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Cobalamin Status (Holo-Transcobalamin, Methylmalonic Acid) and Folate as Determinants of Homocysteine Concentration Concern has emerged in America about subtle cobalamin (Cbl; vitamin B12) deficiency, especially in at-risk population groups such as the elderly and vegetarians. An optimal test to diagnose vitamin B12 deficiency is still not available. The determination of total serum vitamin B12 has a low diagnostic accuracy. Measurements of homocysteine (HCY) and methylmalonic acid (MMA) have shown more specificity and sensitivity for subnormal Cbl status, but have disadvantages. HCY, for example, is also increased in folate and vitamin B6 deficiencies, as well as in renal insufficiency; in addition, MMA is expensive to measure, and it, too, increases in renal insufficiency. To improve specificity and sensitivity in diagnosis of vitamin B12 deficiency, holo-transcobalamin (holoTC) assays have been introduced. Because only transcobalamin II promotes the specific cellular uptake of Cbl, the Cbl subfraction attached to transcobalamin II represents the biologically active vitamin B12 fraction. Our previous observations in Syrian individuals revealed a high prevalence of Cbl deficiency ( 49%) when we used MMA as a metabolic marker for Cbl status. The present work was undertaken to further investigate the role of Cbl and folate status as determinants of hyperhomocysteinemia in Syrians. We studied 222 patients [mean (SD) age, 52 years; 192 males and 30 females] with angiographically defined stenosis 50% in at least one major coronary artery. Exclusion criteria included recent myocardial infarction (3 months), acute diseases, and vitamin usage. Blood samples were collected 1 day before the angiography, and the angiography results were followed after that. The control group included 101 apparently healthy non-vitamin users and 10 individuals (7 males and 3 females) who had no stenosis [mean (SD) control age, 46 years; total of 66 males and 45 females]. Only individual with creatinine concentrations within reference values were eligible for this study. Seventy-one percent of patients were hypertensive vs 25% of controls, 32% of patients had diabetes vs 11% of controls, and 23% of patients had never smoked vs 42% of controls. All participants gave informed consent………..(report truncated).
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NewsComing Soon ! The full video recording of the Euromedlab 2007 Active B12 workshop will be available in the next few weeks, register for your copy.
Live CME Web Conference on vitamin B12 deficiency, Prof. Ralph Green, Dec 13th 2007, register now. Meetings
8-11 December, 2007 |
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