strong> when estimated at 90 min postinjection. With a higher dose (5 mg/kg body weight) of
|
||||
melatonin given in the scotophase, on the other hand, a significant increase<strong>
|
||||
in both plasma as well as muscle FFA levels was obtained at 90 min</strong> post-injection but there was
|
||||
no effect on plasma FFA at 20 min or 90 min post-injection in the photophase and at 20 min in the
|
||||
scotophase. It is concluded that melatonin has a lipid mobilizing action in the pigeon when administered
|
||||
during the scotophase.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Arch Int Physiol Biochim 1983 Jul;91(2):115-20. <strong>Diurnal impact of locomotory activity and melatonin
|
||||
and N-acetylserotonin treatment on blood metabolite levels in the rainbow trout.</strong> John TM,
|
||||
Beamish FW, George JC. In rainbow trout forced to swim continuously at sustained speeds for six weeks,
|
||||
selected doses of melatonin or N-acetylserotonin (1.25 and 5.0 mg/kg body weight) injections caused no
|
||||
change in haematocrit. Melatonin did not produce any significant change in plasma glucose level either in
|
||||
the photophase or in the scotophase. However, diurnal variations were observed in the effect of melatonin on
|
||||
plasma free fatty acids (FFA). Melatonin was ineffective in causing<strong>
|
||||
any change in plasma FFA level during photophase but during scotophase, the higher dose (5.0 mg/kg)
|
||||
produced an increase in FFA while the lower dose (1.25 mg/kg) had no effect, N-acetylserotonin
|
||||
administration produced diurnal</strong> variation in its effect on both plasma glucose and FFA. The
|
||||
higher dose of N-acetylserotonin brought about a drop in plasma glucose level during photophase, but both
|
||||
doses were ineffective during scotophase. N-acetylserotonin produced no change in FFA during photophase, but
|
||||
during scotophase tended to lower FFA level. It is suggested that exercise shortens the time required to
|
||||
cause a hypoglycemic effect of N-acetylserotonin during photophase, blocks FFA release-inhibiting action of
|
||||
melatonin observed in photophase, and minimizes the time required for the FFA mobilizing action of melatonin
|
||||
in scotophase.
|
||||
</p>
|
||||
<p>
|
||||
J Neural Transm 1977;40(2):87-97. <strong>The adrenal medulla may mediate the increase in pineal melatonin
|
||||
synthesis induced by stress, but not that caused by exposure to darkness.</strong> Lynch HJ, Ho M,
|
||||
Wurtman RJ.
|
||||
</p>
|
||||
<p>
|
||||
Bull Acad Natl Med 2000;184(2):415-28; discussion 428-30. <strong>[Pulmonary toxicity of oxygen]</strong>
|
||||
[Article in French] Mantz JM, Stoeckel ME.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Br J Pharmacol 1977 Dec;61(4):607-14. <strong>The action of melatonin on single amphibian pigment cells in
|
||||
tissue culture.</strong> Messenger EA, Warner AE.
|
||||
</p>
|
||||
<p>
|
||||
Oftalmol Zh 1989;(8):469-73. <strong>[The early diagnosis, evaluation of treatment results and modelling of
|
||||
certain aspects of the pathogenesis of retinal dystrophy]</strong>
|
||||
; Mironova EM, Pavlova ON, Ronkina TI. The paper analyses results after a study of the functional state of
|
||||
pigmented epithelium and the retina in patients with a dry form of senile macular dystrophy as well as of
|
||||
experimental simulation of retinal dystrophy with the help of melatonin and its treatment by taurine.
|
||||
<strong>Melatonin in 10(-3) M concentration leads to development of dystrophic changes</strong> in pigmented
|
||||
epithelium and interacting with it structures, this being testified by remarkable lowering of EOG parameters
|
||||
and electron microscopic findings. Taurine in 10(-3) <strong>M concentration blocks the action of exogenic
|
||||
melatonin as well as has a pronounced positive action on metabolism of dystrophic changes in the
|
||||
pigmented epithelium and photoreceptors. Examination of patients with different stages of a dry form of
|
||||
senile</strong>
|
||||
macular dystrophy revealed statistically significant reduction of KA cEOG at the initial stage of the
|
||||
disease in the presence of normal ERG parameters. In 18% of patients, supernormal values of KA were
|
||||
recorded, that are likely to reflect the presence of "predystrophic hyperactivity" of the pigmented
|
||||
epithelium cells. In progression of the process, the further reduction of electrophysiologic values was
|
||||
recorded. The data obtained speaks about the important role of pigmented epithelium pathology in the
|
||||
pathogenesis of senile macular dystrophy and about high information value of the cEOG method for detection
|
||||
of early stages of the disease. It is believed that disturbances in melatonin metabolism can be one of
|
||||
causes leading to development of retinal dystrophy.
|
||||
</p>
|
||||
<p>
|
||||
J Clin Endocrinol Metab 1977 Oct;45(4):768-74. <strong>The effects of oral melatonin on skin color and on
|
||||
the release of pituitary hormones.</strong>
|
||||
Nordlund JJ, Lerner AB. "We studied the effects of prolonged ingestion of melatonin, 1 g per day, on skin
|
||||
color and the serum levels of pituitary hormones in 5 human subjects with hyperpigmented skin. Melatonin
|
||||
lightened hyperpigmented skin of one patient with untreated adrenogenital syndrome, but had no effect on
|
||||
three patients' skin with idiopathic hyperpigmentation and one patient with treated Addison's disease."
|
||||
</p>
|
||||
<p>
|
||||
Invest Ophthalmol 1976 Oct;15(10):869-72. <strong>Hormonal influences on photoreceptor damage: the pituitary
|
||||
gland and ovaries.</strong> Olafson RP, O'Steen WK. To determine whether the absence of pituitary or
|
||||
ovarian hormones would influence retinal degeneration, female albino rats were either hypophysectomized
|
||||
(HYPEX) or ovariectomized (OVEX) before pubery. Later, they were exposed to continuous light for periods up
|
||||
to 45 days. Retinas evaluated by light microscopic measurements showed damage to the outer nuclear layer
|
||||
(ONL) and photoreceptor layer in both the operated and intact, control rats. However, the degree of damage
|
||||
observed in retinas of HYPEX and OVEX rats was significantly less than that observed in retinas of intact
|
||||
rats exposed to the same lighting conditions. Therefore, hypophysectomy and ovariectomy, which influence the
|
||||
normal development of sexual maturation when performed on immature rats, significantly reduce photoreceptor
|
||||
damage in adult rats exposed to continuous light.
|
||||
</p>
|
||||
<p>
|
||||
Invest Ophthalmol Vis Sci 1996 Oct;37(11):2243-57. <strong>Retinal light damage in rats with altered levels
|
||||
of rod outer segment docosahexaenoate. Organisciak DT, Darrow RM, Jiang YL, Blanks JC.</strong>
|
||||
|
||||
PURPOSE: To compare retinal light damage in rats with either normal or reduced levels of rod outer segment
|
||||
(ROS) docosahexaenoic acid. METHODS: Weanling male albino rats were maintained in a weak cyclic light
|
||||
environment and fed either a nonpurified control diet or a purified diet deficient in the linolenic acid
|
||||
precursor of docosahexaenoic acid (DHA). Half the rats on the deficient diet were given linseed oil,
|
||||
containing more than 50 mol% linolenic acid, once a week to maintain ROS DHA at near normal levels. Diets
|
||||
and linseed oil supplementation were continued for 7 to 12 weeks. To replenish DHA in their ROS, some
|
||||
10-week-old rats on the deficient diet were given linseed oil three times a week for up to 3 additional
|
||||
weeks. Groups of animals were killed at various times for ROS fatty acid determinations or were exposed to
|
||||
intense green light using intermittent or hyperthermic light treatments. The extent of retinal light damage
|
||||
was determined biochemically by rhodopsin or photoreceptor cell DNA measurements 2 weeks after exposure and
|
||||
morphologically by light and electron microscopy at various times after light treatment. RESULTS: <strong
|
||||
>Rats maintained for 7 to 12 weeks on the linolenic acid-deficient diet had significantly lower levels of
|
||||
DHA</strong> and significantly higher levels of n-6 docosapentaenoic acid (22:5n-6) in their ROS than
|
||||
deficient-diet animals supplemented once a week with linseed oil or those fed the nonpurified control diet.
|
||||
As determined by rhodopsin levels and photoreceptor cell DNA measurements, deficient diet rats<strong>
|
||||
exhibited protection against retinal damage from either intermittent or hyperthermic light exposure.
|
||||
However, the unsaturated fatty acid content of ROS</strong> from all three dietary groups was the same
|
||||
and greater than 60 mol%. In 10 week-old deficient-diet rats given linseed oil three times a week, ROS DHA
|
||||
was unchanged for the first 10 days, whereas 22:5n-6 levels declined by 50%. After 3 weeks of treatment with
|
||||
linseed oil, ROS DHA and 22:5n-6 were nearly the same as in rats supplemented with linseed oil from weaning.
|
||||
The time course of susceptibility to retinal light damage, however, was different. Hyperthermic light damage
|
||||
in rats given linseed oil for only 2 days was the same as for rats always fed the deficient diet. Six days
|
||||
after the start of linseed oil treatment, retinal light damage was the same as in rats given the linseed oil
|
||||
supplement from weaning. Morphologic alterations in ROS of linseed oil-supplemented rats immediately after
|
||||
intermittent light exposure were more extensive than in either the deficient-diet animals or those fed the
|
||||
control diet. The deficient-diet rats also exhibited better preservation of photoreceptor cell nuclei and
|
||||
structure 2 weeks after exposure. CONCLUSIONS: Rats fed a diet deficient in the linolenic acid precursor of
|
||||
DHA are protected against experimental retinal light damage. The relationship between retinal light damage
|
||||
and ROS lipids does not depend on the total unsaturated fatty acid content of ROS; the damage appears to be
|
||||
related to the relative levels of DHA and 22:5n-6.
|
||||
</p>
|
||||
<p>
|
||||
Exp Neurol 1970 May;27(2):194-205.<strong>
|
||||
Retinal and optic nerve serotonin and retinal degeneration as influenced by photoperiod.</strong>
|
||||
O'Steen WK.
|
||||
</p>
|
||||
<p>
|
||||
Invest Ophthalmol Vis Sci 1982 Jan;22(1):1-7. <strong>Antagonistic effects of adrenalectomy and
|
||||
ether/surgical stress on light-induced photoreceptor damage.</strong> O'Steen WK, Donnelly JE.
|
||||
Light-induced damage to retinal photoreceptors in influenced by the endocrine status of the animal during
|
||||
the period of exposure. Experimental manipulation of the pituitary gland and of prolactin levels has been
|
||||
shown to affect retinal damage in rats exposed to visible light. When rats are experimentally stressed,
|
||||
prolactin secretion from the pituitary gland occurs as does secretion of adrenocorticotropic hormone (ACTH),
|
||||
which stimulates the release of adrenal cortical hormones. Since prolactin appears to influence retinal
|
||||
damage and since stressed animals have increased serum levels of prolactin, a comparison of photoreceptor
|
||||
damage in animals in which the adrenal glands were removed or which had been experimentally stressed was
|
||||
undertaken in this study. Adrenalectomized rats had thicker outer nuclear layer (ONL) measurements than
|
||||
those found in sham-operated animals. Stressed rats had severely damaged retinas with cystic degeneration
|
||||
and significantly reduced ONL thickness measurements as compared to retinas of unstressed and
|
||||
adrenalectomized rats. <strong>Therefore hormones of the pituitary-adrenal system appear to be involved in
|
||||
the damage to the retina by light, and this response may be related to an interaction or synergism
|
||||
between the adrenal gland, stress, and prolactin secretion.</strong>
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Brain Res 1990 Nov 26;534(1-2):99-105. <strong>Water deprivation protects photoreceptors against light
|
||||
damage.</strong> O'Steen WK, Bare DJ, Tytell M, Morris M, Gower DJ. "Photoreceptor cell death after
|
||||
light-damage and during aging in rats is associated with the hormonal status of the animal, as well as other
|
||||
environmental and intrinsic factors. Restricted caloric intake extends the life of rodents and is usually
|
||||
accompanied by a reduction in water consumption. In this study, male and female rats were placed on
|
||||
restricted water intake for either 3 or 7 days to induce dehydration." "Photoreceptor cells of 7-day,
|
||||
dehydrated male and female rats survived light-damage significantly better than those allowed water ad
|
||||
libitum; however, after 3 days of water restriction, only the male rats demonstrated protection from
|
||||
photodamage." "AVP increased by 350% during the 7-day period of dehydration. Protection of photoreceptors
|
||||
from light-damage in this study may be correlated with osmotically stimulated changes in the retinas of
|
||||
dehydrated animals."
|
||||
</p>
|
||||
<p>
|
||||
Brain Res 1985 Oct 7;344(2):231-9. <strong>Neuronal damage in the rat retina after chronic stress.</strong>
|
||||
O'Steen WK, Brodish A. Long-term exposure to escapable foot shock has been used to determine if chronic
|
||||
stress influences neuronal cell death in the retina of albino and pigmented rats. Histopathologic and
|
||||
morphometric approaches analyzed changes in photoreceptors and neurons of the bipolar and ganglion cell
|
||||
layers of the retina. Albino Fischer rats when exposed to chronic stress for 4-8 h daily for 1 week to 6
|
||||
months, developed severe retinal damage, as compared to unstressed control retinas, with reduction in
|
||||
photoreceptor and bipolar neurons, particularly in the superior central retina. The damage was observed in
|
||||
male and female rats, but males appeared to be more susceptible to the influence of stress than female
|
||||
animals. Ganglion cells were unaffected. Photoreceptor destruction did not occur in Long-Evans pigmented
|
||||
rats under identical experimental conditions. The results suggest that: <strong>input of the sensory
|
||||
stimulus, light, to the retina of stressed rats augmented neuronal damage and might be required for its
|
||||
initiation;</strong> and hormones and/or neurotransmitters associated with long-term chronic stress
|
||||
might be related to increased neuronal cell death in the mammalian retina.
|
||||
</p>
|
||||
<p>
|
||||
Invest Ophthalmol Vis Sci 1977 Oct;16(10):940-6. <strong>Effects of hypophysectomy, pituitary gland
|
||||
homogenates and transplants, and prolactin on photoreceptor destruction.</strong> O'Steen WK, Kraeer SL.
|
||||
"Prepubertal removal of the pituitary gland, which in young animals influences sexual maturation, reduces
|
||||
significantly the amount of retinal photoreceptor destruction when the rats are exposed to continuous
|
||||
illumination in adulthood. When crude pituitary gland homogenate is administered to adult rats
|
||||
hypophysectomized prior to puberty, photoreceptor destruction is more severe. Transplantation of whole
|
||||
pituitary glands to the kidney capsule of hypophysectomized rats also reduces the effect of pituitary gland
|
||||
removal and results in more extensive damage to receptor cells than found in hypophysectomized, adult
|
||||
animals. <strong>Hypophysectomized rats treated with prolactin had more severe retinal damage than
|
||||
untreated, hypophysectomized rats."</strong> "Results of these studies indicate the hormones of the
|
||||
pituitary gland have a regulatory influence on the severity of light-induced, retinal photoreceptor damage
|
||||
in the rat."
|
||||
</p>
|
||||
<p>
|
||||
Life Sci 1985 Nov 4;37(18):1743-6. <strong>Stress-induced synthesis of melatonin: possible involvement of
|
||||
the endogenous monoamine oxidase inhibitor (tribulin).</strong> Oxenkrug GF, McIntyre IM.
|
||||
</p>
|
||||
<p>
|
||||
Mech Ageing Dev 2000 Jan 10;112(3):169-83. <strong>Double bond content of phospholipids and lipid
|
||||
peroxidation negatively correlate with maximum longevity in the heart of mammals.</strong> Pamplona R,
|
||||
Portero-Otin M, Ruiz C, Gredilla R, Herrero A, Barja G.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Prostaglandins Leukot Essent Fatty Acids 2001 Feb;64(2):75-80. <strong>Comparative studies on lipid
|
||||
peroxidation of microsomes and mitochondria obtained from different rat tissues: effect of retinyl
|
||||
palmitate.</strong> Piergiacomi VA, Palacios A, Catala A.
|
||||
</p>
|
||||
<p>
|
||||
Curr Eye Res 1992 Oct;11(10):939-53. <strong>Oxygen-induced retinopathy in the rat: hemorrhages and
|
||||
dysplasias may lead to retinal detachment.</strong> Penn JS, Tolman BL, Lowery LA, Koutz CA.
|
||||
</p>
|
||||
<p>
|
||||
Vision Res 1995 May;35(9):1247-64. <strong>Studies on the role of the retinal dopamine/melatonin system in
|
||||
experimental refractive errors in chickens.</strong>
|
||||
|
||||
Schaeffel F, Bartmann M, Hagel G, Zrenner E.
|
||||
</p>
|
||||
<p>
|
||||
Exp Clin Endocrinol Diabetes 1997;105(2): 109-12. <strong>Melatonin</strong>
|
||||
<strong>
|
||||
and serotonin regulate the release of insulin-like growth factor-I, oxytocin and progesterone by
|
||||
cultured human granulosa cells.</strong> Schaeffer HJ, Sirotkin AV.
|
||||
</p>
|
||||
<p>
|
||||
Zh Evol Biokhim Fiziol 1989 Jan-Feb;25(1):52-9. <strong>[Seasonal characteristics of the functioning of the
|
||||
hypophysis-gonad system in the suslik</strong> Citellus parryi] Shvareva NV, Nevretdinova ZG. "In
|
||||
females, FSH was found in the blood in October, being absent from November to<strong>
|
||||
January; beginning from February, it may be found both in sleeping and active</strong> animals." <strong
|
||||
>"Estradiol secretion was noted in hibernating females, whereas progesterone was found in the blood only in
|
||||
May."</strong>
|
||||
</p>
|
||||
|
||||
<p>
|
||||
J Pineal Res 1985;2(1):39-49. <strong>Melatonin and N-acetylserotonin stress responses: effects of type of
|
||||
stimulation and housing conditions.</strong> Seggie J, Campbell L, Brown GM, Grota LJ.
|
||||
</p>
|
||||
<p>
|
||||
Acta Ophthalmol Scand 2001 Aug;79(4):428-30. <strong>Presumed sertraline maculopathy.</strong> Sener EC,
|
||||
Kiratli H.
|
||||
</p>
|
||||
<p>
|
||||
Paediatr Perinat Epidemiol 1999 Apr;13(2):128-30. <strong>Effects of premature exposure to light: a
|
||||
credibility struggle.</strong> Silverman WA.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
J Pineal Res 1994 Oct;17(3):112-7. <strong>Direct influence of melatonin on steroid, nonapeptide hormones,
|
||||
and cyclic nucleotide secretion by granulosa cells isolated from porcine ovaries.</strong> Sirotkin AV.
|
||||
<strong>
|
||||
"It was found that melatonin is able to inhibit progesterone and stimulate estradiol secretion."</strong
|
||||
> "The present observations suggest a direct effect of melatonin on the steroid, nonapeptide hormone, and
|
||||
cyclic nucleotide release from porcine ovarian cells."
|
||||
</p>
|
||||
<p>
|
||||
J Pineal Res 1994 Oct;17(3):112-7. <strong>Direct influence of melatonin on steroid, nonapeptide hormones,
|
||||
and cyclic nucleotide secretion by granulosa cells isolated from porcine ovaries.</strong> Sirotkin AV.
|
||||
</p>
|
||||
<p>
|
||||
Prog Clin Biol Res 1989;312:229-49. <strong>Inhibitors of the arachidonic acid cascade in the management of
|
||||
ocular inflammation.</strong>
|
||||
|
||||
Srinivasan BD, Kulkarni PS.
|
||||
</p>
|
||||
<p>
|
||||
J Nutr 2000 Dec;130(12):3028-33. <strong>Polyunsaturated (n-3) fatty acids susceptible to peroxidation are
|
||||
increased in plasma and tissue lipids of rats fed docosahexaenoic acid-containing oils.</strong> Song
|
||||
JH, Fujimoto K, Miyazawa T.<strong>
|
||||
"Thus, high incorporation of (n-3) fatty acids (mainly DHA) into plasma and tissue lipids due to
|
||||
DHA-containing oil ingestion may undesirably affect tissues by enhancing</strong>
|
||||
susceptibility of membranes to lipid peroxidation and by disrupting the antioxidant system."
|
||||
</p>
|
||||
<p>
|
||||
Acta Ophthalmol (Copenh) 1992 Feb;70(1):115-22. <strong>Effects of steady electric fields on human retinal
|
||||
pigment epithelial cell orientation and migration in culture.</strong> Sulik GL, Soong HK, Chang PC,
|
||||
Parkinson WC, Elner SG, Elner VM
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Ned Tijdschr Geneeskd 2001 Dec 29;145(52):2521-5. <strong>[Administration of glucocorticosteroids to
|
||||
premature infants: increasing evidence of adverse effects]</strong> [Article in Dutch] van Bel F.
|
||||
<strong>"Neonatal glucocorticosteroid therapy is increasingly being used for the prevention of chronic lung
|
||||
disease in very premature infants. In the short term this therapy is usually successful. There is,
|
||||
however, increasing evidence for long-term adverse effects. In particular there seems to be an increased
|
||||
chance of abnormal brain development, which later results in locomotory dysfunction, developmental delay
|
||||
and cerebral palsy.</strong>"
|
||||
</p>
|
||||
<p>
|
||||
Brain Res 1984 Feb 27;294(1):166-8. <strong>Pineal methoxyindoles depress calcium uptake by rat brain
|
||||
synaptosomes.</strong> Vacas MI, Keller Sarmiento MI, Cardinali DP.
|
||||
</p>
|
||||
<p>
|
||||
Ann N Y Acad Sci 1994 Nov 17;738:408-18. <strong>Serotonin binding proteins: an in vitro model system for
|
||||
monoamine-related neurotoxicity.</strong> Vauquelin G, Del Rio MJ, Pardo CV.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
J Hypertens Suppl 1985 Dec;3 Suppl 3:S107-9. <strong>Seasonal variation in the development of stress-induced
|
||||
systolic hypertension in the rat.</strong>
|
||||
Weinstock M, Blotnick S, Segal M. "Seasonal variation in blood pressure in human hypertensives prompted us
|
||||
to investigate whether such a phenomenon also occurs in rats made hypertensive by environmental stress."
|
||||
<strong>
|
||||
"Systolic pressure increased by 14-25 mmHg after 6-8 weeks of stress from October to January. Artificial
|
||||
environmental light for 15 h prevented development of hypertension by stress,
|
||||
</strong>
|
||||
which could also be reversed by acute administration of propranolol." "Hypertensive rats had significantly
|
||||
greater relative heart and adrenal weights. This phenomenon can be explained by amplification of<strong>
|
||||
sympathetic pressor activity by stress hormones, adrenaline, corticosterone and prolactin, under the
|
||||
influence of melatonin."</strong>
|
||||
</p>
|
||||
<p>
|
||||
Invest Ophthalmol Vis Sci 1992 May;33(6):1894-902. <strong>Melatonin increases photoreceptor susceptibility
|
||||
to light-induced damage.</strong> Wiechmann AF, O'Steen WK. <strong>"Pinealectomy has been shown to
|
||||
protect photoreceptors from light-induced damage, and melatonin treatment has been reported to increase
|
||||
the degree of photoreceptor damage in albino rats.</strong>" "The animals that received daily melatonin
|
||||
injections (100 micrograms) in the late afternoon (3 hr before lights off) for 1-3 days before photodamage
|
||||
showed an approximate 30% greater reduction compared with sham control animals in ONL thickness in the
|
||||
superior quadrant, the area most susceptible to light damage. Melatonin injections given after the
|
||||
photodamage did not affect ONL thickness. Although retinal susceptibility to light damage varied with time
|
||||
of day, the degree to which melatonin increased the degree of damage appeared unaffected by the time of day.
|
||||
These results suggest that melatonin may be involved in some aspects of photoreceptor sensitivity to light
|
||||
damage."
|
||||
</p>
|
||||
|
||||
<p>
|
||||
J Neurochem 1986 Oct;47(4):1181-9. <strong>Effects of arachidonic acid on glutamate and gamma-aminobutyric
|
||||
acid uptake in primary cultures of rat cerebral cortical astrocytes and neurons.</strong> Yu AC, Chan
|
||||
PH, Fishman RA.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
© Ray Peat 2006. All Rights Reserved. www.RayPeat.com
|
||||
</p>
|
||||
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|
||||
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|
||||
Reference in New Issue
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