Vitamin interaction

Xanthurenic acid excretion can be caused in the rabbit by a idtamin-E as well as vitamin-Be-deficiency (200). This is more likely to loe due to vitamin interaction than to a direct effect of vitamin E on tryptophan metabolism. 

Uherova, R., Fedorova, N., and Dubravicky, J., The study of vitamin interaction with the reactive constituents of smoking agent. Die Nahrung, 37(1), 85-87, 1993. 

The nutrient sparing effect of antibiotics may result from reduction or elimination of bacteria competing for consumed and available nutrients. It is also recognized that certain bacteria synthesize vitamins (qv), amino acids (qv), or proteins that may be utilized by the host animal. Support of this mode of action is found in the observed nutritional interactions with subtherapeutic use of antibiotics in animal feeds. Protein concentration and digestibiHty, and amino acid composition of consumed proteins may all influence the magnitude of response to feeding antibiotics. Positive effects appear to be largest... 

M. E. Shis, J. A. Olson, and M. Shike, eds.. Modem Nutrition in Health and Disease, 8th ed., Vols. 1 and 2, Lea Eebigher, Phiadelphia, Pa., 1993. Conference on Micronutrient Interactions Vitamins, Minerals andHasyardous KUements, The New York Academy of Sciences, Eeb. 20—22,1980. 

Interaction of vitamin D and its metaboUtes with sex hormones has been demonstrated, particularly ia birds ia which the egg-laying functions combine calcium needs and reproductive activity. The metaboUtes of vitamin D behave as hormones. As such, they play an active role ia the endocrine system, along with other hormones, to maintain the various body functions. Several biological influences of metaboUtes of vitamin D have been studied, including effects related to cancer (193—197), skin diseases (198—201), immunomodulatory effects (202,203), and Alzheimer s disease (204—206) (Fig. 9). 

Factor IX. This factor is dependent on the presence of vitamin K for its activity as a biologicaUy functional procoagulant glycoprotein. Factor IX is converted to its active form by XIa in the classic scheme of the intrinsic pathway. However, it can also be activated via interaction with Factor Xa or the complex Factor III plus Factor VII in the presence of calcium. 

Two techniques for sorption-spectroscopic determination of ascorbic acid have been proposed. The first one is the recovery by silica modified with tetradecyl ammonium nitrate of blue form of molibdophosphoric HPA in the presence of vitamin C. And the second one is the interaction between the ascorbic acid in solution and immobilized on silica ion associate of molibdophosphoric acid with lucigenine. The detection limits of vitamin C are 0.07 and 2.6 mg respectively. The techniques were successfully applied to the determination of ascorbic acid in fmit juices. 

Diugs with metabolic interactions that can enhance the half-life of active compounds. An example of this regimen is the interaction between azole- and vitamin D-deiivatives that inhibit the metabolism of retinoids in skin cells leading to increased intracellular amounts of active RA-isomers. Further study and the identification of novel interactions of this type ofdtug interaction is of great clinical interest since they may decrease the dose of retinoids required for efficacy thereby also reducing the risk of side effects of the retinoids. 

Levodopa interacts with many different drugs. When levodopa is used with phenytoin, reserpine, and papaverine, there is a decrease in response to levodopa The risk of a hypertensive crisis increases when levodopa is used with the monoamine oxidase inhibitors (see Chap. 31). Foods high in pyridoxine (vitamin B6) or vitamin B6 preparations reverse the effect of levodopa However, when carbidopa is used with levodopa, pyridoxine has no effect on the action of levodopa hi fact, when levodopa and carbidopa are given together, pyridoxine may be prescribed to decrease the adverse effects associated with levodopa... 

Sriram K, Misra UK. 1983. Interaction of endosulfan and dietary vitamin A on rat hepatic drug metabolizing enzymes. Acta Vitaminol Enzymol 5 213-218. 

Particular attention is given to the development of new mechanistic biomarker assays and bioassays that can be used as indices of the toxicity of mixtures. These biomarker assays are typically based on toxic mechanisms such as brain acetylcholinesterase inhibition, vitamin K antagonism, thyroxin antagonism, Ah-receptor-mediated toxicity, and interaction with the estrogenic receptor. They can give integrative measures of the toxicity of mixtures of compounds where the components of the mixture share the same mode of action. They can also give evidence of potentiation as well as additive toxicity. 

Russell J et al Interaction between calcium and 1,25-dihydroxy-vitamin D3 in the regulation of preproparathyroid hormone and vitamin D receptor mRNA in avian parathyroids. Endocrinology 1993 132 2639. 

Figure 45-6. Interaction and synergism between antioxidant systems operating in the lipid phase (membranes) of the cell and the aqueous phase (cytosol). (R-,free radical PUFA-00-, peroxyl free radical of polyunsaturated fatty acid in membrane phospholipid PUFA-OOH, hydroperoxy polyunsaturated fatty acid in membrane phospholipid released as hydroperoxy free fatty acid into cytosol by the action of phospholipase Aj PUFA-OH, hydroxy polyunsaturated fatty acid TocOH, vitamin E (a-tocopherol) TocO, free radical of a-tocopherol Se, selenium GSH, reduced glutathione GS-SG, oxidized glutathione, which is returned to the reduced state after reaction with NADPH catalyzed by glutathione reductase PUFA-H, polyunsaturated fatty acid.)...

Figure 4.7. Possibilities for the synthesis of Vitamin K3. The small pore titaninm zeolite TS-1 cannot fit the large naphthalene molecule into its pore system, and thus is effective in this transformation. The larger titanium MTS material is capable of interacting with the molecule, and the desired transformation can take place.

At first glance it may seem that like dissolves like does not apply here. Certainly, none of these complex molecules looks like water, and the resemblance to simple hydrocarbons such as cyclohexane also is remote. Keep in mind, however, that the basis for the principle is that similar compounds dissolve in each other because they have common patterns of intermolecular interactions. Example indicates that alcohols containing large nonpolar segments do not dissolve well in water. We can categorize vitamins similarly by the amounts of their stmctures that can be stabilized by hydrogen bonding to water molecules. 

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