beta-carotene and Blindness

Vitamin A and its derivatives (retinoids) are essential components in vision; they contribute to pattern formation during development and exert multiple effects on cell differentiation. It has been known for 70 y that the key step in vitamin A biosynthesis is the oxidative cleavage of a carotenoid with provitamin A activity. While a detailed biochemical characterization of the respective enzymes could be achieved in cell-free homogenates, their molecular nature has remained elusive for a long time. Recent research led to the identification of genes encoding two different types of carotene oxygenases from animal species. The molecular cloning of these different types of animal carotene oxygenases establishes the existence of a family of carotenoid metabolizing enzymes in animals heretofore described in plants. With these tools in hands, old questions in vitamin A research can be definitively addressed on the molecular levels contributing to a mechanistic understanding of the regulation of vitamin A homeostasis or tissue specificity of vitamin A formation, with impact on animal physiology and human health.

Topics: Animals; beta Carotene; beta-Carotene 15,15'-Monooxygenase; Blindness; Carotenoids; Drosophila melanogaster; Drosophila Proteins; Growth; Humans; Mutation; Organ Specificity; Oxygenases; Phylogeny; Vitamin A

The carotenoid pigment astaxanthin has important applications in the nutraceutical, cosmetics, food and feed industries. Haematococcus pluvialis is the richest source of natural astaxanthin and is now cultivated at industrial scale. Astaxanthin is a strong coloring agent and a potent antioxidant - its strong antioxidant activity points to its potential to target several health conditions. This article covers the antioxidant, UV-light protection, anti-inflammatory and other properties of astaxanthin and its possible role in many human health problems. The research reviewed supports the assumption that protecting body tissues from oxidative damage with daily ingestion of natural astaxanthin might be a practical and beneficial strategy in health management.

Topics: Adjuvants, Immunologic; Administration, Oral; Antioxidants; Arteriosclerosis; beta Carotene; Biological Availability; Blindness; Chlorophyta; Diet Therapy; Humans; Inflammation; Macular Degeneration; Neoplasms; Neurodegenerative Diseases; Nutritional Physiological Phenomena; Photosensitivity Disorders; Radiation-Sensitizing Agents; Species Specificity; Xanthophylls

To report a case of severe ocular quinine toxicity after a suicide attempt and an experimental treatment with high-dose 9-cis beta-carotene.. Interventional case report.. A 59-year-old woman presented with acute bilateral blindness after ingesting high dose (12 g) of quinine sulphate. Her vision was no light perception in either eye, and her pupils were fixed and middilated. Because of limited vision and poor prognosis, she was treated with an experimental rescue therapy of high-dose 9-cis beta-carotene Dunaliella bardawil powder for 3 months, starting 10 days postingestion. Electroretinography measurements showed transient improvement in a-wave amplitudes. The electroretinography b-wave showed only partial transient improvement in the left eye. Overall, the patient's visual acuity improved to 20/33 in the right eye and 20/40 in the left eye, but with extremely constricted visual fields.. Transient improvement in electroretinography measurements was observed under treatment with high-dose 9-cis beta-carotene in ocular quinine toxicity, although no clinical benefit was documented. More research is needed to determine its effect in patients with toxic retinal damage.

Topics: Administration, Oral; Analgesics, Non-Narcotic; beta Carotene; Blindness; Dose-Response Relationship, Drug; Electroretinography; Female; Fluorescein Angiography; Follow-Up Studies; Fundus Oculi; Humans; Middle Aged; Quinine; Retina; Suicide, Attempted; Visual Acuity; Visual Fields; Vitamins

Topics: beta Carotene; Blindness; Clinical Trials as Topic; Contraindications; Dietary Supplements; Drug Labeling; Humans; Lung Neoplasms; Macular Degeneration; Male; Prostatic Neoplasms; Smoking; Zinc

Topics: Africa; beta Carotene; Blindness; Child; Humans; Peru; Solanaceae; Vitamin A Deficiency