Tissues vitamin

Edes, T. E., Gysbers, D. G., Buckley, C. S., and Thornton, W. H., Jr. (1991). Exposure to the carcinogen benzopyrene depletes tissue vitamin A Beta-carotene prevents depletion. 

Polar molecules are easier to excrete because of their greater solubility in water. For example, upon dissolving in water, they can be excreted through urine. Nonpolar molecules, by contrast, tend to adhere within nonpolar tissues, such as fat tissues. Vitamin A, for example, is a nonpolar molecule that is retained by the body within fat tissues for many months. This is in contrast to polar B-vitamins, which pass out of the body through the urine within a day. 

Vitamin E has been shown, in a wide range of studies, to be capable of affording considerable protection to cells exposed to free radical attack, either from pathological or drug-induced sources. In injured nervous tissue, vitamin E probably exerts its protective effect by scavenging free radicals, stabilizing cellular membranes and quenching the cascade of biochemical events that... 

In intestinal tissue, vitamin E has little or no effect in normoxia. A study [221] using rabbit intestine showed that vitamin E had a weak inhibitory action which was direct and independent of adrenergic or cholinergic nervous influences. In guinea-pig colon, the vitamin was without action in normoxia. In hypoxia, where the spontaneous contractile activity was replaced by quiescence, vitamin E delayed the decline in activity [222], However, once hypoxia had been achieved, vitamin E was able to induce an increase in contractile activity. 

Determination of Vitamin E and Se Levels in Tissues. Vitamin E levels (at total tocopherol) were determined by the spectro-fluorometric method of Taylor, et al. (25). Selenium levels were determined spectrofluorometrically as described by Whetter and Ullrey (24). 

The mechanism of action of U-74006F in antagonizing the development of post-traumatic ischemia is believed to involve an inhibition of oxygen-radical-mediated microvascular lipid peroxidation. This conclusion is based upon the concomitant action of U-74006F to attenuate an injury-induced decline in spinal-tissue vitamin E at the same doses that reduce post-traumatic ischemia [24],... 

Vitamin A is necessary for the light reactions of vision, for normal growth and reproduction, and for differentiation and maintenance of epithelial tissues. Vitamin A is an antioxidant and has anticancer activity. 

Oxidative stress is suggested to play a major role in the pathogenesis of AD. Vitamin C has been regarded as the most important antioxidant in neural tissue. Vitamin C decreases p-amyloid generation and acetylcholinesterase activity and prevents endothelial dysfunction by regulating nitric oxide. Clinical trials with different antioxidants, including vitamin C, yielded confusing results [485],... 

VITAMIN C (L-ascorbic acid) Vitamin C plays an important role as a redox-catalyst in metabolism in teeth, bone, cartilage and parenchyma-tissue. Vitamin C occurs in several fruits such as an rose hips (Cynosbatifructus), Black currant. Sallow-thorn (Hippophae rhamnoides), Citrus-fruits, Paprika, Potato, Cabbage, and Parsley. 

Okayama A, Fun L, Yamatodani A, et al. 1987. Effect of exposure to carbon disulfide on tryptophan metabolism and the tissue vitamin B6 contents of rats. Arch Toxicol 60 450-453. 

Vitamin C may be found in citrus fruits, tomatoes, leafy green vegetables, and potatoes and used to metabolize carbohydrates and used for synthesis of protein, lipids, and collagen. Vitamin C is also required for capillary endothelium and repair of tissues. Vitamin C aids in the absorption of iron and the metabolism of foMc acid. Unlike fat-soluble vitamins, vitamin C is not stored in the body and is excreted in urine. However, high serum levels of vitamin C can result from excessive doses and be excreted without any change. Vitamin C is commercially available as Ascorbicap, Cecon, Cevalin, Solucap C. 

Vitamin E, like other lipids, is digested and absorbed only in the presence of bile. Bile functions as the lipid emulgent and makes absorption of lipids in the intestinal epithelium possible. Vitamin E can be absorbed 30 to 90% while its assimilability amounts to about 30%, the rest being excreted from the organism. In adults, the concentration of a-T in plasma should exceed 30 pmol/L (Biesalski, 1997). A diet rich in vitamin E allows its accumulation in the organism, for example, in the liver, pituitary gland, and adrenals, as well as in adipose and muscular tissues. Vitamin E... 

B. Stores Other Tissues Vitamin A Disposal Rate References... 

Data obtained by Braun and Carle (1943) in analyses of the livers of fetuses aborted after 210-277 days of gestation showed an average tissue vitamin A content of only 1.7 I.U./gm for embryos of stall-fed cows, and 6.6 I.U./gm for fetuses of pasture-fed cows. No vitamin A, or only traces of this compound, were found by Harms (1942b) in analyses of 17 fetal cattle livers. 

The hydroxylated vitamin D derivatives act as hormones in humans and higher animals regulating the absorption of Ca + in the intestine (E 3.1). Reduced hormone levels result in calcium deficiency, which causes rickets. Surplus amounts cause calcification of soft tissues. Vitamin D3 synthesized and stored in certain plants is poisonous to animals (E 5.5.3). 

In tissues, vitamin B12 is converted into the 5 -deox-yadenosyl derivative in a reaction involving cyanoco-... 

The metabolism of ABA in isolated barley aluerone layers follows the ABA PA- DPA pathway that has been shown to exist in many plant tissues [3, 23]. The biological activities of isolated PA and DPA have been tested in this system. Although DPA has little or no biological activity, PA is as active as ABA, i.e. the GAg-induced a-amylase is effectively inhibited by either PA and ABA, but not by DPA [3]. It has been reported that in animal tissues vitamin D has to be metabolized by hydroxylation in order to become biologically active [4]. Thus, the observation that PA is biologically active has raised the question of whether PA is the active component in ABA action. The metabolism from ABA to PA is catalyzed by a cytochrome P450 type monooxygenase with a short-lived intermediate, 6 -hy-droxymethyl ABA [23]. A pretreatment of barley aleurone layers with 10 M ABA for 24 h enhances the tissue s ability to convert [ H]ABA to [ H]PA by 3- to 5-fold... 

In general, the greater the amount of vitamin E fed and/or length of feeding period, the higher the tissue concentration of a-tocopherol (Table 8.2). Plasma levels of a-tocopherol are used to monitor intake of the vitamin, but are considered an adequate indicator of tissue vitamin status only during steady-state conditions (Arnold et al., 1992b). Within plasma, vitamin E is associated with lipoproteins, while in cells it is found as part of biomembranes. Traber and Kayden (1987) have reported that in human adipose tissue, tocopherol is associated primarily with adipocyte contents and not the plasmalemma. 

Valente, E., Scott, J.M., Ueland, P.M., Cunningham, C., Casey, M., and Molloy, A.M., 2011. Diagnostic accuracy of holotranscobalamin, methylmalonic acid, serum cobalamin, and other indicators of tissue vitamin B12 status in the elderly. Clinical Chemistry. 57 856-863. 

Tsao, C. S., Leung, P. Y., and Young, M., 1987, Effect of dietary ascorbic acid intake on tissue vitamin C in mice, J. Nutr. 117 291-297. 

In summary, the case-control studies discussed above suggest that plasma or tissue vitamin C levels are lower among patients with CVD however, it is difficult to infer causal relationships from these studies due to the several inherent weaknesses of this methodology. In case-control studies, selection and recall bias as well as change in dietary habits after disease onset may have an impact on risk estimates, since exposure status is ascertained after disease occurrence. 

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