Vitamin effect

The antioxidant properties of vitamins C and E can inhibit the formation of some carcinogens. The antioxidant vitamins have been studied as cancer chemopre-ventive agents for many cancer types, including gastrointestinal and ovarian cancers. However, data are not sufficient to draw conclusions about the vitamins effects on human cancers. 

Vitamins, effect on stability of organisms to ionizing radiation 90KFZ(1)4. 

Another B complex vitamin effected is Be (pyridoxine). This vitamin is required for transaminations ana decarboxylations, two processes of major importance in the metabolism of the central nervous tissue. B0 dehciency occurs in many bodily disorders, dermatitis, anemia, and epileptic seizures, to name some. In alcoholics it is most often seen in delirium tremens (an alcohol withdrawal symptom). 

Other B vitamins effected are Niacin (nicotinic acid), pantothenic acid, B 2 (cobalamin) and B2 (Riboflavin). Niacin in massive doses is used in the treatment of schizophrenia. A deficiency of this vitamin (also known as B can result in many of the same neurological problems asB0. Pantothenic acid in conjunction with other vitamins aids in many enzymic duties. Deficiencies in Bio lead to easy fatigue, and a thousand other related problems. The last, riboflavin, is affected quite differently. Ethanol seems to cause the body to hoard tfiis vitamin the exchange hardly seems fair, though. 

We may perhaps remember that scarcely ten years have elapsed since the time vohen many research scientists doubted the material specificity of the vitamins, and were of the opinion that a special state of matter, a special colloidal character, was the cause of the peculiar vitamin effects which had been observed. 

Some substances referred to as provitamins do not show physiological effects themselves but can serve as precursors from which the body can synthesise vitamins. A provitamin of vitamin Aj (retinol), for example, is -carotene. The term vitamin sometimes also includes other biologically active substances whose vitamin effect has not been demonstrated rehably or substances needed by other organisms, for example by microorganisms. 

In order to investigate further the specificity of these vitamin effects, these studies were extended to include purified diphtheria toxoid as the antigen. Again, the marked impairment of antibody response in various vitamin deficiency states was evident (Pruzansky and Axelrod, 1955). With the exception of the deleterious action of a vitamin D deficiency, the trends observed with diphtheria toxoid were similar to those noted when red blood cells served as the antigen. Later studies clearly demonstrated the inhibitory effects of the nutritional deficiency states upon the anamnestic process, with impairment of the secondary response being most pronounced (Figure 1.) (Axelrod, 1958). The conclusion was drawn that the successful attainment and maintenance of a satisfactory anamnestic response to diphtheria toxoid in the albino rat requires a state of adequate nutriture during both the primary and secondary phases of this process. 

In the last 20 years much attention has been paid to the determination of vitamins in foodstuffs due to their nutritional implications and the need for an adequate quality control of food products. Vitamin analysis in these matrices is difficult due to the high variability in their composition and the great number of components, which implies the risk of interference and the low vitamin content. Additional problems are the existence of different chemical compounds with vitamin effects and their stability influenced by light, heat, oxygen, or pH conditions. The development of new analytical techniques has led in recent years to analytical methods that are more rapid, accurate, and sensitive. 

Carotenoids absorb visible light (Section 13 21) and dissipate its energy as heat thereby protecting the organism from any potentially harmful effects associated with sunlight induced photochemistry They are also indirectly involved m the chemistry of vision owing to the fact that p carotene is the biosynthetic precursor of vitamin A also known as retinol a key substance m the visual process... 

Vitha, M. F. Carr, P. W. A Laboratory Exercise in Statistical Analysis of Data, /. Chem. Educ. 1997, 74, 998-1000. Students determine the average weight of vitamin E pills using several different methods (one at a time, in sets of ten pills, and in sets of 100 pills). The data collected by the class are pooled together, plotted as histograms, and compared with results predicted by a normal distribution. The histograms and standard deviations for the pooled data also show the effect of sample size on the standard error of the mean. 

Procedure. A vitamin B complex tablet Is crushed and placed In a beaker with 20.00 mL of a 50% v/v methanol solution that Is 20 mM In sodium tetraborate and contains 100.0 ppm of o-ethoxybenzamIde. After mixing for 2 min to ensure that the B vitamins are dissolved, a 5.00-mL portion Is passed through a 0.45- xm filter to remove Insoluble binders. An approximately 4-nL sample Is loaded Into a 50- xm Internal diameter capillary column. For CZE the capillary column contains a 20 mM pH 9 sodium tetraborate/sodlum dIhydrogen phosphate buffer. For MEKC the buffer Is also 150 mM In sodium dodecylsulfate. A 40-kV/m electric field Is used to effect both the CZE and MEKC separations. 

Antibiotics (qv) have been fed at subtherapeutic levels to promote mminant animal growth. Possible reasons for the observed growth include decreased activity of microbes having a pathogenic effect on the animal, decreased production of microbial toxins, decreased microbial destmction of essential nutrients, increased vitamin synthesis or synthesis of other growth factors, and increased nutrient absorption because of a thinner intestinal wall... 

Sulfur Dioxide and Sulfites. Sulfur dioxide [7446-09-5], SO2, sodium bisulfite [15181-46-1], NaHSO, and sodium metabisulfite [23134-05-6] ate effective against molds, bacteria, and certain strains of yeast. The wine industry represents the largest user of sulfites, because the compounds do not affect the yeast needed for fermentation. Other appHcations include dehydrated fmits and vegetables, fmit juices, symps and concentrates, and fresh shrimp (79). Sulfites ate destmctive to thiamin, and cannot be used in foods, such as certain baked goods, that ate important sources of this vitamin. 

Of the water-soluble vitamins, intakes of nicotinic acid [59-67-6] on the order of 10 to 30 times the recommended daily allowance (RE)A) have been shown to cause flushing, headache, nausea, and moderate lowering of semm cholesterol with concurrent increases in semm glucose. Toxic levels of foHc acid [59-30-3] are ca 20 mg/d in infants, and probably approach 400 mg/d in adults. The body seems able to tolerate very large intakes of ascorbic acid [50-81-7] (vitamin C) without iH effect, but levels in excess of 9 g/d have been reported to cause increases in urinary oxaHc acid excretion. Urinary and blood uric acid also rise as a result of high intakes of ascorbic acid, and these factors may increase the tendency for formation of kidney or bladder stones. AH other water-soluble vitamins possess an even wider margin of safety and present no practical problem (82). 

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... 

Lead is toxic to the kidney, cardiovascular system, developiag red blood cells, and the nervous system. The toxicity of lead to the kidney is manifested by chronic nephropathy and appears to result from long-term, relatively high dose exposure to lead. It appears that the toxicity of lead to the kidney results from effects on the cells lining the proximal tubules. Lead inhibits the metaboHc activation of vitamin D in these cells, and induces the formation of dense lead—protein complexes, causing a progressive destmction of the proximal tubules (13). Lead has been impHcated in causing hypertension as a result of a direct action on vascular smooth muscle as well as the toxic effects on the kidneys (12,13). 

Inhibition of nitrosation is generally accompHshed by substances that compete effectively for the active nitrosating iatermediate. /V-Nitrosamine formation in vitro can be inhibited by ascorbic acid [50-81-7] (vitamin C) and a-tocopherol [59-02-9] (vitamin E) (61,62), as well as by several other classes of compounds including pyrroles, phenols, and a2iridines (63—65). Inhibition of iatragastric nitrosation ia humans by ascorbic acid and by foods such as fmit and vegetable juices or food extracts has been reported ia several instances (26,66,67). 

The i j -configuration of the 6,7-double bond in pre-vitamin D is critical to its subsequent thermal rearrangement to the active vitamin. A photochemical isomerization of pre-vitamin D to yield the inactive trans-isoTnen occurs under conditions of synthesis, and is especially detrimental if there is a significant short wavelength component, eg, 254 nm, to the radiation continuum used to effect the synthesis. This side reaction reduces overall yield of the process and limits conversion yields to ca 60% (71). Photochemical reconversion of the inactive side product, tachysterol, to pre-vitamin D allows recovery of the product which would otherwise be lost, and improves economics of the overall process (70). 

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