Cyanocobalamin deficiency

Nutritional Folate deficiency Iron deficiency Vitamin Bi (thiamine) deficiency Vitamin B2 (riboflavin) deficiency Vitamin Bg (pyridoxine) deficiency Vitamin B12 (cyanocobalamin) deficiency... 

The observation that the psychosis associated with pernicious anemia may manifest itself in a patient for several years before the other manifestations of this disease become noticeable has a reasonable explanation the functioning of the brain and nervous tissue is probably more sensitively dependent on molecular composition than is that of other organs and tissues. The observed high incidence of cyanocobalamin deficiency in patients admitted to a mental hospital, mentioned above, suggests that mental disease may rather often be the result of this deficiency, and further suggests that other deficiencies in vital substances may be wholly or partly responsible for many cases of mental illness. 

Cobalt is one of twenty-seven known elements essential to humans (28) (see Mineral NUTRIENTS). It is an integral part of the cyanocobalamin [68-19-9] molecule, ie, vitamin B 2> only documented biochemically active cobalt component in humans (29,30) (see Vitamins, VITAMIN Vitamin B 2 is not synthesized by animals or higher plants, rather the primary source is bacterial flora in the digestive system of sheep and cattle (8). Except for humans, nonmminants do not appear to requite cobalt. Humans have between 2 and 5 mg of vitamin B22, and deficiency results in the development of pernicious anemia. The wasting disease in sheep and cattle is known as bush sickness in New Zealand, salt sickness in Florida, pine sickness in Scotland, and coast disease in AustraUa. These are essentially the same symptomatically, and are caused by cobalt deficiency. Symptoms include initial lack of appetite followed by scaliness of skin, lack of coordination, loss of flesh, pale mucous membranes, and retarded growth. The total laboratory synthesis of vitamin B 2 was completed in 65—70 steps over a period of eleven years (31). The complex stmcture was reported by Dorothy Crowfoot-Hodgkin in 1961 (32) for which she was awarded a Nobel prize in 1964. 

Vitamin B12 (cyanocobalamin) is used to treat a vitamin B12 deficiency. A vitamin B12 deficiency may be seen in ... 

Cobalt is present in animals in vitamin B12 (cyanocobalamine) and thus is essential for humans (Thunus and Lejeune 1994). The determination of Co has little significance for the diagnosis of deficiency of cyanocobalamine. Instead, cyanocobalamine itself must be determined in serum. The determination of methyl malonic acid in urine seems more reliable (McCann et al. 1996). 

What is the best evidence cited that the anemia is due to a primary deficiency of cyanocobalamin (Bjj) ... 

The name vitamin B12 indicates a group of cobalt-containing corrinoids, also described as cobala-mins. Hydroxycobalamin (HOCbl), adenosylcobalamin (AdoCbl), and methylcobalamin (MeCbl) are the natural occurring forms. Instead, cyanocobalamin (Figure 19.20) is the commercially available form used for supplements and food fortification, thanks to its greater relative stability. Occasionally, sulfitocobalmin can occur in processed foods. Vitamin B,2 functions as a coenzyme and it is linked to human growth, cell development, and is involved in metabolism of certain amino acids. Vitamin B12 is present mainly in meat and diary foods, therefore a deficiency can occur in... 

Cyanocobalamin and the derivative hydroxo-cobalamin, given IM or deep subcutaneously, are indicated for treating vitamin B12 deficiency. Only in strict vegetarians oral preparations may be effective. Oral preparations with added intrinsic factor mostly are not reliably in patients with pernicious anemia. More than half the dose of cyanocobalamin injected is excreted in the urine within 48 hours and the therapeutic advantages of doses higher than 100 pg are questionable because of this rapid eiimination. As... 

Cyanocobalamin, or vitamin B12, is in small amounts required for red blood cell production and for the formation of nucleoproteins and proteins. It is also needed for the proper functioning of the nervous system. Folic acid supplements can correct the anemia associated with vitamin B12 deflciency. Unfortunately, folic acid will not correct changes in the nervous system that result from vitamin B12 deficiency. Vitamin B12 is only found in animal sources such as liver and other organs. Some vitamin B12 is obtained from fish, eggs and milk. Folic acid and cyanocobalamin have been discussed in more detail in Chapter 22. 

Severe cyanocobalamin (vitamin B12) deficiency results in pernicious anemia that is characterized by megaloblastic anemia and neuropathies. The symptoms of this deficiency can be masked by high intake of folate. Vitamin B12 is recycled by an effective enterohep-atic circulation and thus has a very long half-hfe. Absorption of vitamin B12 from the gastrointestinal tract requires the presence of gastric intrinsic factor. This factor binds to the vitamin, forming a complex that... 

Cyanocobalamin A cofactor required for essential enzymatic reactions that form tetrahydrofolate, convert homocysteine to methionine, and metabolize l-methylmalonyl-CoA Adequate supplies are required for amino acid and fatty acid metabolism, and DNA synthesis Treatment of vitamin B12 deficiency, which manifests as megaloblastic anemia and is the basis of pernicious anemia Parenteral vitamin B12 is required for pernicious anemia and other malabsorption syndromes Toxicity No toxicity associated with excess vitamin B12... 

Acid is important in releasing vitamin B12 from food. A minor reduction in oral cyanocobalamin absorption occurs during proton pump inhibition, potentially leading to subnormal Bi2 levels with prolonged therapy. Acid also promotes absorption of food-bound minerals (iron, calcium, zinc) however, no mineral deficiencies have been reported with proton pump inhibitor therapy. 

Another problem associated with saturation analysis is that abnormally low results may be obtained unless cyanide is present when the vitamin is freed from its binder. It appears that forms other than cyanocobalamin are difficult to separate completely from the binding protein. Early studies that failed to recognize this not infrequently found that results from patients with pernicious anemia gave negative values (R9). A recent study by Brown et al. (B6) examined the effect of varying the concentration of cyanide used in the test. They found that an excess of cyanide resulted in a significant increase in apparent vitamin B12 levels in sera from patients who were deficient in the vitamin, but it had little effect on sera from normal patients. They found the mean of 12 vitamin B12-deficient sera to be 49 ng/liter when 3 mg/liter of cyanide was used in the extraction mixture, 104 ng/liter in the presence of 30 mg/liter of cyanide, and 196 ng/liter when 300 mg/liter of cyanide was used. The authors emphasized that cyanide was necessary to convert all of the several forms of vitamin B12 present in serum to cyanocobalamin but warned that the concentration should not be greater than 5 mg/liter. 

K2. Katz, J. H., diMase, J., and Donaldson, R. M., Simultaneous administration of gastric juice bound and free radioactive cyanocobalamins rapid procedure for differentiating between intrinsic factor deficiency and other causes of vitamin B12 malabsorption. J. Lab. Clin. Med. 61, 266-271 (1963). 

Vitamin B,2 (cyanocobalamin) Vitamin C—large doses Precipitate B,2 deficiency... 

In the setting of established B12 deficiency, treatment is usually by parenteral injection, with 1000 tg given daily for the first 5 days. Thereafter, cyanocobalamin (1000 tg) is given monthly by intramuscular or deep subcutaneous injection. While orally administered drug is not recommended in most patients who have a B12 deficiency due to malnutrition or achlorhydria (failure to release food-bound B12), 1000 jig oral vitamin B12 can be administered daily. A... 

Cyanocobalamine is a component of several coenzymes and has an effect on nucleic acid formation through its action in cycling 5-methyl-tetrahydrofolate back into the folate pool. The most important dietary sources of the vitamin are animal products. Vitamin Bl2 is also produced by many microorganisms. It is not surprising that vitamin B12 deficiency of dietary origin only occurs in vegetarians. 

VITAMIN B 12 DEFICIENCY/PERNICIOUS ANEMIA Vitamin B 12 (Cyanocobalamin)... 

Vitamin B]2, cyanocobalamin, is essential for human nutrition. It is concentrated in animal tissue but not in higher plants. Although nutritional requirements for the vitamin are quite low, people who abstain completely from animal products may develop a deficiency anemia. Cyanocobalamin is the form used in vitamin supplements. It contains 4.34% cobalt by mass. Calculate the molar mass of cyanocobalamin, assuming that there is one atom of cobalt in every molecule of cyanocobalamin. 

Deficiency of cyanocobalamin, or vitamin B12, can result in reduced visual acuity secondary to optic nerve dysfunction. Causes range from malabsorption to alcohol abuse.Treatment is with oral (1,000 to 2,000 meg daily)... 

After documenting a serum vitamin B12 deficiency, the patient should receive 300 mg oral thiamine each week and 1,000 g intramuscular hydroxocobalamin each week for 10 weeks.The sooner this therapy begins, the better the prognosis. The hydroxocobalamin fc>rm of vitamin B12 appears to be more effective than cyanocobalamin. In terms of recovery from the amblyopia, cessation of smoking or drinking does not appear to produce remission unless the patient concurrently improves their diet.Thus it is unnecessary and, in practice, difficult to persuade patients who are habitual abusers of tobacco and alcohol to stop the use of such agents. Improvement of dietary status seems to be the most important factor in recovery. 

Although the water-soluble vitamins are structurally diverse, they are put in a general class to distinguish them from the lipid-soluble vitamins. This cla.ss includes the B-complex vitamins and ascorbic acid (vitamin C). The term B-complex vitamins usually refers to thiamine, riboflavin, pyridoxine. nicotinic acid, pantothenic acid, hiotin. cyanocobalamin. and folic acid. Dietary deficiencies of any of the B vitamins commonly are complicated by deftciencies of another mem-ber(s) of the group,. so treatment with B-complex preparations is usually indicated. 

Vitamin Bij (cyanocobalamin extrinsic factor) is required in folate metabolism for DNA synthesis, and a deficiency leads to pernicious anaemia. It is used to supplement the diet after certain operations that remove the site of production of intrinsic factor, such as total gastrectomy. Deficiency causes megaloblastic haemopoiesis in which there is a marked disorder of formation of erythroblasts, and can be rectified by giving hydroxocobalamin. 

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