scholarly journals The effect of nitrous oxide inactivation of vitamin B12 on rat hepatic folate. Implications for the methylfolate-trap hypothesis

1980 ◽  
Vol 186 (3) ◽  
pp. 933-936 ◽  
Author(s):  
M Lumb ◽  
R Deacon ◽  
J Perry ◽  
I Chanarin ◽  
B Minty ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
Folate Metabolism ◽  
Transient Increase ◽  
Initial Value ◽  
B12 Deficiency ◽  
Liver Folate

Rats exposed to N20 show a decrease in liver folate to about 25% of the initial value after 10 days. There is a transient increase in the amount of 5-methylterrahydropteroylpolyglutamate in the first 24 h, but thereafter the content decreases. The level of 5-methyltetrahydropterolymonoglutamate declines without any transitory increase. The transient accumulation of 5-methyltetrahydropteroylpolyglutamate is due to failure of methionine synthetase. Thereafter the decrease in the amount of methylfolate makes it improbable that trapping of methylfolate is the explanation for failure of folate metabolism in vitamin B12 deficiency.

scholarly journals Subacute Combined Degeneration of the Spinal Cord due to Different Etiologies and Improvement of MRI Findings

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Azize Esra Gürsoy ◽  
Mehmet Kolukısa ◽  
Gülsen Babacan-Yıldız ◽  
Arif Çelebi
Keyword(s):  
Spinal Cord ◽  
Nitrous Oxide ◽  
Vitamin B12 ◽  
Neurological Complication ◽  
Vitamin B12 Deficiency ◽  
Vegetarian Diet ◽  
Mri Findings ◽  
Subacute Combined Degeneration ◽  
B12 Deficiency ◽  
Reversible Condition

Subacute combined degeneration (SCD) is a rare neurological complication of vitamin B12 deficiency, characterized by demyelination of the dorsal and lateral spinal cord. Herein, we describe three cases, who presented with SCD, one related to reduced intake of vitamin B12 because of a vegetarian diet and two related to nitrous oxide exposure during surgery. MR images of our patients revealed symmetrical hyperintense signals in dorsal and lateral columns in T2 weighted series. After treatment with intramuscular B12 injections (1 mg daily for 2 weeks, once weekly thereafter for three months) all patients showed improvement of their symptoms. Abnormalities of the spinal cord on MRI resolved in three months. In conclusion, SCD either due to nitrous oxide exposure or due to reduced intake of vitamin B12 is a reversible condition, when detected and treated early.

scholarly journals Elucidating Unique Axonal Dysfunction Between Nitrous Oxide Abuse and Vitamin B12 Deficiency

2019 ◽  
Vol 10 ◽  
Author(s):  
Jowy Tani ◽  
Hsing-Yu Weng ◽  
Hung-Ju Chen ◽  
Tsui-San Chang ◽  
Jia-Ying Sung ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
B12 Deficiency ◽  
Axonal Dysfunction

NITROUS OXIDE ANAESTHESIA INDUCED VITAMIN B12 DEFICIENCY PRESENTING AS ACUTE MYELONEUROPATHY

2018 ◽  
Vol 5 (5) ◽  
pp. 330
Author(s):  
Manish Tyagi ◽  
Harshavardhan Sampath ◽  
Geeta Soohinda ◽  
Sanjiba Dutta
Keyword(s):  
Nitrous Oxide ◽  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
Nitrous Oxide Anaesthesia ◽  
Oxide Anaesthesia ◽  
B12 Deficiency

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

1974 ◽  
Vol 142 (1) ◽  
pp. 119-126 ◽  
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.

Myeloneuropathy from Whipped Cream Bulbs Presenting as Conversion Disorder

1997 ◽  
Vol 31 (1) ◽  
pp. 131-132 ◽  
Author(s):  
Adam Brett
Keyword(s):  
Nitrous Oxide ◽  
Vitamin B12 ◽  
Psychiatric Hospital ◽  
Neurological Examination ◽  
Vitamin B12 Deficiency ◽  
Conversion Disorder ◽  
Neurological Symptoms ◽  
Recreational Drug ◽  
B12 Deficiency ◽  
Whipped Cream

Objective:To highlight the complications of nitrous oxide abuse. Clinical picture:A case is presented of a myeloneuropathy in a 21-year-old woman who had been abusing nitrous oxide, obtained from whipped cream bulbs, who was referred to a psychiatric hospital with a diagnosis of conversion disorder. Nitrous oxide toxicity has been reported in medical and dental professions and a few cases of myeloneuropathy due to induced vitamin B12 deficiency have been reported. This would appear to be the first reported case of myeloneuropathy resulting from nitrous oxide abuse from whipped cream propellants as a recreational drug in the community. Treatment:Three doses of intramuscular hydroxy cobalamin (1000 μg) over the course of 1 week. Outcome:Her neurological symptoms and anxiety settled. Conclusions:Nitrous oxide is becoming more popular as a recreational drug; its complications should be noted and a thorough neurological examination performed if abuse is suspected.

Sign in / Sign up

Export Citation Format

Share Document