The Plasma Clearance and Urinary Excretion of Parenterally Administered 58Co B12

Abstract Intravenous injections of 1.5 µg. of 58Co B12 were given to subjects with normal serum B12 concentrations, to patients with vitamin B12 deficiency and to patients with chronic myelocytic leukemia. The rate of plasma clearance of radioactivity after this dose was slowest in patients with chronic myelocytic leukemia and patients with pernicious anemia in severe relapse. In patients with vitamin B12 deficiency, serum B12 concentrations were estimated microbiologically at frequent intervals after the injection. There was a good correlation between the results obtained by microbiological assay and as calculated from plasma radioactivity. Significant differences were not observed between the urinary excretion of radioactivity by normal subjects and patients with B12 deficiency.

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Identification of the Vitamin B12-Binding Protein in the Serum of Normals and of Patients with Chronic Myelocytic Leukemia

Blood ◽

10.1182/blood.v13.8.740.740 ◽

1958 ◽

Vol 13 (8) ◽

pp. 740-747 ◽

Cited By ~ 47

Author(s):

ROBERT S. MENDELSOHN ◽

DONALD M. WATKIN ◽

ANN P. HORBETT ◽

JOHN L. FAHEY

Keyword(s):

Vitamin B12 ◽

Binding Protein ◽

Qualitative Difference ◽

Normal Subjects ◽

Paper Electrophoresis ◽

Normal Serum ◽

Chronic Myelocytic Leukemia ◽

Myelocytic Leukemia ◽

Abnormal Metabolism

Abstract Vitamin B12-binding proteins in the serum of normal subjects and of patients with chronic myelocytic leukemia have been compared. The in-vivo-bound B12 was utilized to identify the binding protein. Column protein chromatography and block and paper electrophoresis were employed individually and in combination to characterize the B12-binding protein. B12 was found to be bound primarily to an alpha-l globulin in both normal individuals and in patients with chronic myelocytic leukemia. No qualitative difference was found in these proteins. The increased amounts of B12-binding protein in the serum of patients with chronic myelocytic leukemia would seem to be attributable to abnormal metabolism of the same protein that binds B12 in normal serum.

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The Effect of Vitamin B12 Deficiency on Methylfolate Metabolism and Pteroylpolyglutamate Synthesis in Human Cells

Clinical Science ◽

10.1042/cs0470617 ◽

1974 ◽

Vol 47 (6) ◽

pp. 617-630

Author(s):

A. Lavoie ◽

E. Tripp ◽

A. V. Hoffbrand

Keyword(s):

Folic Acid ◽

Vitamin B12 ◽

Direct Effect ◽

Vitamin B12 Deficiency ◽

Pernicious Anaemia ◽

Normal Subjects ◽

Normal Cells ◽

Methyl Group ◽

Consistent Effect ◽

B12 Deficiency

1. The uptake of 14C from [methyl-14C]methyItetrahydrofolate was significantly reduced in the phytohaemagglutinin (PHA)-stimulated lymphocytes from nine patients with untreated pernicious anaemia compared with the uptake in seven normal subjects. 2. The uptake of 14C from [14C]methyltetrahydrofolate by the lymphocytes from seven of the patients with pernicious anaemia was consistently increased by addition of vitamin B12in vitro. 3. The proportion of 14C taken up from [14C]methyltetrahydrofolate transferred to non-folate compounds was found to be significantly reduced in the PHA-stimulated lymphocytes from nine patients with untreated pernicious anaemia compared with the proportion transferred in the PHA-stimulated lymphocytes from seven normal subjects. Addition of vitamin B12in vitro consistently increased the transfer in vitamin B12-deficient cells but had no consistent effect in normal cells. 4. Normal and vitamin B12-deficient PHA-stimulated lymphocytes took up [3H]folic acid and after 72 h incubation converted this largely into pteroylpolyglutamate forms. 5. The proportion of labelled lymphocyte folate as pteroylpolyglutamate after incubation with [3H]folic acid was the same in vitamin B12-deficient as in normal lymphocytes and the proportion of pteroylpolyglutamates formed in vitamin B12-deficient lymphocytes was unaffected by addition of vitamin B12in vitro. 6. No radioactivity could be decteted in pteroylpolyglutamates after incubating normal PHA-stimulated lymphocytes with [14C]methyltetrahydrofolate for 72 h, suggesting that pteroylpolyglutamate forms of folate cannot be made directly from methyltetrahydrofolate. 7. These results are consistent with the ‘methyltetrahydrofolate trap’ hypothesis in vitamin B12 deficiency. It is suggested that reduced synthesis of pteroylpolyglutamates reported by others in vitamin B12-deficient cells may be secondary to the failure of removal of the methyl group from methyltetrahydrofolate rather than to a direct effect of vitamin B12 deficiency on the enzyme responsible for pteroylpolyglutamate synthesis. 8. Reduced entry of methyltetrahydrofolate into vitamin B12-deficient cells may be secondary to failure of conversion of this compound into tetrahydrofolate.

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Factors affecting formiminoglutamic acid excretion in vitamin B12 deficiency

Biochemical Journal ◽

10.1042/bj1160681 ◽

1970 ◽

Vol 116 (4) ◽

pp. 681-688 ◽

Cited By ~ 1

Author(s):

Hedley R. Marston ◽

Shirley H. Allen

Keyword(s):

Urinary Excretion ◽

Vitamin B12 ◽

Vitamin B12 Deficiency ◽

Acid Excretion ◽

Factors Affecting ◽

Methyl Donors ◽

Pteroylglutamic Acid ◽

B12 Deficiency ◽

Acid Status

1. Formiminoglutamic acid, a product of the catabolism of histidine, is excreted in abnormally large amounts in the urines of vitamin B12-deficient rats and of vitamin B12-deficient sheep; the excretion is reduced to negligible amounts after administration of vitamin B12. 2. After administration of certain methyl donors to vitamin B12-deficient rats or sheep urinary excretion of formiminoglutamic acid is temporarily decreased. 3. Irrespective of the pteroylglutamic acid status of the animals neither vitamin B12-deficient rats nor vitamin B12-deficient sheep have the ability to deal efficiently with histidine. 4. In sheep, urinary excretion of formiminoglutamic acid is increased after administration of aminopterin; treatment with pteroylglutamic acid restores the ability of the animal to deal with the catabolic products of histidine. 5. The possible functions of vitamin B12 and methionine in relieving a virtual deficiency of pteroylglutamic acid are discussed.

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Differentiation between Vitamin B12—deficient and Folic Acid—deficient Megaloblastic Anemias with C14—Histidine

Blood ◽

10.1182/blood.v21.4.447.447 ◽

1963 ◽

Vol 21 (4) ◽

pp. 447-461 ◽

Cited By ~ 22

Author(s):

MATHEWS B. FISH ◽

MYRON POLLYCOVE ◽

THOMAS V. FEICHTMEIR

Keyword(s):

Folic Acid ◽

Vitamin B12 ◽

Specific Activity ◽

Megaloblastic Anemia ◽

Vitamin B12 Deficiency ◽

Normal Subjects ◽

Intermediary Metabolism ◽

Folic Acid Deficiency ◽

Acid Deficiency ◽

B12 Deficiency

Abstract Intermediary metabolism of the monocarbon pool and histidine in normal subjects and patients with megaloblastic anemia was studied by continuous measurement of pulmonary excretion of C14O2 and urinary excretion of C14 after injection of L-histidine-2(ring)-C14. Cumulative pulmonary and renal excretion of C14 for 1 month by two normal subjects approximates 45 per cent of the amount injected. Within 4 months after injection of the dose used in this study, the resultant average tissue radiation decreases below the average natural terrestrial and cosmic radiation level. Simultaneous determination of two parameters, (1) cumulative 1-hour pulmonary C14 excretion and (2) the time of occurrence of maximum C14O2specific activity (Tmax), may permit rapid and unequivocal differentiation between folic acid deficiency and vitamin B12 deficiency in the pathogenesis of megaloblastic anemia. Folio acid deficiency results in marked diminution of pulmonary C14 excretion (approximately 0.1 per cent of injection C14 in 1 hour) and marked prolongation of C14O2-specific activity Tmax (approximately 3 hours), while both parameters are normal (approximately 1 per cent and less than 1 hour, respectively) in patients with vitamin B12 deficiency and megaloblastic anemia. Measurement during periods of reticulocyte response to either folio acid or vitamin B12 demonstrate normal C14O2-specific activity Tmax but decreased pulmonary C14 excretion. These observations suggest that prolongation of C14O2-specific activity Tmax is a sensitive index of folic acid deficiency or block and that if Tmax is normal, pulmonary C14 excretion is a sensitive index of the relative partition of the active monocarbon pool between pathways for oxidation and pathways for nucleic acid synthesis. This type of breath analysis seems to provide a quantitative dynamic representation of metabolic function which may be particularly useful in differentiating between the alterations of intermediary metabolism that occur in patients with folic acid-deficient megaloblastic anemia and in patients with vitamin B12-deficient megaloblastic anemia.

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Gel Filtration Studies of Serum B12 Binding: An Abnormal Pattern in Patients with Vitamin B12 Deficiency

Blood ◽

10.1182/blood.v34.6.774.774 ◽

1969 ◽

Vol 34 (6) ◽

pp. 774-781 ◽

Cited By ~ 5

Author(s):

CHRISTINE LAWRENCE

Keyword(s):

Molecular Weight ◽

Vitamin B12 ◽

Binding Capacity ◽

Gel Filtration ◽

Vitamin B12 Deficiency ◽

Normal Serum ◽

B12 Deficiency ◽

Abnormal Pattern ◽

Normal Controls

Abstract 57CoB12 was added to serum in vitro to study its binding by the three known serum B12-binders in patients with vitamin B12 deficiency and in normal controls. Gel filtration through columns of Sephadex G-200 was used to separate the low (beta) and high (alpha1 and beta) molecular weight B12-binding fractions. Electrophoresis on filter paper was used to separate the alpha1- and beta-globulins. The alpha1-globulin fraction in the serum of B12-deficient patients bound more of the added 57CoB12 than did this fraction in normal serum, presumably because this binder of the serum endogenous vitamin B12 is much less saturated in B12-deficiency. However, the total B12 binding capacity of the alpha1-globulin (for endogenous plus added vitamin B12) was lower in B12-deficient than in normal serum. The low molecular weight beta-binder bound more added 57CoB12 in B12-deficient than in normal serum, whereas the high molecular weight beta binder had a much lower B12-binding capacity in deficient than in normal serum. These abnormalities were independent of the cause of the vitamin B12 deficiency and disappeared after successful treatment with vitamin B12.

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Holotranscobalamin Is a Useful Marker of Vitamin B12 Deficiency in Alcoholics

The Scientific World JOURNAL ◽

10.1100/2012/128182 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 6

Author(s):

Alberto Fragasso ◽

Clara Mannarella ◽

Angela Ciancio ◽

Oronzo Scarciolla ◽

Nicoletta Nuzzolese ◽

...

Keyword(s):

Vitamin B12 ◽

Vitamin B12 Deficiency ◽

Serum Levels ◽

Normal Serum ◽

Serum Folate ◽

Gamma Glutamyl Transpeptidase ◽

B12 Deficiency ◽

Male Patients ◽

Positive Correlations ◽

Glutamyl Transpeptidase

Background. Measurement of serum cobalamin (Cbl) levels is the standard investigation for assessing vitamin B12 deficiency. Falsely increased values of Cbl can be caused by alcoholic liver disease. Measurement of total vitamin B12 serum levels might be misleading in alcoholics, because a tissue metabolic deficiency is possible even with normal serum Cbl levels. Holotranscobalamin (HoloTC), the Cbl metabolically active fraction, is considered as a better index of vitamin B12 deficiency.Methods. For assessing vitamin B12 status, we evaluated 22 adult alcoholic male patients by measuring in parallel serum Cbl, serum folate and red blood cell folate levels, HoloTC levels by the AxSYM assay.Results. HoloTC values were reduced in 3 alcoholics with borderline-low Cbl values. Significant positive correlations were found between serum Cbl and HoloTC levels, serum Cbl and gamma-glutamyl transpeptidase (GGT).Conclusion. HoloTC measurement is a useful option for assessing vitamin B12 status in alcoholics, particularly in the subjects with borderline Cbl values and may be considered an early marker of vitamin B12 deficiency.

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The Kinetics of Intravenously Injected Radioactive Vitamin B12: Studies on Normal Subjects and Patients with Chronic Myelocytic Leukemia and Pernicious Anemia

Blood ◽

10.1182/blood.v15.5.646.646 ◽

1960 ◽

Vol 15 (5) ◽

pp. 646-661 ◽

Cited By ~ 16

Author(s):

EUGENE A. BRODY ◽

SOLOMON ESTREN ◽

LOUIS R. WASSERMAN

Keyword(s):

Vitamin B12 ◽

Pernicious Anemia ◽

Total Gastrectomy ◽

Binding Capacity ◽

Intrinsic Factor ◽

Normal Subjects ◽

High Serum ◽

Malabsorption Syndrome ◽

Chronic Myelocytic Leukemia ◽

Myelocytic Leukemia

Abstract 1. Studies of the fate of intravenously injected radioactive vitamin B12 have been performed in patients with normal, low and high serum concentrations of vitamin B12. 2. Abnormal plasma disappearance curves were noted in chronic myelocytic leukemia, pernicious anemia in relapse and in remission, total gastrectomy and malabsorption syndrome. 3. In chronic myelocytic leukemia, the slow clearance of plasma radioactivity may be explained by the increased binding capacity of the plasma proteins for vitamin B12. 4. Plasma clearance of radioactivity is slower than normal in pernicious anemia, even in remission. The failure of the disappearance curve to return to normal in pernicious anemia in complete remission suggests the existence of a plasma "B12-transferase," whose function is to transfer circulating B12 to the tissues. The disappearance curves suggest that the amount of such "B12-transferase" is diminished in pernicious anemia, total gastrectomy and certain Cases of malabsorption syndrome. 5. A relationship between a hypothetical "B12-transferase" and intrinsic factor is discussed.

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Folic acid metabolism in vitamin B12-deficient sheep. Effects of injected methionine on liver constituents associated with folate metabolism

Biochemical Journal ◽

10.1042/bj1420119 ◽

1974 ◽

Vol 142 (1) ◽

pp. 119-126 ◽

Cited By ~ 35

Author(s):

Jeffrey M. Gawthorne ◽

Richard M. Smith

Keyword(s):

Vitamin B12 ◽

Methylenetetrahydrofolate Reductase ◽

Vitamin B12 Deficiency ◽

Folate Metabolism ◽

British Library ◽

Synthetase Activity ◽

Intravenous Injections ◽

B12 Deficiency ◽

Lending Library

1. A study was made of the effects of injected l-methionine on the activity of several enzymes of folate metabolism, and on the transport of methotrexate in liver preparations from vitamin B12-deficient ewes and their pair-fed controls receiving vitamin B12. 2. The activities of dihydrofolate reductase (EC 1.5.1.3) and 5-methyltetrahydrofolate–homocysteine transmethylase were significantly decreased in the liver of vitamin B12-deficient animals, but were unaffected by l-methionine. 3. The concentration of S-adenosyl-l-methionine in the liver of deficient animals was about one-half of that in normal animals, and was restored to normal by either vitamin B12 or l-methionine. 4. Methylenetetrahydrofolate reductase (EC 1.1.1.68) from sheep liver was inhibited by S-adenosyl-l-methionine in vitro, but not by concentrations of S-adenosyl-l-methionine found in the liver of vitamin B12-deficient animals after injection of physiological amounts of l-methionine. 5. Pteroylpolyglutamate synthetase activity was significantly increased in the liver of vitamin B12-deficient animals, and was decreased by intravenous injections of l-methionine. 6. l-Methionine injections increased the initial rate of uptake of methotrexate in liver slices from deficient animals and acted synergistically with vitamin B12 to increase the quantity taken up in 40min. The failure of folate metabolism in vitamin B12 deficiency can be satisfactorily explained if l-methionine similarly affects the membrane transport of naturally occurring folates. 7. Further details of the results have been deposited as Supplementary Publication SUP 50028 (4 pages) at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.

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Serum Folate of Less than 7.0 ng/mL is a Marker of Malnutrition

American Journal of Clinical Pathology ◽

10.1093/ajcp/aqaa161.191 ◽

2020 ◽

Vol 154 (Supplement_1) ◽

pp. S87-S87

Author(s):

S N Mattox ◽

D Kozman ◽

G Singh

Keyword(s):

Vitamin B12 ◽

Clinical Laboratory ◽

Tertiary Care ◽

Vitamin B12 Deficiency ◽

Folate Deficiency ◽

Normal Serum ◽

Serum Folate ◽

Folate Supplementation ◽

B12 Deficiency ◽

The Difference

Abstract Introduction/Objective To identify clinical/laboratory factors associated with folate deficiency in tertiary care patients. Methods We reviewed the medical records of 1019 patients with serum folate <7.0 ng/mL, 301 patients with serum folate of 15 ng/mL, and 300 patients with serum folate > 23 ng/mL. Results Serum prealbumin levels were subnormal in 54.8% of patients with serum folate <7.0 ng/mL. Vitamin B12, hemoglobin, and serum albumin levels were significantly lower in the <7.0 ng/mL folate group. In 62.4% of patients with serum folate <7.0 ng/mL, 1 or more markers of malnutrition were present. The low-folate group had a significantly higher prevalence of gastrointestinal (GI) disorders, sepsis, and abnormal serum creatinine level. There were no significant differences in the 2 groups regarding diabetes; behavioral/neurological disorders, including drug and alcohol abuse; bariatric surgery; or a diagnosis of malnutrition. The average body mass index (BMI) for the <7.0 ng/mL and 15 ng/mL folate groups was significantly different (28.89 and 28.31, respectively), although the difference does not appear to be clinically meaningful. Conclusion The prevalence of folate deficiency depends on what is considered a normal serum folate level. Approximately 10% of tertiary care patients have levels <7.0 ng/mL and exhibit other markers of malnutrition. It is recommended that patients with GI disorders, chronic kidney disease, and sepsis be routinely tested for serum folate levels, before administration of vitamin supplements. Patients with serum folate levels <7.0 ng/mL should be evaluated for malnutrition, despite BMI > 25. Folate supplementation should be administered only after excluding coexisting vitamin B12 deficiency.

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Folic acid metabolism in vitamin B12-deficient sheep. Depletion of liver folates

Biochemical Journal ◽

10.1042/bj1360279 ◽

1973 ◽

Vol 136 (2) ◽

pp. 279-293 ◽

Cited By ~ 22

Author(s):

Richard M. Smith ◽

William S. Osborne-White

Keyword(s):

Urinary Excretion ◽

Vitamin B12 ◽

Acid Metabolism ◽

Vitamin B12 Deficiency ◽

Deficient Diet ◽

Severe Vitamin ◽

Quantitative Estimates ◽

Folic Acid Metabolism ◽

B12 Deficiency ◽

Microbiological Assays

1. Metabolism of folate was studied in six ewes in an advanced state of vitamin B12 deficiency as judged by voluntary food intake and in their pair-fed controls receiving vitamin B12. A group of four animals that were maintained throughout the experiment at pasture was also studied. 2. After 34–40 weeks on the cobalt-deficient diet urinary excretion of formiminoglutamate by four deficient animals was about 3.2mmol/day and this was not significantly decreased by injection of three of them with about 4.5μg of [2-14C]folate/kg body weight per day for 5 days. Three days after the last injection retention of [2-14C]folate by the livers of the deficient animals (5.5% of the dose) was lower than that of their pair-fed controls (26% of the dose) but there was no evidence of net retention of injected folate in the livers of either group. Urinary excretion of 14C indicated that renal clearance of folate may have been impaired in very severe vitamin B12 deficiency. 3. As estimated by microbiological assays total folates in the livers of animals at pasture (12.9μg/g) included about 24% of 5-methyltetrahydrofolate as compared with about 72% of a total of 12.5μg/g in three further ewes fed on a stock diet of wheaten hay-chaff and lucerne-chaff. Liver folates of vitamin B12-deficient animals (0.5μg/g) included about 88% of 5-methyltetrahydrofolate as compared with about 51% of a total of 5.2μg/g in pair-fed animals treated with vitamin B12. 4. Chromatography of liver folates of the pair-fed animals permitted quantitative estimates of the pteroylglutamates present. The results showed that the vitamin B12-deficient livers were more severely depleted of tetrahydrofolates and formyltetrahydrofolates than of methyltetrahydrofolates and that as the deficiency developed they were more severely depleted of the higher polyglutamates than of the monoglutamate within each of these classes. Results from animals injected with [2-14C]folate indicated an impairment of the exchange between pteroylmonoglutamates and pteroylpolyglutamates in the livers of deficient animals. 5. In vitamin B12-deficient animals with food intakes below 200g/day some of the liver folates were not completely reduced and some degradation of pteroylpolyglutamates was detected. The latter condition may have been associated with fatty liver. 6. The results are discussed in relation to current theories of vitamin B12–folate interactions.

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