Vitamin B12 Deficiency.

U.S. Army Health Clinic, Darmstadt, Germany.
American family physician (Impact Factor: 2.18). 04/2003; 67(5):979-86.
Source: PubMed


Vitamin B12 (cobalamin) deficiency is a common cause of macrocytic anemia and has been implicated in a spectrum of neuropsychiatric disorders. The role of B12 deficiency in hyperhomocysteinemia and the promotion of atherosclerosis is only now being explored. Diagnosis of vitamin B12 deficiency is typically based on measurement of serum vitamin B12 levels; however, about 50 percent of patients with subclinical disease have normal B12 levels. A more sensitive method of screening for vitamin B12 deficiency is measurement of serum methylmalonic acid and homocysteine levels, which are increased early in vitamin B12 deficiency. Use of the Schilling test for detection of pernicious anemia has been supplanted for the most part by serologic testing for parietal cell and intrinsic factor antibodies. Contrary to prevailing medical practice, studies show that supplementation with oral vitamin B12 is a safe and effective treatment for the B12 deficiency state. Even when intrinsic factor is not present to aid in the absorption of vitamin B12 (pernicious anemia) or in other diseases that affect the usual absorption sites in the terminal ileum, oral therapy remains effective.

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    • "The vitamin B12 performs a key role as a coenzyme in the synthesis of DNA, synthesis of neurolipids, and cellular growth. The deficiency of this vitamin can result in megaloblasts (abnormal cell growth, anemia) and longterm deficiency leads to nerve degeneration and irreversible neurological damage (Robert and Brown, 2003). Traditional quantification methods of vitamin B12 within the human body are expensive and require long spans of time, which makes their use impractical for a quick diagnosis that would allow adequate treatment in case of deficiency. "
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    ABSTRACT: This study reports the characterization of the Tetrasphaera duodecadis bacteria and the techniques used therein. In order to evaluate the morphological characteristics of the T. duodecadis bacteria scanning electron microscope (SEM) was used throughout its different growth stages. These microorganisms were grown in vitamin B12 broths with 1% tryptone, 0.2% yeast extract, and 0.1% glucose. The turbidimetric method was employed for the determination of bacterial concentration and growth curve. The SEM results show small agglomerates of 0.8 ± 0.05 µm during the lag phase, and rod-like shapes during the exponential phase with similar shapes in the stationary phase. SCANNING 9999:XX–XX, 2014. © 2014 Wiley Periodicals, Inc.
    Scanning 09/2014; 36(5). DOI:10.1002/sca.21154 · 1.89 Impact Factor
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    • "The deficiency of Vitamin B 12 may cause some disorders such as hematologic, neuropsychiatric and cardiovascular disorders. According to the clinical findings, patients whose blood serum levels of Vitamin B 12 are lower than 200 pg/mL (150 pmol/L) are diagnosed with Vitamin B 12 deficiency [35]. Therefore, the determination of the level of Vitamin B 12 is very important for blood, drugs, dairy products, and fermentation products . "
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    ABSTRACT: In this study, peptide nanostructures from diphenylalanine were synthesized in various solvents with various polarities and characterized with Scanning Electron Microscopy (SEM) and Powder X-ray Diffraction (PXRD) techniques. Formation of peptide nanofibrils, nanovesicles, nanoribbons, and nanotubes was observed in different solvent mediums. In order to investigate the effects of peptide nanotubes (PNT) on electrochemical behavior of disposable pencil graphite electrodes (PGE), electrode surfaces were modified with fabricated peptide nanotubes. Electrochemical activity of the pencil graphite electrode was increased with the deposition of PNTs on the surface. The effects of the solvent type, the peptide nanotube concentration, and the passive adsorption time of peptide nanotubes on pencil graphite electrode were studied. For further electrochemical studies, electrodes were modified for 30 min by immobilizing PNTs, which were prepared in water at 6 mg/mL concentration. Vitamin B12 analyses were performed by the Square Wave (SW) voltammetry method using modified PGEs. The obtained data showed linearity over the range of 0.2 μM and 9.50 μM Vitamin B12 concentration with high sensitivity. Results showed that PNT modified PGEs were highly simple, fast, cost effective, and feasible for the electro-analytical determination of Vitamin B12 in real samples.
    Applied Surface Science 06/2014; 303:37–45. DOI:10.1016/j.apsusc.2014.02.039 · 2.71 Impact Factor
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    • "Moreover, the so-called cubilin receptor, which is found in the entire ileum and not only in the terminal ileum, has also a physiological role in the absorption of vitamin B12 (53–55). Additionally, there is some evidence of the existence of an alternative system, which is obviously independent of the intrinsic factor or the terminal ileum and about 1% of orally administered vitamin B12 is absorbed by an additional, yet unknown, pathway (52, 56, 57). Collectively, current knowledge suggests that the terminal ileum is not the only site of vitamin B12 absorption (56–61). "
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    ABSTRACT: Metabolic disturbances are well-known, but sometimes neglected immediate consequences or late sequelae following urinary diversion (UD) using bowel segments. Whereas subclinical disturbances appear to be quite common, clinically relevant metabolic complications, however, are rare. Exclusion of bowel segments for UD results in loss of absorptive surface for its physiological function. Previous studies demonstrated that at least some of the absorptive and secreting properties of the bowel are preserved when exposed to urine. For each bowel segment typical consequences and complications have been reported. The use of ileal and/or colonic segments may result in hyperchloremic metabolic acidosis, which can be prevented if prophylactic treatment with alkali supplementation is started early. The resection of ileal segments may be responsible for malabsorption of vitamin B12 and bile acids with subsequent neurological and hematological late sequelae as well as potential worsening of the patient's bowel habits. Hence, careful patient and procedure selection, meticulous long-term follow-up, and prophylactic treatment of subclinical acidosis is of paramount importance in the prevention of true metabolic complications.
    Frontiers in Pediatrics 03/2014; 2:15. DOI:10.3389/fped.2014.00015
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