scholarly journals Vitamin B12 deficiency and the excretion of ether-soluble acids in the rat

1967 ◽  
Vol 21 (2) ◽  
pp. 309-314 ◽  
Author(s):  
B. K. Armstrong
Keyword(s):  
Urinary Excretion ◽  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
Vitamin B ◽  
B12 Deficiency ◽  
Males And Females

1. Urinary excretion of total ether-soluble acids and of methylmalonic acid was studied in rats on vitamin B12-deficient diets with and without a vitamin B12 supplement.2. It was shown that urinary excretion of total ether-soluble acids and methylmalonic acid was increased in vitamin B12-deficient rats and that this increase was somewhat variable between individual animals, males and females, and rats from different litters.3. The increased excretion of these acids could readily be reversed by supplementing the diet with vitamin B12.

scholarly journals Improved testing for vitamin B12 deficiency: correcting MMA for eGFR reduces the number of patients classified as vitamin B12 deficient

2018 ◽  
Vol 55 (6) ◽  
pp. 685-692 ◽  
Author(s):  
Saskia LM van Loon ◽  
Anna M Wilbik ◽  
Uzay Kaymak ◽  
Edwin R van den Heuvel ◽  
Volkher Scharnhorst ◽  
...  
Keyword(s):  
Data Mining ◽  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
The Elderly ◽  
Vitamin B ◽  
Data Mining Approach ◽  
Number Of Patients ◽  
B12 Deficiency ◽  
The Relationship

Background Methylmalonic acid (MMA) can detect functional vitamin B12 deficiencies as it accumulates early when intracellular deficits arise. However, impaired clearance of MMA from blood due to decreased glomerular filtration rate (eGFR) also results in elevated plasma MMA concentrations. Alternative to clinical trials, a data mining approach was chosen to quantify and compensate for the effect of decreased eGFR on MMA concentration. Methods Comprehensive data on patient’s vitamin B12, eGFR and MMA concentrations were collected ( n = 2906). The relationship between vitamin B12, renal function (eGFR) and MMA was modelled using weighted multiple linear regression. The obtained model was used to estimate the influence of decreased eGFR on MMA. Clinical impact was examined by comparing the number of patients labelled vitamin B12 deficient with and without adjustment in MMA. Results Adjusting measured MMA concentrations for eGFR in the group of patients with low-normal vitamin B12 concentrations (90–300 pmol/L) showed that the use of unadjusted MMA concentrations overestimates vitamin B12 deficiency by 40%. Conclusions Through a data mining approach, the influence of eGFR on the relation between MMA and vitamin B12 can be quantified and used to correct the measured MMA concentration for decreased eGFR. Especially in the elderly, eGFR-based correction of MMA may prevent over-diagnosis of vitamin B12 deficiency and corresponding treatment.

The relationship between the cobalt nutrition of ewes and the vitamin B12 status of ewes and their lambs

1987 ◽  
Vol 38 (6) ◽  
pp. 1071 ◽  
Author(s):  
MF Quirk ◽  
BW Norton
Keyword(s):  
Vitamin B12 ◽  
Milk Production ◽  
Acid Concentration ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
Lactation Performance ◽  
Lower Productivity ◽  
Cotton South ◽  
B12 Deficiency ◽  
The Relationship

An experiment was undertaken at Mt Cotton, south-east Queensland, to investigate the relationship between the cobalt nutrition of ewes and the occurrence of vitamin B12 deficiency in ewes and their lambs. Ewes received either no supplementary cobalt (C), 0.03 mg cobalt day-1 (LC), 0.06 mg cobalt day-1 (HC) or a cobalt bullet and grinder (CB). LC and HC ewes received their supplement as a weekly drench. Supplementation commenced prior to joining, and ewes subsequently grazed pangola grass pastures containing between 0.05 and 0.11 mg kg-1 cobalt.Cobalt supplementation of ewes increased their liveweight, reproductive and lactation performance. The milk production of ewes was influenced by the level of supplementation, with C, LC, HC and CB ewes producing 31.1, 41.5, 47.7 and 50.31. of milk respectively during the first 4 weeks of lactation. The lower productivity of C ewes was associated with concentrations of vitamin B12 in serum of less than 200 pg ml-1 and with the presence of detectable concentrations of methylmalonic acid (>80 8moles l-1) and formiminoglutamic acid (>30 8moles l-1) in their urine.The growth of lambs was influenced by the cobalt nutrition of their dams; the mean liveweight gain from birth to weaning (14 weeks of age) for lambs from C, LC, HC and CB ewes was 95, 158, 194 and 231 g day-1. Vitamin B12 deficiency was evident in lambs reared by C ewes from 4 weeks of age, but lambs from LC and HC ewes did not become deficient until 8 and 12 weeks of age respectively. Lambs from CB ewes remained free of signs of deficiency prior to weaning. Urinary formiminoglutamic acid concentration was a more reliable indicator of vitamin B12 status in young lambs than urinary methylmalonic acid concentration. The concentrations of vitamin B12 in the serum of lambs were low in all groups (< 150 pg ml-1) and were generally unaffected by the cobalt nutrition of their dams.A dietary cobalt intake of about 0.15 mg day-1 appeared to be necessary for optimal milk production from ewes. However, this level of dietary cobalt was inadequate for provision of sufficient quantities of maternal vitamin B12 to meet the requirements of lambs in the later stages of lactation.

scholarly journals Homocystinuria masquerading as vitamin B12 deficiency

2012 ◽  
Vol 4 (2) ◽  
pp. 326-328
Author(s):  
M Wadhwani ◽  
S Beri ◽  
A Saili ◽  
S Garg
Keyword(s):  
Vitamin B12 ◽  
Megaloblastic Anemia ◽  
Vitamin B12 Deficiency ◽  
Interesting Case ◽  
Vitamin B ◽  
Ophthalmological Examination ◽  
Ophthalmic Manifestations ◽  
History Of ◽  
B12 Deficiency ◽  
Vitamin B 12

Background: Homocystinuria is a rare metabolic disorder charcterised by excess homocysteine in the urine. Vitamin B12 deficiency has diverse cutaneous, nervous and ophthalmic manifestations. Objective: To report a case of homocystinuria masquerading as vitamin B 12 deficiency. Case: We hereby are presenting an interesting case of a 4 year old boy who was being treated for Vitamin B 12 deficiency on the basis of history of delayed milestone, abdominal pain and hyperpigmentation of skin which was diagnosed as homocystinuria. Conclusion: It is important to carry out ophthalmological examination in every case of megaloblastic anemia if associated with blurring of vision and mental retardation.DOI: http://dx.doi.org/10.3126/nepjoph.v4i2.6554 Nepal J Ophthalmol 2012; 4 (8): 326-328

scholarly journals Factors affecting formiminoglutamic acid excretion in vitamin B12 deficiency

1970 ◽  
Vol 116 (4) ◽  
pp. 681-688 ◽  
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.

Metabolic precursors of methylmalonic acid in vitamin B12 deficiency

1967 ◽  
Vol 18 (2) ◽  
pp. 197-204 ◽  
Author(s):  
D. Gompertz ◽  
J.Hywel Jones ◽  
J.P. Knowles
Keyword(s):  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
B12 Deficiency ◽  
Metabolic Precursors
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