Toxicology Vitamin

Toxicology Vitamin A hypervitaminosis can lead to clinical symptoms such as headache, nausea, in chronic cases disturbances of sleep, loss of appetite, loss of hair, bone swellings in the limbs however, all symptoms disappear when the consumption of vitamin A is reduced. Acute poisonings have been observed in, e.g., polar explorers after consumption of the extremely vitamin A,-rich polar bear liver. The metabolite of R., vitamin A acid (retinoic acid, tretinoin, C20H28O3, Mr 316.44, mp. 180-182 °C) can cause malformations and thus pregnant women should not consume more than 3.3 mg of vitamin A] per day Synthesis R. was obtained in the past from fish oils, which have contents of up to 17%, while it is now mostly produced synthetically . ... 

Horwitt MK (1972) Vitamin B2 pharmacology and toxicology. Vitamins 5 85-87 Hovding G (1968) Anaphylactic reaction after injection of vitamin Bi2- Br Med J 610 102 James J, Warin RP (1971) Sensitivity to cyanocobalamin and hydroxocobalamin. Br Med J 5756 262... 

Reported cases of vitamin toxicity owing to overdose are usually associated with increased over-the-counter availabiHty of supplemental vitamins and indiscriminate supplementation. The misconception that if a Httle is good a lot is better has compounded toxicological problems with the vitamins. Eat-soluble vitamins tend to accumulate in the body with relatively inactive mechanism for excretion and cause greater toxicological difficulties than do water-soluble vitamins. 

One of the few phytochemicals that has been subjected to the rigorous testing procedures required by food safety authorities is P-carotene, a naturally-occurring carotenoid that is also a pre-cursor of vitamin A in humans. It is increasingly used as a food colour since the food product can be claimed to contain all natural ingredients. For this reason, detailed toxicological studies were undertaken that enabled the Joint FAO/WHO Expert Committee for Food Additives (JECFA) to set an ADI of 0-5 mg/kg/bw/day based on a NOAEL of 50 mg/day and the application of an uncertainty factor of 10 (JECFA, 1974). This low factor was used because it was argued that the compound occurred naturally in food, that its use as a food additive would not lead to a substantial increase in the total amount normally consumed, and that there had been no reports of adverse effects in humans. The ADI would correspond to an acceptable intake in humans of up to 350 mg/day. 

Shvedova, A.A. et al. (2007) Vitamin E deficiency enhances pulmonary inflammatory response and oxidative stress induced by single-walled carbon nanotubes in C57BL/6 mice. Toxicology and Applied Pharmacology, 221 (3), 339-348. 

Du Toit R, Volsteedt Y and Apostolides Z. 2001. Comparison of the antioxidant content of fruits, vegetables and teas measured as vitamin C equivalents. Toxicology 166(l-2) 63-69. 

Much of the toxicological interest in cyanide relating to mammals has focused on its rapid lethal action. However, its most widely distributed toxicologic problems are due to its toxicity from dietary, industrial, and environmental factors (Way 1981, 1984 Gee 1987 Marrs and Ballantyne 1987 Eisler 1991). Chronic exposure to cyanide is correlated with specific human diseases Nigerian nutritional neuropathy, Leber s optical atrophy, retrobulbar neuritis, pernicious anemia, tobacco amblyopia, cretinism, and ataxic tropical neuropathy (Towill etal. 1978 Way 1981 Sprine etal. 1982 Beminger et al. 1989 Ukhun and Dibie 1989). The effects of chronic cyanide intoxication are confounded by various nutritional factors, such as dietary deficiencies of sulfur-containing amino acids, proteins, and water-soluble vitamins (Way 1981). 

Toxicology. Pindone is a vitamin K antagonist and causes inhibition of prothrombin formation, which results in hemorrhage. 

This chapter focuses on the pharmacological and toxicological properties of vitamins. 

Deficiency syndromes of Zn, Cu, Cr, Se and Mo have occurred in patients on total parenteral nutrition (TPN). There is still much research to be done in assessing the nutritional status of many elements and understanding their metabolism, so that normal dietary intake may be supplemented for health benefits. Table 2 is a summary of the amounts required, the functions and the nutritional (usually dietary) imbalances in humans, where known, of the essential trace elements.31-33 (Note that this summary does not attempt to include imbalances related to environmental toxicology and occupational hazards.) Several trace elements have important functions in the immune system. Some are associated with nucleic acid. Others have structural roles, such as Si in cartilage, F and Zn in bone. They may be parts of vitamins, such as Co in vitamin B12, or hormones, such as iodine in thyroid hormones, Zn and Cr have a role in the synthesis and action of insulin.31-33... 

Subakir SB, Setiadi E, Affandi B, Pringgoutomo S, Freisleben HJ. Benefits of vitamin E supplementation to Norplant users—in vitro and in vivo studies. Toxicology 2000 148(2-3) 173-8. 

Carotenoids are used to an increasing extent for the coloration of foodstuffs and animal feedstuffs, since, as natural constituents of many foodstuffs, they have been part of the human diet for thousands of years and are thus toxicologically acceptable8. The precursors from the vitamin A and carotenoid syntheses also include some of the important fragrances which are used in the perfume industry. In addition, this chemistry led to the synthesis of a number of other interesting flavors and fragrances. 

Brouwer A and van den Berg KJ (1986) Binding of a metabolite of 3,4,3, 4 -tetra-chlorobiphenyl to transthyretin reduces serum vitamin A transport by inhibiting the formation of the protein complex carrying both retinol and thyroxin. Toxicology and Applied Pharmacology 85,301-12. 

Guyton KZ, Kensler TW, and Posner GH (2001) Cancer chemoprevention using natural vitamin D and synthetic tLmdogs. Annual Reviews of Pharmacology and Toxicology 41, 421-42. 

Miller RK, Hendrickx AG, Mills JL, Hummler H,and Wiegand UW (1998) Periconcep-tional vitamin A use how much is teratogenic Reproductive Toxicology 12, 75-... 

Work on vitamin K had three independent beginnings. They were toxicological, nutritional, and biochemical in nature. 

Fig. 1 Analysis of vitamin administered in dogs by the intravenous or intrarectal route (R Berny, S. Viallet, F. Buron-fosse, and G. Lorgue, European Association of Veterinary Pharmacology and Toxicology, Madrid 6-10 July, 1997).

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